Commit Graph

232 Commits

Author SHA1 Message Date
Janos Follath
e344d0f6fc Add little endian export to Bignum
The function `mbedtls_mpi_write_binary()` writes big endian byte order,
but we need to be able to write little endian in some caseses. (For
example when handling keys corresponding to Montgomery curves.)

Used `echo xx | tac -rs ..` to transform the test data to little endian.
2019-02-22 15:41:31 +00:00
Janos Follath
171a7efd02 Add mbedtls_ecp_read_key
The private keys used in ECDH differ in the case of Weierstrass and
Montgomery curves. They have different constraints, the former is based
on big endian, the latter little endian byte order. The fundamental
approach is different too:
- Weierstrass keys have to be in the right interval, otherwise they are
  rejected.
- Any byte array of the right size is a valid Montgomery key and it
  needs to be masked before interpreting it as a number.

Historically it was sufficient to use mbedtls_mpi_read_binary() to read
private keys, but as a preparation to improve support for Montgomery
curves we add mbedtls_ecp_read_key() to enable uniform treatment of EC
keys.

For the masking the `mbedtls_mpi_set_bit()` function is used. This is
suboptimal but seems to provide the best trade-off at this time.
Alternatives considered:
- Making a copy of the input buffer (less efficient)
- removing the `const` constraint from the input buffer (breaks the api
and makes it less user friendly)
- applying the mask directly to the limbs (violates the api between the
modules and creates and unwanted dependency)
2019-02-22 15:39:03 +00:00
Janos Follath
a778a94b7d Add little endian import to Bignum
The function `mbedtls_mpi_read_binary()` expects big endian byte order,
but we need to be able to read from little endian in some caseses. (For
example when handling keys corresponding to Montgomery curves.)

Used `echo xx | tac -rs .. | tr [a-z] [A-Z]` to transform the test data
to little endian and `echo "ibase=16;xx" | bc` to convert to decimal.
2019-02-22 15:38:32 +00:00
Hanno Becker
23cfea01e8 Improve documentation of mbedtls_mpi_write_string() 2019-02-04 09:45:07 +00:00
Hanno Becker
c983c81a23 Fix 1-byte buffer overflow in mbedtls_mpi_write_string()
This can only occur for negative numbers. Fixes #2404.
2019-02-01 16:41:30 +00:00
Peter Kolbus
e6bcad3f79 Fix DEADCODE in mbedtls_mpi_exp_mod()
In mbedtls_mpi_exp_mod(), the limit check on wsize is never true when
MBEDTLS_MPI_WINDOW_SIZE is at least 6. Wrap in a preprocessor guard
to remove the dead code and resolve a Coverity finding from the
DEADCODE checker.

Change-Id: Ice7739031a9e8249283a04de11150565b613ae89
2019-01-31 19:37:51 -06:00
Jaeden Amero
91af329a55 Merge remote-tracking branch 'origin/pr/2214' into development 2019-01-30 15:08:25 +00:00
Jens Wiklander
f08aa3e023 fix memory leak in mpi_miller_rabin()
Fixes memory leak in mpi_miller_rabin() that occurs when the function has
failed to obtain a usable random 'A' 30 turns in a row.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
2019-01-17 13:30:57 +01:00
Hanno Becker
0e810b9648 Don't call memcpy with NULL pointer in mbedtls_mpi_read_binary()
mbedtls_mpi_read_binary() calls memcpy() with the source pointer being
the source pointer passed to mbedtls_mpi_read_binary(), the latter may
be NULL if the buffer length is 0 (and this happens e.g. in the ECJPAKE
test suite). The behavior of memcpy(), in contrast, is undefined when
called with NULL source buffer, even if the length of the copy operation
is 0.

This commit fixes this by explicitly checking that the source pointer is
not NULL before calling memcpy(), and skipping the call otherwise.
2019-01-03 17:13:11 +00:00
Hanno Becker
9f6d16ad79 Fix preprocessor macro existence check in bignum.c 2019-01-02 17:15:06 +00:00
Hanno Becker
6dab6200c6 Fix typo after rebase 2019-01-02 16:42:29 +00:00
Hanno Becker
5d91c0bbee Add missing macro existence check in byte swapping code in bignum.c 2019-01-02 11:38:14 +00:00
Hanno Becker
f872007782 Optimize mpi_bigendian_to_host() for speed and size
Use GCC / Clang builtins for byte swapping.
2019-01-02 11:38:14 +00:00
Hanno Becker
2be8a55f72 Change signature of mpi_bigendian_to_host() to reflect usage 2019-01-02 11:37:25 +00:00
Hanno Becker
da1655a48e Remove temporary stack-buffer from mbedtls_mpi_fill_random()
Context: The function `mbedtls_mpi_fill_random()` uses a temporary stack
buffer to hold the random data before reading it into the target MPI.

Problem: This is inefficient both computationally and memory-wise.
Memory-wise, it may lead to a stack overflow on constrained devices with
limited stack.

Fix: This commit introduces the following changes to get rid of the
temporary stack buffer entirely:

1. It modifies the call to the PRNG to output the random data directly
   into the target MPI's data buffer.

This alone, however, constitutes a change of observable behaviour:
The previous implementation guaranteed to interpret the bytes emitted by
the PRNG in a big-endian fashion, while rerouting the PRNG output into the
target MPI's limb array leads to an interpretation that depends on the
endianness of the host machine.
As a remedy, the following change is applied, too:

2. Reorder the bytes emitted from the PRNG within the target MPI's
   data buffer to ensure big-endian semantics.

Luckily, the byte reordering was already implemented as part of
`mbedtls_mpi_read_binary()`, so:

3. Extract bigendian-to-host byte reordering from
   `mbedtls_mpi_read_binary()` to a separate internal function
   `mpi_bigendian_to_host()` to be used by `mbedtls_mpi_read_binary()`
   and `mbedtls_mpi_fill_random()`.
2019-01-02 11:37:25 +00:00
Hanno Becker
f25ee7f79d Fix parameter validation for mbedtls_mpi_lsb()
The MPI_VALIDATE_RET() macro cannot be used for parameter
validation of mbedtls_mpi_lsb() because this function returns
a size_t.

Use the underlying MBEDTLS_INTERNAL_VALIDATE_RET() insteaed,
returning 0 on failure.

Also, add a test for this behaviour.
2018-12-19 16:51:50 +00:00
Hanno Becker
8ce11a323e Minor improvements to bignum module 2018-12-19 16:18:52 +00:00
Hanno Becker
54c91dd235 Remove double semicolon from bignum.c 2018-12-18 18:12:13 +00:00
Hanno Becker
73d7d79bc1 Implement parameter validation for MPI module 2018-12-18 18:12:13 +00:00
Simon Butcher
b9eb7866eb Merge remote-tracking branch 'restricted/pr/535' into development 2018-11-29 16:54:51 +00:00
Ron Eldor
a16fa297f7 Refactor mpi_write_hlp to not be recursive
Refactor `mpi_write_hlp()` to not be recursive, to fix stack overflows.
Iterate over the `mbedtls_mpi` division of the radix requested,
until it is zero. Each iteration, put the residue in the next LSB
of the output buffer. Fixes #2190
2018-11-27 10:34:36 +02:00
Gilles Peskine
11cdb0559e mbedtls_mpi_write_binary: don't leak the exact size of the number
In mbedtls_mpi_write_binary, avoid leaking the size of the number
through timing or branches, if possible. More precisely, if the number
fits in the output buffer based on its allocated size, the new code's
trace doesn't depend on the value of the number.
2018-11-20 17:09:27 +01:00
Darryl Green
e3f95ed25b Fix bias in random number generation in Miller-Rabin test
When a random number is generated for the Miller-Rabin primality test,
if the bit length of the random number is larger than the number being
tested, the random number is shifted right to have the same bit length.
This introduces bias, as the random number is now guaranteed to be
larger than 2^(bit length-1).

Changing this to instead zero all bits higher than the tested numbers
bit length will remove this bias and keep the random number being
uniformly generated.
2018-10-09 16:36:53 +01:00
Janos Follath
a0b67c2f3e Bignum: Deprecate mbedtls_mpi_is_prime()
When using a primality testing function the tolerable error rate depends
on the scheme in question, the required security strength and wether it
is used for key generation or parameter validation. To support all use
cases we need more flexibility than what the old API provides.
2018-10-09 16:36:53 +01:00
Janos Follath
da31fa137a Bignum: Fix prime validation vulnerability
The input distribution to primality testing functions is completely
different when used for generating primes and when for validating
primes. The constants used in the library are geared towards the prime
generation use case and are weak when used for validation. (Maliciously
constructed composite numbers can pass the test with high probability)

The mbedtls_mpi_is_prime() function is in the public API and although it
is not documented, it is reasonable to assume that the primary use case
is validating primes. The RSA module too uses it for validating key
material.
2018-10-09 16:36:53 +01:00
Janos Follath
b728c29114 Bignum: Remove dead code
Both variables affected by the code are overwritten before their next
read.
2018-10-09 16:33:27 +01:00
Janos Follath
f301d23ceb Bignum: Improve primality test for FIPS primes
The FIPS 186-4 RSA key generation prescribes lower failure probability
in primality testing and this makes key generation slower. We enable the
caller to decide between compliance/security and performance.

This python script calculates the base two logarithm of the formulas in
HAC Fact 4.48 and was used to determine the breakpoints and number of
rounds:

def mrpkt_log_2(k, t):
    if t <= k/9.0:
        return 3*math.log(k,2)/2+t-math.log(t,2)/2+4-2*math.sqrt(t*k)
    elif t <= k/4.0:
        c1 = math.log(7.0*k/20,2)-5*t
        c2 = math.log(1/7.0,2)+15*math.log(k,2)/4.0-k/2.0-2*t
        c3 = math.log(12*k,2)-k/4.0-3*t
        return max(c1, c2, c3)
    else:
        return math.log(1/7.0)+15*math.log(k,2)/4.0-k/2.0-2*t
2018-10-09 16:33:27 +01:00
Janos Follath
7c025a9f50 Generalize dh_flag in mbedtls_mpi_gen_prime
Setting the dh_flag to 1 used to indicate that the caller requests safe
primes from mbedtls_mpi_gen_prime. We generalize the functionality to
make room for more flags in that parameter.
2018-09-21 16:30:07 +01:00
Jaeden Amero
a331e0f0af Merge remote-tracking branch 'upstream-restricted/pr/421' into development-proposed 2018-05-04 14:39:24 +01:00
Andres Amaya Garcia
6698d2fc5c Fix style for mbedtls_mpi_zeroize() 2018-04-24 08:39:07 -05:00
Andres Amaya Garcia
1f6301b3c8 Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
Jethro Beekman
666892792d Generate primes according to FIPS 186-4
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.
2018-04-11 08:38:37 -07:00
Gilles Peskine
90a8b5219f Merge branch 'pr_1480' into development-proposed 2018-04-01 12:44:06 +02:00
Gilles Peskine
5bdb671404 Merge branch 'pr_403' into development-proposed 2018-03-22 21:34:15 +01:00
Gilles Peskine
4e4be7cf62 Optimize unnecessary zeorizing in mbedtls_mpi_copy
Based on a contribution by Alexey Skalozub
(https://github.com/ARMmbed/mbedtls/pull/405).
2018-03-21 16:29:03 +01:00
Hanno Becker
a3389ebb09 Merge branch 'development-restricted' into iotssl-1306-rsa-is-vulnerable-to-bellcore-glitch-attack 2018-03-06 11:55:21 +00:00
Hanno Becker
888071184c Zeroize stack before returning from mpi_fill_random 2017-10-18 12:41:30 +01:00
Hanno Becker
073c199224 Make mpi_read_binary time constant
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.
2017-10-17 15:17:27 +01:00
Hanno Becker
8d1dd1b5b9 Fix bug in mbedtls_mpi_exp_mod
Calling `mbedtls_mpi_exp_mod` with a freshly initialized exponent MPI `N`,
i.e. `N.p == NULL`, would lead to a null-pointer dereference.
2017-09-28 11:02:24 +01:00
Manuel Pégourié-Gonnard
db108ac944 Merge remote-tracking branch 'hanno/mpi_read_file_underflow' into development
* hanno/mpi_read_file_underflow:
  Fix potential stack underflow in mpi_read_file.
2017-06-08 19:48:03 +02:00
Hanno Becker
b2034b7785 Fix potential stack underflow in mpi_read_file.
When provided with an empty line, mpi_read_file causes a numeric
underflow resulting in a stack underflow. This commit fixes this and
adds some documentation to mpi_read_file.
2017-05-09 10:29:06 +01:00
Hanno Becker
4bcb4914c5 Abort modular inversion when modulus is one.
The modular inversion function hangs when provided with the modulus 1. This commit refuses this modulus with a BAD_INPUT error code. It also adds a test for this case.
2017-05-08 14:47:04 +01:00
Hanno Becker
a4af1c47d2 Correct sign in modular exponentiation algorithm.
The modular exponentiation function  handled the sign incorrectly. This commit fixes this and a test case which should have caught it.
2017-04-18 09:07:45 +01:00
Andres AG
d1cc7f6f34 Fix buffer overflow in mbedtls_mpi_write_string()
Fix a buffer overflow when writting a string representation of an MPI
number to a buffer in hexadecimal. The problem occurs because hex
digits are written in pairs and this is not accounted for in the
calculation of the required buffer size when the number of digits is
odd.
2017-03-02 21:34:21 +00:00
Simon Butcher
29176897a1 Adds additional casts to calloc calls
Casts added to allow compilation of the library as C++
2016-05-23 14:29:33 +01:00
Nicholas Wilson
91c68a5e15 Shut up a clang-analyzer warning
The function appears to be safe, since grow() is called with sensible
arguments in previous functions.  Ideally Clang would be clever enough to
realise this.  Even if N has size MBEDTLS_MPI_MAX_LIMBS, which will
cause the grow to fail, the affected lines in montmul won't be reached.
Having this sanity check can hardly hurt though.
2016-05-23 14:29:28 +01:00
Alexey Skalozub
e17a8da17e Rename MPI zeroize function to mbedtls_mpi_zeroize
Avoid naming confusion
2016-04-25 16:01:07 +01:00
Alexey Skalozub
3d53f41638 Faster mbedtls_zeroize for MPI
Writes in `sizeof(mbedtls_mpi_uint)` units perform faster than plain chars, also eliminates multiplication by `ciL`
2016-04-25 16:00:50 +01:00
Alexey Skalozub
8e75e68531 Remove redundant i increments
Doesn't matter performance-wise, but still...
2016-01-13 21:59:27 +02:00
Manuel Pégourié-Gonnard
e9c1b1a3bf Merge remote-tracking branch 'yanesca/iss309' into development
* yanesca/iss309:
  Improved on the previous fix and added a test case to cover both types of carries.
  Removed recursion from fix #309.
  Improved on the fix of #309 and extended the test to cover subroutines.
  Tests and fix added for #309 (inplace mpi doubling).
2016-01-07 13:22:27 +01:00
Simon Butcher
9803d07a63 Fix for MPI divide on MSVC
Resolves multiple platform issues when building bignum.c with Microsoft
Visual Studio.
2016-01-03 00:24:34 +00:00
Simon Butcher
f5ba04541e Fix for compiler warnings and style
Changes for C90 compliance, and style following review
2015-12-27 23:01:55 +00:00
Manuel Pégourié-Gonnard
1630888aa0 Fix two more compiler warnings
- declaration after statement
- always true comparison due to limited range of operand
2015-12-01 10:27:00 +01:00
Manuel Pégourié-Gonnard
e3e8edfa51 Fix potential integer overflow in prev. commit
Found by Clang's -Wshift-count-overflow
2015-12-01 09:34:36 +01:00
Simon Butcher
15b15d1361 Added integer divide by as separate function
Added 64bit integer divided by 32bit integer, with remainder
2015-11-26 19:35:03 +00:00
Janos Follath
6c92268093 Improved on the previous fix and added a test case to cover both types
of carries.
2015-10-30 17:50:12 +01:00
Janos Follath
3fc644f246 Removed recursion from fix #309. 2015-10-25 14:24:10 +01:00
Janos Follath
8483e28e21 Merge remote-tracking branch 'upstream/development' into iss309 2015-10-25 12:36:03 +01:00
Janos Follath
6cbacec3b3 Improved on the fix of #309 and extended the test to cover subroutines. 2015-10-25 12:31:27 +01:00
Janos Follath
044a86bde8 Tests and fix added for #309 (inplace mpi doubling). 2015-10-25 10:58:03 +01:00
Simon Butcher
334a87be0b Corrected URL/reference to MPI library 2015-10-14 22:56:44 +01:00
Manuel Pégourié-Gonnard
2d7083435d Fix references to non-standard SIZE_T_MAX
Turns out C99 doesn't define SIZE_T_MAX, so let's not use it.
2015-10-05 15:23:11 +01:00
Manuel Pégourié-Gonnard
58fb49531d Fix potential buffer overflow in mpi_read_string()
Found by Guido Vranken.

Two possible integer overflows (during << 2 or addition in BITS_TO_LIMB())
could result in far too few memory to be allocated, then overflowing the
buffer in the subsequent for loop.

Both integer overflows happen when slen is close to or greater than
SIZE_T_MAX >> 2 (ie 2^30 on a 32 bit system).

Note: one could also avoid those overflows by changing BITS_TO_LIMB(s << 2) to
CHARS_TO_LIMB(s >> 1) but the solution implemented looks more robust with
respect to future code changes.
2015-09-28 15:59:54 +02:00
Manuel Pégourié-Gonnard
37ff14062e Change main license to Apache 2.0 2015-09-04 14:21:07 +02:00
Manuel Pégourié-Gonnard
6fb8187279 Update date in copyright line 2015-07-28 17:11:58 +02:00
Manuel Pégourié-Gonnard
c0696c216b Rename mbedtls_mpi_msb to mbedtls_mpi_bitlen 2015-06-18 16:49:37 +02:00
Manuel Pégourié-Gonnard
f79b425226 Avoid in-out length parameter in bignum 2015-06-02 15:41:48 +01:00
Manuel Pégourié-Gonnard
6a8ca33fa5 Rename ERR_xxx_MALLOC_FAILED to ..._ALLOC_FAILED 2015-05-28 16:25:05 +02:00
Manuel Pégourié-Gonnard
7551cb9ee9 Replace malloc with calloc
- platform layer currently broken (not adapted yet)
- memmory_buffer_alloc too
2015-05-26 16:04:06 +02:00
Manuel Pégourié-Gonnard
da61ed3346 Merge branch 'mbedtls-1.3' into development
* mbedtls-1.3:
  Include changes from the 1.2 branch
  Remove unused headers in o_p_test
  Add countermeasure against cache-based lucky 13
  Make results of (ext)KeyUsage accessible
  Fix missing NULL check in MPI
  Fix detection of getrandom()
  Fix "make install" handling of symlinks
  Fix bugs in programs displaying verify flags

Conflicts:
	Makefile
	include/polarssl/ssl.h
	library/entropy_poll.c
	library/ssl_srv.c
	library/ssl_tls.c
	programs/test/o_p_test.c
	programs/test/ssl_cert_test.c
	programs/x509/cert_app.c
2015-04-30 10:38:44 +02:00
Manuel Pégourié-Gonnard
770b5e1e9e Fix missing NULL check in MPI 2015-04-29 17:02:01 +02:00
Manuel Pégourié-Gonnard
53c76c07de Merge branch 'mbedtls-1.3' into development
* commit 'ce60fbe':
  Fix potential timing difference with RSA PMS
  Update Changelog for recent merge
  Added more constant-time code and removed biases in the prime number generation routines.

Conflicts:
	library/bignum.c
	library/ssl_srv.c
2015-04-17 20:19:32 +02:00
Manuel Pégourié-Gonnard
aac657a1d3 Merge remote-tracking branch 'pj/development' into mbedtls-1.3
* pj/development:
  Added more constant-time code and removed biases in the prime number generation routines.
2015-04-15 14:12:59 +02:00
Manuel Pégourié-Gonnard
2cf5a7c98e The Great Renaming
A simple execution of tmp/invoke-rename.pl
2015-04-08 13:25:31 +02:00
Manuel Pégourié-Gonnard
fa8aebcbcc Fix a constness issue 2015-03-19 13:38:17 +00:00
Manuel Pégourié-Gonnard
35f1d7f0aa Update signature of mpi_mul_mpi() 2015-03-19 12:42:40 +00:00
Pascal Junod
b99183dfc6 Added more constant-time code and removed biases in the prime number generation routines. 2015-03-11 16:49:45 +01:00
Manuel Pégourié-Gonnard
7f8099773e Rename include directory to mbedtls 2015-03-10 11:23:56 +00:00
Manuel Pégourié-Gonnard
fe44643b0e Rename website and repository 2015-03-06 13:17:10 +00:00
Mansour Moufid
c531b4af3c Apply the semantic patch rm-malloc-cast.cocci.
for dir in library programs; do
        spatch --sp-file scripts/rm-malloc-cast.cocci --dir $dir \
        --in-place;
    done
2015-02-16 10:43:52 +00:00
Manuel Pégourié-Gonnard
d72704b0d5 Remove work-around for alleged compiler bug
It turns out the problem was with the way the reporter was invoking its
toolchain, not the toolchain itself.
2015-02-12 09:38:54 +00:00
Rich Evans
00ab47026b cleanup library and some basic tests. Includes, add guards to includes 2015-02-10 11:28:46 +00:00
Manuel Pégourié-Gonnard
860b51642d Fix url again 2015-01-28 17:12:07 +00:00
Manuel Pégourié-Gonnard
085ab040aa Fix website url to use https. 2015-01-23 11:06:27 +00:00
Manuel Pégourié-Gonnard
9698f5852c Remove maintainer line. 2015-01-23 10:59:00 +00:00
Manuel Pégourié-Gonnard
19f6b5dfaa Remove redundant "all rights reserved" 2015-01-23 10:54:00 +00:00
Manuel Pégourié-Gonnard
a658a4051b Update copyright 2015-01-23 09:55:24 +00:00
Manuel Pégourié-Gonnard
967a2a5f8c Change name to mbed TLS in the copyright notice 2015-01-22 14:28:16 +00:00
Manuel Pégourié-Gonnard
7f4ed67a97 Fix compile error with armcc in mpi_is_prime() 2014-10-15 22:06:46 +02:00
Paul Bakker
6c343d7d9a Fix mpi_write_string() to write "00" as hex output for empty MPI 2014-07-10 15:27:10 +02:00
Paul Bakker
66d5d076f7 Fix formatting in various code to match spacing from coding style 2014-06-17 17:06:47 +02:00
Paul Bakker
db20c10423 Add #endif comments for #endif more than 10 lines from #if / #else 2014-06-17 14:34:44 +02:00
Paul Bakker
d8bb82665e Fix code styling for return statements 2014-06-17 14:06:49 +02:00
Paul Bakker
3461772559 Introduce polarssl_zeroize() instead of memset() for zeroization 2014-06-14 16:46:03 +02:00
Paul Bakker
c37b0ac4b2 Fix typo in bignum.c 2014-05-01 14:19:23 +02:00
Paul Bakker
b9e4e2c97a Fix formatting: fix some 'easy' > 80 length lines 2014-05-01 14:18:25 +02:00
Paul Bakker
9af723cee7 Fix formatting: remove trailing spaces, #endif with comments (> 10 lines) 2014-05-01 13:03:14 +02:00
Paul Bakker
9bb04b6389 Removed redundant code in mpi_fill_random() 2014-05-01 09:47:02 +02:00
Manuel Pégourié-Gonnard
cef4ad2509 Adapt sources to configurable config.h name 2014-04-30 16:40:20 +02:00
Paul Bakker
33dc46b080 Fix bug with mpi_fill_random() on big-endian 2014-04-30 16:20:39 +02:00