This change permits users of the ChaCha20/Poly1305 algorithms
(and the AEAD construction thereof) to pass NULL pointers for
data that they do not need, and avoids the need to provide a valid
buffer for data that is not used.
This implementation is based off the description in RFC 7539.
The ChaCha20 code is also updated to provide a means of generating
keystream blocks with arbitrary counter values. This is used to
generated the one-time Poly1305 key in the AEAD construction.
* development: (504 commits)
Fix minor code style issues
Add the uodate to the soversion to the ChangeLog
Fix the ChangeLog for clarity, english and credit
Update version to 2.9.0
ecp: Fix binary compatibility with group ID
Changelog entry
Change accepted ciphersuite versions when parsing server hello
Remove preprocessor directives around platform_util.h include
Fix style for mbedtls_mpi_zeroize()
Improve mbedtls_platform_zeroize() docs
mbedtls_zeroize -> mbedtls_platform_zeroize in docs
Reword config.h docs for MBEDTLS_PLATFORM_ZEROIZE_ALT
Organize CMakeLists targets in alphabetical order
Organize output objs in alfabetical order in Makefile
Regenerate errors after ecp.h updates
Update ecp.h
Change variable bytes_written to header_bytes in record decompression
Update ecp.h
Update ecp.h
Update ecp.h
...
Rename to mbedtls_ssl_get_async_operation_data and
mbedtls_ssl_set_async_operation_data so that they're about
"async operation data" and not about some not-obvious "data".
When a handshake step starts an asynchronous operation, the
application needs to know which SSL connection the operation is for,
so that when the operation completes, the application can wake that
connection up. Therefore the async start callbacks need to take the
SSL context as an argument. It isn't enough to let them set a cookie
in the SSL connection, the application needs to be able to find the
right SSL connection later.
Also pass the SSL context to the other callbacks for consistency. Add
a new field to the handshake that the application can use to store a
per-connection context. This new field replaces the former
context (operation_ctx) that was created by the start function and
passed to the resume function.
Add a boolean flag to the handshake structure to track whether an
asynchronous operation is in progress. This is more robust than
relying on the application to set a non-null application context.
Change the signature of mbedtls_ssl_handshake_free again. Now take the
whole SSL context as argument and not just the configuration and the
handshake substructure.
This is in preparation for changing the asynchronous cancel callback
to take the SSL context as an argument.
In the refactoring of ssl_parse_encrypted_pms, I advertently broke the
case when decryption signalled an error, with the variable ret getting
overwritten before calculating diff. Move the calculation of diff
immediately after getting the return code to make the connection more
obvious. Also move the calculation of mask immediately after the
calculation of diff, which doesn't change the behavior, because I find
the code clearer that way.
Conflict resolution:
* ChangeLog: put the new entry from my branch in the proper place.
* include/mbedtls/error.h: counted high-level module error codes again.
* include/mbedtls/ssl.h: picked different numeric codes for the
concurrently added errors; made the new error a full sentence per
current standards.
* library/error.c: ran scripts/generate_errors.pl.
* library/ssl_srv.c:
* ssl_prepare_server_key_exchange "DHE key exchanges": the conflict
was due to style corrections in development
(4cb1f4d49c) which I merged with
my refactoring.
* ssl_prepare_server_key_exchange "For key exchanges involving the
server signing", first case, variable declarations: merged line
by line:
* dig_signed_len: added in async
* signature_len: removed in async
* hashlen: type changed to size_t in development
* hash: size changed to MBEDTLS_MD_MAX_SIZE in async
* ret: added in async
* ssl_prepare_server_key_exchange "For key exchanges involving the
server signing", first cae comment: the conflict was due to style
corrections in development (4cb1f4d49c)
which I merged with my comment changes made as part of refactoring
the function.
* ssl_prepare_server_key_exchange "Compute the hash to be signed" if
`md_alg != MBEDTLS_MD_NONE`: conflict between
ebd652fe2d
"ssl_write_server_key_exchange: calculate hashlen explicitly" and
46f5a3e9b4 "Check return codes from
MD in ssl code". I took the code from commit
ca1d742904 made on top of development
which makes mbedtls_ssl_get_key_exchange_md_ssl_tls return the
hash length.
* programs/ssl/ssl_server2.c: multiple conflicts between the introduction
of MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS and new auxiliary functions and
definitions for async support, and the introduction of idle().
* definitions before main: concurrent additions, kept both.
* main, just after `handshake:`: in the loop around
mbedtls_ssl_handshake(), merge the addition of support for
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS and SSL_ASYNC_INJECT_ERROR_CANCEL
with the addition of the idle() call.
* main, if `opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM`: take the
code from development and add a check for
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS.
* main, loop around mbedtls_ssl_read() in the datagram case:
take the code from development and add a check for
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS; revert to a do...while loop.
* main, loop around mbedtls_ssl_write() in the datagram case:
take the code from development and add a check for
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS; revert to a do...while loop.
In mbedtls_ssl_get_key_exchange_md_tls1_2, add an output parameter for
the hash length. The code that calls this function can currently do
without it, but it will need the hash length in the future, when
adding support for a third-party callback to calculate the signature
of the hash.
Reorganize ssl_parse_encrypted_pms so that it first prepares the
ciphertext to decrypt, then decrypts it, then returns either the
decrypted premaster secret or random data in an appropriate manner.
This is in preparation for allowing the private key operation to be
offloaded to an external cryptographic module which can operate
asynchronously. The refactored code no longer calculates state before
the decryption that needs to be saved until after the decryption,
which allows the decryption to be started and later resumed.
Use the public key to extract metadata rather than the public key.
Don't abort early if there is no private key.
This is in preparation for allowing the private key operation to be
offloaded to an external cryptographic module.
Implement SSL asynchronous private operation for the case of a
signature operation in a server.
This is a first implementation. It is functional, but the code is not
clean, with heavy reliance on goto.
The pk layer can infer the hash length from the hash type. Calculate
it explicitly here anyway because it's needed for debugging purposes,
and it's needed for the upcoming feature allowing the signature
operation to be offloaded to an external cryptographic processor, as
the offloading code will need to know what length hash to copy.
New compile-time option MBEDTLS_SSL_ASYNC_PRIVATE_C, enabling
callbacks to replace private key operations. These callbacks allow the
SSL stack to make an asynchronous call to an external cryptographic
module instead of calling the cryptography layer inside the library.
The call is asynchronous in that it may return the new status code
MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS, in which case the SSL stack returns
and can be later called where it left off.
This commit introduces the configuration option. Later commits will
implement the feature proper.
This function is declared in ssl_internal.h, so this is not a public
API change.
This is in preparation for mbedtls_ssl_handshake_free needing to call
methods from the config structure.
In SSL, don't use mbedtls_pk_ec or mbedtls_pk_rsa on a private
signature or decryption key (as opposed to a public key or a key used
for DH/ECDH). Extract the data (it's the same data) from the public
key object instead. This way the code works even if the private key is
opaque or if there is no private key object at all.
Specifically, with an EC key, when checking whether the curve in a
server key matches the handshake parameters, rely only on the offered
certificate and not on the metadata of the private key.
* public/pr/1380:
Update ChangeLog for #1380
Generate RSA keys according to FIPS 186-4
Generate primes according to FIPS 186-4
Avoid small private exponents during RSA key generation
Change mbedtls_zeroize() implementation to use memset() instead of a
custom implementation for performance reasons. Furthermore, we would
also like to prevent as much as we can compiler optimisations that
remove zeroization code.
The implementation of mbedtls_zeroize() now uses a volatile function
pointer to memset() as suggested by Colin Percival at:
http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buffer.html
Add a new macro MBEDTLS_UTILS_ZEROIZE that allows users to configure
mbedtls_zeroize() to an alternative definition when defined. If the
macro is not defined, then mbed TLS will use the default definition of
the function.
This commit removes all the static occurrencies of the function
mbedtls_zeroize() in each of the individual .c modules. Instead the
function has been moved to utils.h that is included in each of the
modules.
The new header contains common information across various mbed TLS
modules and avoids code duplication. To start, utils.h currently only
contains the mbedtls_zeroize() function.
The specification requires that P and Q are not too close. The specification
also requires that you generate a P and stick with it, generating new Qs until
you have found a pair that works. In practice, it turns out that sometimes a
particular P results in it being very unlikely a Q can be found matching all
the constraints. So we keep the original behavior where a new P and Q are
generated every round.
The specification requires that numbers are the raw entropy (except for odd/
even) and at least 2^(nbits-0.5). If not, new random bits need to be used for
the next number. Similarly, if the number is not prime new random bits need to
be used.
Attacks against RSA exist for small D. [Wiener] established this for
D < N^0.25. [Boneh] suggests the bound should be N^0.5.
Multiple possible values of D might exist for the same set of E, P, Q. The
attack works when there exists any possible D that is small. To make sure that
the generated key is not susceptible to attack, we need to make sure we have
found the smallest possible D, and then check that D is big enough. The
Carmichael function λ of p*q is lcm(p-1, q-1), so we can apply Carmichael's
theorem to show that D = d mod λ(n) is the smallest.
[Wiener] Michael J. Wiener, "Cryptanalysis of Short RSA Secret Exponents"
[Boneh] Dan Boneh and Glenn Durfee, "Cryptanalysis of RSA with Private Key d Less than N^0.292"
Clang-Msan is known to report spurious errors when MBEDTLS_AESNI_C is
enabled, due to the use of assembly code. The error reports don't
mention AES, so they can be difficult to trace back to the use of
AES-NI. Warn about this potential problem at compile time.
Zeroing out an fd_set before calling FD_ZERO on it is in principle
useless, but without it some memory sanitizers think the fd_set is
still uninitialized after FD_ZERO (e.g. clang-msan/Glibc/x86_64 where
FD_ZERO is implemented in assembly). Make the zeroing conditional on
using a memory sanitizer.
The initialization via FD_SET is not seen by memory sanitizers if
FD_SET is implemented through assembly. Additionally zeroizing the
respective fd_set's before calling FD_SET contents the sanitizers
and comes at a negligible computational overhead.
In mbedtls_ssl_derive_keys, don't call mbedtls_md_hmac_starts in
ciphersuites that don't use HMAC. This doesn't change the behavior of
the code, but avoids relying on an uncaught error when attempting to
start an HMAC operation that hadn't been initialized.
Clarify what MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH and
MBEDTLS_ERR_PK_SIG_LEN_MISMATCH mean. Add comments to highlight that
this indicates that a valid signature is present, unlike other error
codes. See
https://github.com/ARMmbed/mbedtls/pull/1149#discussion_r178130705
Conflict resolution:
* ChangeLog
* tests/data_files/Makefile: concurrent additions, order irrelevant
* tests/data_files/test-ca.opensslconf: concurrent additions, order irrelevant
* tests/scripts/all.sh: one comment change conflicted with a code
addition. In addition some of the additions in the
iotssl-1381-x509-verify-refactor-restricted branch need support for
keep-going mode, this will be added in a subsequent commit.
The relevant ASN.1 definitions for a PKCS#8 encoded Elliptic Curve key are:
PrivateKeyInfo ::= SEQUENCE {
version Version,
privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
privateKey PrivateKey,
attributes [0] IMPLICIT Attributes OPTIONAL
}
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL
}
ECParameters ::= CHOICE {
namedCurve OBJECT IDENTIFIER
-- implicitCurve NULL
-- specifiedCurve SpecifiedECDomain
}
ECPrivateKey ::= SEQUENCE {
version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
privateKey OCTET STRING,
parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
publicKey [1] BIT STRING OPTIONAL
}
Because of the two optional fields, there are 4 possible variants that need to
be parsed: no optional fields, only parameters, only public key, and both
optional fields. Previously mbedTLS was unable to parse keys with "only
parameters". Also, only "only public key" was tested. There was a test for "no
optional fields", but it was labelled incorrectly as SEC.1 and not run because
of a great renaming mixup.
check-names.sh reserves the prefix MBEDTLS_ for macros defined in
config.h so this name (or check-names.sh) had to change.
This is also more flexible because it allows for platforms that don't have
an EINTR equivalent or have multiple such values.
Also, introduce MBEDTLS_EINTR locally in net_sockets.c
for the platform-dependent return code macro used by
the `select` call to indicate that the poll was interrupted
by a signal handler: On Unix, the corresponding macro is EINTR,
while on Windows, it's WSAEINTR.
If the select UNIX system call is interrupted by a signal handler,
it is not automatically restarted but returns EINTR. This commit
modifies the use of select in mbedtls_net_poll from net_sockets.c
to retry the select call in this case.
Found by running:
CC=clang cmake -D CMAKE_BUILD_TYPE="Check"
tests/scripts/depend-pkalgs.pl
(Also tested with same command but CC=gcc)
Another PR will address improving all.sh and/or the depend-xxx.pl scripts
themselves to catch this kind of thing.
library\x509_crt.c(2137): warning C4267: 'function' : conversion from 'size_t' to 'int', possible loss of data
library\x509_crt.c(2265): warning C4267: 'function' : conversion from 'size_t' to 'int', possible loss of data
* development: (557 commits)
Add attribution for #1351 report
Adapt version_features.c
Note incompatibility of truncated HMAC extension in ChangeLog
Add LinkLibraryDependencies to VS2010 app template
Add ChangeLog entry for PR #1382
MD: Make deprecated functions not inline
Add ChangeLog entry for PR #1384
Have Visual Studio handle linking to mbedTLS.lib internally
Mention in ChangeLog that this fixes#1351
Add issue number to ChangeLog
Note in the changelog that this fixes an interoperability issue.
Style fix in ChangeLog
Add ChangeLog entries for PR #1168 and #1362
Add ChangeLog entry for PR #1165
ctr_drbg: Typo fix in the file description comment.
dhm: Fix typo in RFC 5114 constants
tests_suite_pkparse: new PKCS8-v2 keys with PRF != SHA1
data_files/pkcs8-v2: add keys generated with PRF != SHA1
tests/pkcs5/pbkdf2_hmac: extend array to accommodate longer results
tests/pkcs5/pbkdf2_hmac: add unit tests for additional SHA algorithms
...
Fix warnings from gcc -O -Wall about `ret` used uninitialized in
CMAC selftest auxiliary functions. The variable was indeed
uninitialized if the function was called with num_tests=0 (which
never happens).
Use specific instructions for moving bytes around in a word. This speeds
things up, and as a side-effect, slightly lowers code size.
ARIA_P3 and ARIA_P1 are now 1 single-cycle instruction each (those
instructions are available in all architecture versions starting from v6-M).
Note: ARIA_P3 was already translated to a single instruction by Clang 3.8 and
armclang 6.5, but not arm-gcc 5.4 nor armcc 5.06.
ARIA_P2 is already efficiently translated to the minimal number of
instruction (1 in ARM mode, 2 in thumb mode) by all tested compilers
Manually compiled and inspected generated code with the following compilers:
arm-gcc 5.4, clang 3.8, armcc 5.06 (with and without --gnu), armclang 6.5.
Size reduction (arm-none-eabi-gcc -march=armv6-m -mthumb -Os): 5288 -> 5044 B
Effect on executing time of self-tests on a few boards:
FRDM-K64F (Cortex-M4): 444 -> 385 us (-13%)
LPC1768 (Cortex-M3): 488 -> 432 us (-11%)
FRDM-KL64Z (Cortex-M0): 1429 -> 1134 us (-20%)
Measured using a config.h with no cipher mode and the following program with
aria.c and aria.h copy-pasted to the online compiler:
#include "mbed.h"
#include "aria.h"
int main() {
Timer t;
t.start();
int ret = mbedtls_aria_self_test(0);
t.stop();
printf("ret = %d; time = %d us\n", ret, t.read_us());
}
(A similar commit for Arm follows.)
Use specific instructions for moving bytes around in a word. This speeds
things up, and as a side-effect, slightly lowers code size.
ARIA_P3 (aka reverse byte order) is now 1 instruction on x86, which speeds up
key schedule. (Clang 3.8 finds this but GCC 5.4 doesn't.)
I couldn't find an Intel equivalent of ARM's ret16 (aka ARIA_P1), so I made it
two instructions, which is still much better than the code generated with
the previous mask-shift-or definition, and speeds up en/decryption. (Neither
Clang 3.8 nor GCC 5.4 find this.)
Before:
O aria.o ins
s 7976 43,865
2 10520 37,631
3 13040 28,146
After:
O aria.o ins
s 7768 33,497
2 9816 28,268
3 11432 20,829
For measurement method, see previous commit:
"aria: turn macro into static inline function"
This decreases the size with -Os by nearly 1k while
not hurting performance too much with -O2 and -O3
Before:
O aria.o ins
s 8784 41,408
2 11112 37,001
3 13096 27,438
After:
O aria.o ins
s 7976 43,865
2 10520 37,631
3 13040 28,146
(See previous commit for measurement details.)
Besides documenting types better and so on, this give the compiler more room
to optimise either for size or performance.
Here are some before/after measurements of:
- size of aria.o in bytes (less is better)
- instruction count for the selftest function (less is better)
with various -O flags.
Before:
O aria.o ins
s 10896 37,256
2 11176 37,199
3 12248 27,752
After:
O aria.o ins
s 8784 41,408
2 11112 37,001
3 13096 27,438
The new version allows the compiler to reach smaller size with -Os while
maintaining (actually slightly improving) performance with -O2 and -O3.
Measurements were done on x86_64 (but since this is mainly about inlining
code, this should transpose well to other platforms) using the following
helper program and script, after disabling CBC, CFB and CTR in config.h, in
order to focus on the core functions.
==> st.c <==
#include "mbedtls/aria.h"
int main( void ) {
return mbedtls_aria_self_test( 0 );
}
==> p.sh <==
#!/bin/sh
set -eu
ccount () {
(
valgrind --tool=callgrind --dump-line=no --callgrind-out-file=/dev/null --collect-atstart=no --toggle-collect=main $1
) 2>&1 | sed -n -e 's/.*refs: *\([0-9,]*\)/\1/p'
}
printf "O\taria.o\tins\n"
for O in s 2 3; do
GCC="gcc -Wall -Wextra -Werror -Iinclude"
$GCC -O$O -c library/aria.c
$GCC -O1 st.c aria.o -o st
./st
SIZE=$( du -b aria.o | cut -f1 )
INS=$( ccount ./st )
printf "$O\t$SIZE\t$INS\n"
done
We're not absolutely consistent in the rest of the library, but we tend to use
C99-style comments less often.
Change to use C89-style comments everywhere except for end-of-line comments
Those suites were defined in ciphersuite_definitions[] but not included in
ciphersuite_preference[] which meant they couldn't be negotiated unless
explicitly added by the user. Add them so that they're usable by default like
any other suite.
In 2.7.0, we replaced a number of MD functions with deprecated inline
versions. This causes ABI compatibility issues, as the functions are no
longer guaranteed to be callable when built into a shared library.
Instead, deprecate the functions without also inlining them, to help
maintain ABI backwards compatibility.
Add missing MBEDTLS_DEPRECATED_REMOVED guards around the definitions
of mbedtls_aes_decrypt and mbedtls_aes_encrypt.
This fixes the build under -Wmissing-prototypes -Werror.
Fixes#1388
Currently only SHA1 is supported as PRF algorithm for PBKDF2
(PKCS#5 v2.0).
This means that keys encrypted and authenticated using
another algorithm of the SHA family cannot be decrypted.
This deficiency has become particularly incumbent now that
PKIs created with OpenSSL1.1 are encrypting keys using
hmacSHA256 by default (OpenSSL1.0 used PKCS#5 v1.0 by default
and even if v2 was forced, it would still use hmacSHA1).
Enable support for all the digest algorithms of the SHA
family for PKCS#5 v2.0.
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
1. Style issues fixes - remove redundant spacing.
2. Remove depency of `MBEDTLS_RSA_C` in `pk_parse_public_keyfile_rsa()`
tests, as the function itself is dependent on it.
- Rephrase file/function/parameter/enum/define/error descriptions into full
and clear sentences.
- Make sure to adhere to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
- Add full standard name in file description.
GitHub PR: #1316
- Rephrase file/function/parameter/enum/define/error descriptions into full
and clear sentences.
- Make sure to adhere to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
- Rephrase the descriptions of all md_alg and hashlen parameters.
GitHub PR: #1327
- Rephrase file/function/parameter/enum/define/error descriptions into full
and clear sentences.
- Make sure to adhere to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
- Standardize defines documentation
GitHub PR: #1323
- Rephrase function/parameter/enum/define/error descriptions into full and
clear sentences.
- Make sure to adhere to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
GitHub PR: #1306
- Rephrase function/parameter/enum/define/error descriptions into full and
clear sentences.
- Make sure to adhering to the Arm writing guidelines.
- Fix missing/incorrect Doxygen tags.
- Standardize terminology used within the file.
- Fix iv_len values per the standard.
GitHub PR: #1305
- Separate "\file" blocks from copyright, so that Doxygen doesn't repeat
the copyright information in all the Detailed Descriptions.
- Improve phrasing and clarity of functions, parameters, defines and enums.
GitHub PR: #1292
A new test for mbedtls_timing_alarm(0) was introduced in PR 1136, which also
fixed it on Unix. Apparently test results on MinGW were not checked at that
point, so we missed that this new test was also failing on this platform.
Add MBEDTLS_ERR_XXX_HW_ACCEL_FAILED error codes for all cryptography
modules where the software implementation can be replaced by a hardware
implementation.
This does not include the individual message digest modules since they
currently have no way to return error codes.
This does include the higher-level md, cipher and pk modules since
alternative implementations and even algorithms can be plugged in at
runtime.
This commit allows users to provide alternative implementations of the
ECJPAKE interface through the configuration option MBEDTLS_ECJPAKE_ALT.
When set, the user must add `ecjpake_alt.h` declaring the same
interface as `ecjpake.h`, as well as add some compilation unit which
implements the functionality. This is in line with the preexisting
support for alternative implementations of other modules.
The corner cases fixed include:
* Allocating a buffer of size 0. With this change, the allocator now
returns a NULL pointer in this case. Note that changes in pem.c and
x509_crl.c were required to fix tests that did not work under this
assumption.
* Initialising the allocator with less memory than required for headers.
* Fix header chain checks for uninitialised allocator.
The _ext suffix suggests "new arguments", but the new functions have
the same arguments. Use _ret instead, to convey that the difference is
that the new functions return a value.
Conflict resolution:
* ChangeLog: put the new entries in their rightful place.
* library/x509write_crt.c: the change in development was whitespace
only, so use the one from the iotssl-1251 feature branch.
This commit adds some explicit downcasts from `size_t` to `uint8_t` in
the RSASSA signature encoding function `rsa_rsassa_pkcs1_v15_encode`.
The truncation is safe as it has been checked beforehand that the
respective values are in the range of a `uint8_t`.
1) `mbedtls_rsa_import_raw` used an uninitialized return
value when it was called without any input parameters.
While not sensible, this is allowed and should be a
succeeding no-op.
2) The MPI test for prime generation missed a return value
check for a call to `mbedtls_mpi_shift_r`. This is neither
critical nor new but should be fixed.
3) Both the RSA keygeneration example program and the
RSA test suites contained code initializing an RSA context
after a potentially failing call to CTR DRBG initialization,
leaving the corresponding RSA context free call in the
cleanup section of the respective function orphaned.
While this defect existed before, Coverity picked up on
it again because of newly introduced MPI's that were
also wrongly initialized only after the call to CTR DRBG
init. The commit fixes both the old and the new issue
by moving the initializtion of both the RSA context and
all MPI's prior to the first potentially failing call.
A previous commit changed the record encryption function
`ssl_encrypt_buf` to compute the MAC in a temporary buffer
and copying the relevant part of it (which is strictly smaller
if the truncated HMAC extension is used) to the outgoing message
buffer. However, the change was only made in case Encrypt-Then-MAC
was enabled, but not in case of MAC-Then-Encrypt. While this
doesn't constitute a problem, for the sake of uniformity this
commit changes `ssl_encrypt_buf` to compute the MAC in a temporary
buffer in this case, too.
The function `mbedtls_rsa_complete` is supposed to guarantee that
RSA operations will complete without failure. In contrast, it does
not ensure consistency of parameters, which is the task of the
checking functions `rsa_check_pubkey` and `rsa_check_privkey`.
Previously, the maximum allowed size of the RSA modulus was checked
in `mbedtls_rsa_check_pubkey`. However, exceeding this size would lead
to failure of some RSA operations, hence this check belongs to
`mbedtls_rsa_complete` rather than `mbedtls_rsa_check_pubkey`.
This commit moves it accordingly.
The function `pk_get_rsapubkey` originally performed some basic
sanity checks (e.g. on the size of public exponent) on the parsed
RSA public key by a call to `mbedtls_rsa_check_pubkey`.
This check was dropped because it is not possible to thoroughly
check full parameter sanity (i.e. that (-)^E is a bijection on Z/NZ).
Still, for the sake of not silently changing existing behavior,
this commit puts back the call to `mbedtls_rsa_check_pubkey`.
- Adapt the change in all.sh to the new keep-going mode
- Restore alphabetical order of configuration flags for
alternative implementations in config.h and rebuild
library/version_features.c
`mbedtls_rsa_deduce_primes` implicitly casts the result of a call to
`mbedtls_mpi_lsb` to a `uint16_t`. This is safe because of the size
of MPI's used in the library, but still may have compilers complain
about it. This commit makes the cast explicit.
Conflict resolution: additions in the same places as
upstream-public/pr/865, both adding into lexicographically sorted
lists, resolved by taking the additions in lexicographic order.
* development:
Timing self test: shorten redundant tests
Timing self test: increased duration
Timing self test: increased tolerance
Timing unit tests: more protection against infinite loops
Unit test for mbedtls_timing_hardclock
New timing unit tests
selftest: allow excluding a subset of the tests
selftest: allow running a subset of the tests
selftest: refactor to separate the list of tests from the logic
Timing self test: print some diagnosis information
mbedtls_timing_get_timer: don't use uninitialized memory
timing interface documentation: minor clarifications
Timing: fix mbedtls_set_alarm(0) on Unix/POSIX
* public/pr/1136:
Timing self test: shorten redundant tests
Timing self test: increased duration
Timing self test: increased tolerance
Timing unit tests: more protection against infinite loops
Unit test for mbedtls_timing_hardclock
New timing unit tests
selftest: allow excluding a subset of the tests
selftest: allow running a subset of the tests
selftest: refactor to separate the list of tests from the logic
Timing self test: print some diagnosis information
mbedtls_timing_get_timer: don't use uninitialized memory
timing interface documentation: minor clarifications
Timing: fix mbedtls_set_alarm(0) on Unix/POSIX
1. Surround the generate keys with
`#if ! defined(MBEDTLS_CMAC_ALT) || defined(MBEDTLS_SELF_TEST)`
to resolve build issue when `MBEDTLS_SELF_TEST` is defined for
alternative CMAC as well
2. Update ChangeLog
Increase the duration of the self test, otherwise it tends to fail on
a busy machine even with the recently upped tolerance. But run the
loop only once, it's enough for a simple smoke test.
mbedtls_timing_self_test fails annoyingly often when running on a busy
machine such as can be expected of a continous integration system.
Increase the tolerances in the delay test, to reduce the chance of
failures that are only due to missing a deadline on a busy machine.
Print some not-very-nice-looking but helpful diagnosis information if
the timing selftest fails. Since the failures tend to be due to heavy
system load that's hard to reproduce, this information is necessary to
understand what's going on.
mbedtls_timing_get_timer with reset=1 is called both to initialize a
timer object and to reset an already-initialized object. In an
initial call, the content of the data structure is indeterminate, so
the code should not read from it. This could crash if signed overflows
trap, for example.
As a consequence, on reset, we can't return the previously elapsed
time as was previously done on Windows. Return 0 as was done on Unix.
The POSIX/Unix implementation of mbedtls_set_alarm did not set the
mbedtls_timing_alarmed flag when called with 0, which was inconsistent
with what the documentation implied and with the Windows behavior.
* restricted/pr/403:
Correct record header size in case of TLS
Don't allocate space for DTLS header if DTLS is disabled
Improve debugging output
Adapt ChangeLog
Add run-time check for handshake message size in ssl_write_record
Add run-time check for record content size in ssl_encrypt_buf
Add compile-time checks for size of record content and payload
* development:
Don't split error code description across multiple lines
Register new error code in error.h
Move deprecation to separate section in ChangeLog
Extend scope of ERR_RSA_UNSUPPORTED_OPERATION error code
Adapt RSA test suite
Adapt ChangeLog
Deprecate usage of RSA primitives with wrong key type
* restricted/pr/397:
Don't split error code description across multiple lines
Register new error code in error.h
Move deprecation to separate section in ChangeLog
Extend scope of ERR_RSA_UNSUPPORTED_OPERATION error code
Adapt RSA test suite
Adapt ChangeLog
Deprecate usage of RSA primitives with wrong key type
In a previous PR (Fix heap corruption in implementation of truncated HMAC
extension #425) the place where MAC is computed was changed from the end of
the SSL I/O buffer to a local buffer (then (part of) the content of the local
buffer is either copied to the output buffer of compare to the input buffer).
Unfortunately, this change was made only for TLS 1.0 and later, leaving SSL
3.0 in an inconsistent state due to ssl_mac() still writing to the old,
hard-coded location, which, for MAC verification, resulted in later comparing
the end of the input buffer (containing the computed MAC) to the local buffer
(uninitialised), most likely resulting in MAC verification failure, hence no
interop (even with ourselves).
This commit completes the move to using a local buffer by using this strategy
for SSL 3.0 too. Fortunately ssl_mac() was static so it's not a problem to
change its signature.
Fix missing definition of mbedtls_zeroize when MBEDTLS_FS_IO is
disabled in the configuration.
Introduced by e7707228b4
Merge remote-tracking branch 'upstream-public/pr/1062' into development
In case truncated HMAC must be used but the Mbed TLS peer hasn't been updated
yet, one can use the compile-time option MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT to
temporarily fall back to the old, non-compliant implementation of the truncated
HMAC extension.
The truncated HMAC extension as described in
https://tools.ietf.org/html/rfc6066.html#section-7 specifies that when truncated
HMAC is used, only the HMAC output should be truncated, while the HMAC key
generation stays unmodified. This commit fixes Mbed TLS's behavior of also
truncating the key, potentially leading to compatibility issues with peers
running other stacks than Mbed TLS.
Details:
The keys for the MAC are pieces of the keyblock that's generated from the
master secret in `mbedtls_ssl_derive_keys` through the PRF, their size being
specified as the size of the digest used for the MAC, regardless of whether
truncated HMAC is enabled or not.
/----- MD size ------\ /------- MD size ----\
Keyblock +----------------------+----------------------+------------------+---
now | MAC enc key | MAC dec key | Enc key | ...
(correct) +----------------------+----------------------+------------------+---
In the previous code, when truncated HMAC was enabled, the HMAC keys
were truncated to 10 bytes:
/-10 bytes-\ /-10 bytes-\
Keyblock +-------------+-------------+------------------+---
previously | MAC enc key | MAC dec key | Enc key | ...
(wrong) +-------------+-------------+------------------+---
The reason for this was that a single variable `transform->maclen` was used for
both the keysize and the size of the final MAC, and its value was reduced from
the MD size to 10 bytes in case truncated HMAC was negotiated.
This commit fixes this by introducing a temporary variable `mac_key_len` which
permanently holds the MD size irrespective of the presence of truncated HMAC,
and using this temporary to obtain the MAC key chunks from the keyblock.
Previously, MAC validation for an incoming record proceeded as follows:
1) Make a copy of the MAC contained in the record;
2) Compute the expected MAC in place, overwriting the presented one;
3) Compare both.
This resulted in a record buffer overflow if truncated MAC was used, as in this
case the record buffer only reserved 10 bytes for the MAC, but the MAC
computation routine in 2) always wrote a full digest.
For specially crafted records, this could be used to perform a controlled write of
up to 6 bytes past the boundary of the heap buffer holding the record, thereby
corrupting the heap structures and potentially leading to a crash or remote code
execution.
This commit fixes this by making the following change:
1) Compute the expected MAC in a temporary buffer that has the size of the
underlying message digest.
2) Compare to this to the MAC contained in the record, potentially
restricting to the first 10 bytes if truncated HMAC is used.
A similar fix is applied to the encryption routine `ssl_encrypt_buf`.
* development: (30 commits)
update README file (#1144)
Fix typo in asn1.h
Improve leap year test names in x509parse.data
Correctly handle leap year in x509_date_is_valid()
Renegotiation: Add tests for SigAlg ext parsing
Parse Signature Algorithm ext when renegotiating
Minor style fix
config.pl get: be better behaved
config.pl get: don't rewrite config.h; detect write errors
Fixed "config.pl get" for options with no value
Fix typo and bracketing in macro args
Ensure failed test_suite output is sent to stdout
Remove use of GNU sed features from ssl-opt.sh
Fix typos in ssl-opt.sh comments
Add ssl-opt.sh test to check gmt_unix_time is good
Extend ssl-opt.h so that run_test takes function
Always print gmt_unix_time in TLS client
Restored note about using minimum functionality in makefiles
Note in README that GNU make is required
Fix changelog for ssl_server2.c usage fix
...
Fix the x509_get_subject_alt_name() function to not accept invalid
tags. The problem was that the ASN.1 class for tags consists of two
bits. Simply doing bit-wise and of the CONTEXT_SPECIFIC macro with the
input tag has the potential of accepting tag values 0x10 (private)
which would indicate that the certificate has an incorrect format.
This commit fixes a comparison of ssl_session->encrypt_then_mac against the
ETM-unrelated constant MBEDTLS_SSL_EXTENDED_MS_DISABLED. Instead,
MBEDTLS_SSL_ETM_DISABLED should be used.
The typo is has no functional effect since both constants have the same value 0.
Remove a check introduced in the previous buffer overflow fix with keys of
size 8N+1 which the subsequent fix for buffer start calculations made
redundant.
Added a changelog entry for the buffer start calculation fix.
For a key of size 8N+1, check that the first byte after applying the
public key operation is 0 (it could have been 1 instead). The code was
incorrectly doing a no-op check instead, which led to invalid
signatures being accepted. Not a security flaw, since you would need the
private key to craft such an invalid signature, but a bug nonetheless.
The check introduced by the previous security fix was off by one. It
fixed the buffer overflow but was not compliant with the definition of
PSS which technically led to accepting some invalid signatures (but
not signatures made without the private key).
I don't think this can cause a crash as the member accessed is in the
beginning of the context, so wouldn't be outside of valid memory if the actual
context was RSA.
Also, the mismatch will be caught later when checking signature, so the cert
chain will be rejected anyway.
Fix buffer overflow in RSA-PSS signature verification when the hash is
too large for the key size. Found by Seth Terashima, Qualcomm.
Added a non-regression test and a positive test with the smallest
permitted key size for a SHA-512 hash.
The function mbedtls_ecp_gen_keypair_base did not wipe the stack buffer used to
hold the private exponent before returning. This commit fixes this by not using
a stack buffer in the first place but instead calling mpi_fill_random directly
to acquire the necessary random MPI.
This commit modifies mpi_read_binary to always allocate the minimum number of
limbs required to hold the entire buffer provided to the function, regardless of
its content. Previously, leading zero bytes in the input data were detected and
used to reduce memory footprint and time, but this non-constant behavior turned
out to be non-tolerable for the cryptographic applications this function is used
for.
Previously, if `MBEDTLS_SSL_RENEGOTIATION` was disabled, incoming handshake
messages in `mbedtls_ssl_read` (expecting application data) lead to the
connection being closed. This commit fixes this, restricting the
`MBEDTLS_SSL_RENEGOTIATION`-guard to the code-paths responsible for accepting
renegotiation requests and aborting renegotiation attempts after too many
unexpected records have been received.
1) use `pk_get_rsapubkey` instead of reimplementing the parsing
2) rename the key files, according to their type and key size
3) comment in the data_files/Makefile hoe the keys were generated
4) Fix issue of failure parsing pkcs#1 DER format parsing, missed in previous commit
Signature algorithm extension was skipped when renegotiation was in
progress, causing the signature algorithm not to be known when
renegotiating, and failing the handshake. Fix removes the renegotiation
step check before parsing the extension.
As the optional RSA parameters DP, DQ and QP are effectively discarded (they are only considered for their length to
ensure that the key fills the entire buffer), it is not necessary to read them into separate MPI's.
The number of loop iterations per candidate in `mbedtls_deduce_primes` was off
by one. This commit corrects this and removes a toy non-example from the RSA
test suite, as it seems difficult to have the function fail on small values of N
even if D,E are corrupted.
Signature algorithm extension was skipped when renegotiation was in
progress, causing the signature algorithm not to be known when
renegotiating, and failing the handshake. Fix removes the renegotiation
step check before parsing the extension.
This commit splits off the RSA helper functions into separate headers and
compilation units to have a clearer separation of the public RSA interface,
intended to be used by end-users, and the helper functions which are publicly
provided only for the benefit of designers of alternative RSA implementations.
1) move the change into Features from Changes, in the changLog
2) Change the feature alternative configuration MBEDTLS_ECDH_ALT
definition to function alternative defintions
MBEDTLS_ECDH_COMPUTE_SHARED_ALT and MBEDTLS_ECDH_GEN_PUBLIC_ALT
1) update ChangLog to have new feature in Features instead of Changes
2) Change MBEDTLS_ECDSA_ALT to function specific alternative definitions:
MBEDTLS_ECDSA_SIGN_ALT, MBEDTLS_ECDSA_VERIFY_ALT and MBEDTLS_ECDSA_GENKEY_ALT
It is not necessary to pass a CSPRNG to `mbedtls_rsa_deduce_moduli`, as there
exist well-working static strategies, and even if a PRNG is preferred, a
non-secure one would be sufficient.
Further, the implementation is changed to use a static strategy for the choice
of candidates which according to some benchmarks even performs better than the
previous one using random candidate choices.
This commit reconciles the code path responsible for resending the
final DTLS handshake flight with the path for handling resending of
the other flights.
This commit restricts WANT_READ to indicate that no data is available on the
underlying transport. To signal the need for further processing - which was
previously also handled through this error code - a new internal error code
MBEDTLS_ERR_SSL_CONTINUE_PROCESSING is introduced.
DTLS records from previous epochs were incorrectly checked against the
current epoch transform's minimal content length, leading to the
rejection of entire datagrams. This commit fixed that and adapts two
test cases accordingly.
Internal reference: IOTSSL-1417
- Enhances the documentation of mbedtls_ssl_get_bytes_avail (return
the number of bytes left in the current application data record, if
there is any).
- Introduces a new public function mbedtls_ssl_check_pending for
checking whether any data in the internal buffers still needs to be
processed. This is necessary for users implementing event-driven IO
to decide when they can safely idle until they receive further
events from the underlying transport.
Give a note on the debugging output on the following occasions:
(1) The timer expires in mbedtls_ssl_fetch_input
(2) There's more than one records within a single datagram
Change ssl_parse_server_hello() so that the parsed first four random
bytes from the ServerHello message are printed by the TLS client as
a Unix timestamp regardless of whether MBEDTLS_DEBUG_C is defined. The
debug message will only be printed if debug_level is 3 or higher.
Unconditionally enabling the debug print enabled testing of this value.
Change ssl_parse_server_hello() so that the parsed first four random
bytes from the ServerHello message are printed by the TLS client as
a Unix timestamp regardless of whether MBEDTLS_DEBUG_C is defined. The
debug message will only be printed if debug_level is 3 or higher.
Unconditionally enabling the debug print enabled testing of this value.
Further, state explicitly that wrong key types need not be supported by alternative RSA implementations, and that those
may instead return the newly introduced error code MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION.
This commit returns to using constant macros instead of global variables for the DHM group constants. Further, macros
providing the binary encoding of the primes from RFC 3526 and RFC 7919 are added. The hex-string macros are deprecated.
This commit modifies the PKCS1 v1.5 signature verification function `mbedtls_rsa_rsassa_pkcs1_v15_verify` to prepare the
expected PKCS1-v1.5-encoded hash using the function also used by the signing routine `mbedtls_rsa_rsassa_pkcs1_v15_sign`
and comparing it to the provided byte-string afterwards. This comes at the benefits of (1) avoiding any error-prone
parsing, (2) removing the dependency of the RSA module on the ASN.1 parsing module, and (3) reducing code size.
This commit moves the code preparing PKCS1 v1.5 encoded hashes from `mbedtls_rsa_rsassa_pkcs1_v15_sign` to a separate
non-public function `rsa_rsassa_pkcs1_v15_encode`. This code-path will then be re-used by the signature verification function
`mbetls_rsa_rsassa_pkcs1_v15_verify` in a later commit.
Original intention was to be allowed to perform in-place operations like changing the byte-order before importing
parameters into an HSM. Now a copy is needed in this case, but there's no more danger of a user expecting the arguments
to be left untouched.
State explicitly that `pk_parse_pkcs8_undencrypted_der` and `pk_parse_key_pkcs8_encrypted_der` are not responsible for
zeroizing and freeing the provided key buffer.
This commit changes the implementation of `mbedtls_rsa_get_len` to return
`ctx->len` instead of always re-computing the modulus' byte-size via
`mbedtls_mpi_size`.
Although the variable ret was initialised to an error, the
MBEDTLS_MPI_CHK macro was overwriting it. Therefore it ended up being
0 whenewer the bignum computation was successfull and stayed 0
independently of the actual check.
This commit renames the test-only flag MBEDTLS_ENTROPY_HAVE_STRONG to ENTROPY_HAVE_STRONG to make it more transparent
that it's an internal flag, and also to content the testscript tests/scripts/check-names.pl which previously complained
about the macro occurring in a comment in `entropy.c` without being defined in a library file.
This commit removes extension-writing code for X.509 non-v3 certificates from
mbedtls_x509write_crt_der. Previously, even if no extensions were present an
empty sequence would have been added.
Fix compilation error on Mingw32 when `_TRUNCATE` is defined. Use
`_TRUNCATE` only if `__MINGW32__` not defined. Fix suggested by
Thomas Glanzmann and Nick Wilson on issue #355
* mbedtls-2.6: (27 commits)
Update version number to 2.6.0
Fix language in Changelog for clarity
Improve documentation of PKCS1 decryption functions
Fix style and missing item in ChangeLog
Add credit to Changelog to fix for #666
Fix naked call to time() with platform call
Fix ChangeLog for duplication after merge
Rename time and index parameter to avoid name conflict.
Correct comment
Adapt ChangeLog
Reliably zeroize sensitive data in AES sample application
Reliably zeroize sensitive data in Crypt-and-Hash sample application
Fix potential integer overflow parsing DER CRT
Fix potential integer overflow parsing DER CRL
Move the git scripts to correct path
Update after @sbutcher-arm comments
Fix slash direction for linux path
Add note for the git_hoos README file
Pre push hook script
Check return code of mbedtls_mpi_fill_random
...
The stack buffer used to hold the decrypted key in pk_parse_pkcs8_encrypted_der
was statically sized to 2048 bytes, which is not enough for DER encoded 4096bit
RSA keys.
This commit resolves the problem by performing the key-decryption in-place,
circumventing the introduction of another stack or heap copy of the key.
There are two situations where pk_parse_pkcs8_encrypted_der is invoked:
1. When processing a PEM-encoded encrypted key in mbedtls_pk_parse_key.
This does not need adaption since the PEM context used to hold the decoded
key is already constructed and owned by mbedtls_pk_parse_key.
2. When processing a DER-encoded encrypted key in mbedtls_pk_parse_key.
In this case, mbedtls_pk_parse_key calls pk_parse_pkcs8_encrypted_der with
the buffer provided by the user, which is declared const. The commit
therefore adds a small code paths making a copy of the keybuffer before
calling pk_parse_pkcs8_encrypted_der.
If CRT is not used, the helper fields CRT are not assumed to be present in the
RSA context structure, so do the verification directly in this case. If CRT is
used, verification could be done using CRT, but we're sticking to ordinary
verification for uniformity.
This commit adds the function mbedtls_rsa_validate_crt for validating a set of CRT parameters. The function
mbedtls_rsa_check_crt is simplified accordingly.
If rsm != NULL then the curve type has to be Short Weierstrass, as we don't
implement restartable Montgomery now. If and when we do, then it's better to
check for the subcontext only, and not for the curve type.
Exactly one of three ways will be used, so make that clear by using an
if 1 else if 2 else 3 structure.
While at it, don't initialize variables at declaration, just to make extra
sure they're properly initialized afterwards in all code paths.
As done by previous commits for ECC and ECDSA:
- use explicit state assignments rather than increment
- always place the state update right before the operation label
This will make it easier to add restart support for other operations later if
desired.
SSL-specific changes:
- remove useless states: when the last restartable operation on a message is
complete, ssl->state is incremented already, so we don't need any additional
state update: ecrs_state is only meant to complement ssl->state
- rename remaining states consistently as <message>_<operation>
- move some labels closer to the actual operation when possible (no assignment
to variables used after the label between its previous and current position)
Systematically assign state just before the next operation that may return,
rather that just after the previous one. This makes things more local. (For
example, previously precompute_comb() has to handle a state reset for
mul_comb_core(), a kind of coupling that's best avoided.)
Note that this change doesn't move the location of state updates relative
to any potential return point, which is all that matters.
Incrementing the state is error-prone as we can end up doing it too many times
(loops) or not enough (skipped branches), or just make programming mistakes
(eg. the state was incremented twice at the end, so it ended up with a value
not in the enum...)
This is the first step of the rework, the next one will rationalize where the
state assignments are done.
Primality testing is guarded by the configuration flag MBEDTLS_GENPRIME and used in the new RSA helper functions. This
commit adds a corresponding preprocessor directive.
The call would anyway check for pointer equality and return early, but it
doesn't hurt to save a function call, and also this follows more uniformly the
pattern that those two lines go together:
#if defined(MBEDTLS_ECP_RESTARTBLE)
if( rs_ctx != NULL && ...
Alternative RSA implementations can be provided by defining MBEDTLS_RSA_ALT in
config.h, defining an mbedtls_rsa_context struct in a new file rsa_alt.h and
re-implementing the RSA interface specified in rsa.h.
Through the previous reworkings, the adherence to the interface is the only
implementation obligation - in particular, implementors are free to use a
different layout for the RSA context structure.
Child was almost redundant as it's already saved in ver_chain, except it was
multiplexed to also indicate whether an operation is in progress. This commit
removes it and introduces an explicit state variable instead.
This state can be useful later if we start returning IN_PROGRESS at other
points than find_parent() (for example when checking CRL).
Note that the state goes none -> find_parent and stays there until the context
is free(), as it's only on the first call that nothing was in progress.
Some parts were already implicitly using this as the two ifdefs were nested,
and some others didn't, which resulted in compile errors in some configs. This
fixes those errors and saves a bit of code+RAM that was previously wasted when
ECP_RESTARTABLE was defined but ECDSA_C wasn't
Previously we kept the ecdsa context created by the PK layer for ECDSA
operations on ECKEY in the ecdsa_restart_ctx structure, which was wrong, and
caused by the fact that we didn't have a proper handling of restart
sub-contexts in the PK layer.
The fact that you needed to pass a pointer to mbedtls_ecdsa_restart_ctx (or
that you needed to know the key type of the PK context) was a breach of
abstraction.
Change the API (and callers) now, and the implementation will be changed in
the next commit.
Goals include:
- reducing the number of local variables in the main function (so that we
don't have to worry about saving/restoring them)
- reducing the number exit points in the main function, making it easier to
update ssl->state only right before we return
- more consistent naming with ecrs prefix for everything
- always check it enabled before touching the rest
- rm duplicated code in parse_server_hello()
For selection of test cases, see comments added in the commit.
It makes the most sense to test with chains using ECC only, so for the chain
of length 2 we use server10 -> int-ca3 -> int-ca2 and trust int-ca2 directly.
Note: server10.crt was created by copying server10_int3_int-ca2.crt and
manually truncating it to remove the intermediates. That base can now be used
to create derived certs (without or with a chain) in a programmatic way.
This is mainly for the benefit of SSL modules, which only supports restart in
a limited number of cases. In the other cases (ECDHE_PSK) it would currently
return ERR_ECP_IN_PROGRESS and the user would thus call ssl_handshake() again,
but the SSL code wouldn't handle state properly and things would go wrong in
possibly unexpected ways. This is undesirable, so it should be possible for
the SSL module to choose if ECDHE should behave the old or the new way.
Not that it also brings ECDHE more in line with the other modules which
already have that choice available (by passing a NULL or valid restart
context).
For RSA, we could either have the function return an error code like
NOT_IMPLEMENTED or just run while disregarding ecp_max_ops. IMO the second
option makes more sense, as otherwise the caller would need to check whether
the key is EC or RSA before deciding to call either sign() or
sign_restartable(), and having to do this kind of check feels contrary to the
goal of the PK layer.
Two different changes:
- the first one will allow us to store k in the restart context while
restarting the following ecp_mul() operation
- the second one is an simplification, unrelated to restartability, made
possible by the fact that ecp_gen_privkey() is now public
(Unrelated to restartable work, just noticed while staring at the code.)
Checking at the end is inefficient as we might give up when we just generated
a valid signature or key.
Otherwise code that uses these functions in other modules will have to do:
#if defined(MBEDTLS_ECP_RESTARTABLE)
ret = do_stuff( there, may, be, many, args );
#else
ret = do_stuff( their, may, be, namy, args, rs_ctx );
#fi
and there is a risk that the arg list will differ when code is updated, and
this might not be caught immediately by tests because this depends on a
config.h compile-time option which are harder to test.
Always declaring the restartable variants of the API functions avoids this
problem; the cost in ROM size should be negligible.
This will be useful for restartable ECDH and ECDSA. Currently they call
mbedtls_ecp_gen_keypair(); one could make that one restartable, but that means
adding its own sub-context, while ECDH and ECDSA (will) have their own
contexts already, so switching to this saves one extra context.
This should only be done in the top-level function.
Also, we need to know if we indeed are the top-level function or not: for
example, when mbedtls_ecp_muladd() calls mbedtls_ecp_mul(), the later should
not reset ops_done. This is handled by the "depth" parameter in the restart
context.
When a restartable function calls another restartable function, the current
ops_count needs to be shared to avoid either doing too many operations or
returning IN_PROGRESS uselessly. So it needs to be in the top-level context
rather than a specific sub-context.
This was intended to detect aborted operations, but now that case is handled
by the caller freeing the restart context.
Also, as the internal sub-context is managed by the callee, no need for the
caller to free/reset the restart context between successful calls.
Following discussion in the team, it was deemed preferable for the restart
context to be explicitly managed by the caller.
This commits in the first in a series moving in that directly: it starts by
only changing the public API, while still internally using the old design.
Future commits in that series will change to the new design internally.
The test function was simplified as it no longer makes sense to test for some
memory management errors since that responsibility shifted to the caller.
It's going to be convenient for each function that can generate a
MBEDTLS_ERR_ECP_IN_PROGRESS on its own (as opposed to just passing it around)
to have its own restart context that they can allocate and free as needed
independently of the restart context of other functions.
For example ecp_muladd() is going to have its own restart_muladd context that
in can managed, then when it calls ecp_mul() this will manage a restart_mul
context without interfering with the caller's context.
So, things need to be renames to avoid future name clashes.
From a user's perspective, you want a "basic operation" to take approximately
the same amount of time regardless of the curve size, especially since max_ops
is a global setting: otherwise if you pick a limit suitable for P-384 then
when you do an operation on P-256 it will return way more often than needed.
Said otherwise, a user is actually interested in actual running time, and we
do the API in terms of "basic ops" for practical reasons (no timers) but then
we should make sure it's a good proxy for running time.
Ok, so the original plan was to make mpi_inv_mod() the smallest block that
could not be divided. Updated plan is that the smallest block will be either:
- ecp_normalize_jac_many() (one mpi_inv_mod() + a number or mpi_mul_mpi()s)
- or the second loop in ecp_precompute_comb()
With default settings, the minimum non-restartable sequence is:
- for P-256: 222M
- for P-384: 341M
This is within a 2-3x factor of originally planned value of 120M. However,
that value can be approached, at the cost of some performance, by setting
ECP_WINDOW_SIZE (w below) lower than the default of 6. For example:
- w=4 -> 166M for any curve (perf. impact < 10%)
- w=2 -> 130M for any curve (perf. impact ~ 30%)
My opinion is that the current state with w=4 is a good compromise, and the
code complexity need to attain 120M is not warranted by the 1.4 factor between
that and the current minimum with w=4 (which is close to optimal perf).
This is the easy part: with the current steps, all information between steps
is passed via T which is already saved. Next we'll need to split at least the
first loop, and maybe calls to normalize_jac_many() and/or the second loop.
Separating main computation from filling of the auxiliary array makes things
clearer and easier to restart as we don't have to remember the in-progress
auxiliary array.
Previously there were only two states:
- T unallocated
- T allocated and valid
Now there are three:
- T unallocated
- T allocated and in progress
- T allocated and valid
Introduce new bool T_ok to distinguish the last two states.
Free it as soon as it's no longer needed, but as a backup free it in
ecp_group_free(), in case ecp_mul() is not called again after returning
ECP_IN_PROGRESS.
So far we only remember it when it's fully computed, next step is to be able
to compute it in multiple steps.
In case of argument change, freeing everything is not the most efficient
(wastes one free()+calloc()) but makes the code simpler, which is probably
more important here
We'll need to store MPIs and other things that allocate memory in this
context, so we need a place to free it. We can't rely on doing it before
returning from ecp_mul() as we might return MBEDTLS_ERR_ECP_IN_PROGRESS (thus
preserving the context) and never be called again (for example, TLS handshake
aborted for another reason). So, ecp_group_free() looks like a good place to
do this, if the restart context is part of struct ecp_group.
This means it's not possible to use the same ecp_group structure in different
threads concurrently, but:
- that's already the case (and documented) for other reasons
- this feature is precisely intended for environments that lack threading
An alternative option would be for the caller to have to allocate/free the
restart context and pass it explicitly, but this means creating new functions
that take a context argument, and putting a burden on the user.
The plan is to count basic operations as follows:
- call to ecp_add_mixed() -> 11
- call to ecp_double_jac() -> 8
- call to mpi_mul_mpi() -> 1
- call to mpi_inv_mod() -> 120
- everything else -> not counted
The counts for ecp_add_mixed() and ecp_double_jac() are based on the actual
number of calls to mpi_mul_mpi() they they make.
The count for mpi_inv_mod() is based on timing measurements on K64F and
LPC1768 boards, and are consistent with the usual very rough estimate of one
inversion = 100 multiplications. It could be useful to repeat that measurement
on a Cortex-M0 board as those have smaller divider and multipliers, so the
result could be a bit different but should be the same order of magnitude.
The documented limitation of 120 basic ops is due to the calls to mpi_inv_mod()
which are currently not interruptible nor planned to be so far.
This is the first step towards making verify_chain() iterative. While from a
readability point of view the current recursive version is fine, one of the
goals of this refactoring is to prepare for restartable ECC integration, which
will need the explicit stack anyway.
Besides avoiding near-duplication, this avoids having three generations of
certificate (child, parent, grandparent) in one function, with all the
off-by-one opportunities that come with it.
This also allows to simplify the signature of verify_child(), which will be
done in next commit.
This is from the morally 5th (and soon obsolete) invocation of this function
in verify_top().
Doing this badtime-skipping when we search for a parent in the provided chain
is a change of behaviour, but it's backwards-compatible: it can only cause us
to accept valid chains that we used to reject before. Eg if the peer has a
chain with two version of an intermediate certificate with different validity
periods, the first non valid and the second valid - such cases are probably
rare or users would have complained already, but it doesn't hurt to handle it
properly as it allows for more uniform code.
This may look like a behaviour change because one check has been added to the
function that was previously done in only one of the 3 call sites. However it
is not, because:
- for the 2 call sites in verify(), the test always succeeds as path_cnt is 0.
- for the call site in verify_child(), the same test was done later anyway in
verify_top()
There are 3 instance that were replaced, but 2 instances of variants of this
function exist and will be handled next (the extra parameter that isn't used
so far is in preparation for that):
- one in verify_child() where path_cnt constraint is handled too
- one in verify_top() where there is extra logic to skip parents that are
expired or future, but only if there are better parents to be found
This is a slight change of behaviour in that the previous condition was:
- same subject
- signature matches
while the new condition is:
- exact same certificate
However the documentation for mbedtls_x509_crt_verify() (note on trust_ca)
mentions the new condition, so code that respected the documentation will keep
working.
In addition, this is a bit faster as it doesn't check the self-signature
(which never needs to be checked for certs in the trusted list).
When we're looking for a parent, in trusted CAs, 'top' should be 1.
This only impacted which call site for verify_top() was chosen, and the error
was then fixed inside verify_top() by iterating over CAs again, this time
correctly setting 'top' to 1.
This is the beginning of a series of commits refactoring the chain
building/verification functions in order to:
- make it simpler to understand and work with
- prepare integration of restartable ECC
md() already checks for md_info == NULL. Also, in the future it might also
return other errors (eg hardware errors if acceleration is used), so it make
more sense to check its return value than to check for NULL ourselves and then
assume no other error can occur.
Also, currently, md_info == NULL can never happen except if the MD and OID modules
get out of sync, or if the user messes with members of the x509_crt structure
directly.
This commit does not change the current behaviour, which is to treat MD errors
the same way as a bad signature or no trusted root.
There were preprocessor directives in pk.c and pk_wrap.c that cheked
whether the bit length of size_t was greater than that of unsigned int.
However, the check relied on the MBEDTLS_HAVE_INT64 macro being defined
which is not directly related to size_t. This might result in errors in
some platforms. This change modifies the check to use the macros
SIZE_MAX and UINT_MAX instead making the code more robust.
As noted in #557, several functions use 'index' resp. 'time'
as parameter names in their declaration and/or definition, causing name
conflicts with the functions in the C standard library of the same
name some compilers warn about.
This commit renames the arguments accordingly.
Modify the function mbedtls_x509_csr_parse_der() so that it checks the
parsed CSR version integer before it increments the value. This prevents
a potential signed integer overflow, as these have undefined behaviour
in the C standard.
