If Y was constructed through functions in this module, then Y->n == 0
iff Y->p == NULL. However we do not prevent filling mpi structures
manually, and zero may be represented with n=0 and p a valid pointer.
Most of the code can cope with such a representation, but for the
source of mbedtls_mpi_copy, this would cause an integer underflow.
Changing the test for zero from Y->p==NULL to Y->n==0 causes this case
to work at no extra cost.
In the 2.7 branch, test-ca.crt has all the components of its Subject name
encoded as PrintableString, because it's generated with our cert_write
program, and our code writes all components that way until Mbed TLS 2.14.
But the default RSA SHA-256 certificate, server2-sha256.crt, has the O and CN
components of its Issuer name encoded as UTF8String, because it was generated
with OpenSSL and that's what OpenSSL does, regardless of how those components
were encoded in the CA's Subject name.
This triggers some overly strict behaviour in some libraries, most notably NSS
and GnuTLS (of interest to us in ssl-opt.sh) which won't recognize the trusted
root as a possible parent for the presented certificate, see for example:
https://github.com/ARMmbed/mbedtls/issues/1033
Fortunately, we have at our disposal a version of test-ca.crt with encodings
matching the ones in server2-sha256.crt, in the file test-ca_utf8.crt. So
let's append that to gnutls-cli's list of trusted roots, so that it recognizes
certs signed by this CA but with the O and CN components as UTF8String.
Note: Since https://github.com/ARMmbed/mbedtls/pull/1641 was merged (in Mbed
TLS 2.14), we changed how we encode those components, so in the 2.16 branch,
cert_write generates test-ca.crt with encodings that matches the ones used by
openssl when generating server2-sha256.crt, so the issue of gnutls-cli
rejecting server2-sha256.crt is specific to the 2.7 branch.
The comment on TEST_SRV_CRT_RSA_SHA256 that it was
tests/data_files/server2-sha256.crt was a lie, the contents were actually
those of the mbedtls-2.16 version of the same file.
While it didn't have a noticeable impact on its own, it was confusing and
distracting while investigating an issue that cause gnutls-cli to not trust
the default RSA-SHA256 cert given test-ca.crt as a root, so worth fixing.
The splitting of this test into two versions depending on whether SHA-1 was
allowed by the server was a mistake in
5d2511c4d4 - the test has nothing to do with
SHA-1 in the first place, as the server doesn't request a certificate from
the client so it doesn't matter if the server accepts SHA-1 or not.
While the whole script makes (often implicit) assumptions about the version of
GnuTLS used, generally speaking it should work out of the box with the version
packaged on our reference testing platform, which is Ubuntu 16.04 so far.
With the update from Jan 8 2020 (3.4.10-4ubuntu1.6), the patches for rejecting
SHA-1 in certificate signatures were backported, so we should avoid presenting
SHA-1 signed certificates to a GnuTLS peer in ssl-opt.sh.
When mbedtls_x509_crt_parse_path() checks each object in the supplied path, it only processes regular files. This change makes it also accept a symlink to a file. Fixes#3005.
This was observed to be a problem on Fedora/CentOS/RHEL systems, where the ca-bundle in the default location is actually a symlink.
* origin/mbedtls-2.7:
Enable more test cases without MBEDTLS_MEMORY_DEBUG
More accurate test case description
Clarify that the "FATAL" message is expected
Note that mbedtls_ctr_drbg_seed() must not be called twice
Fix CTR_DRBG benchmark
Changelog entry for xxx_drbg_set_entropy_len before xxx_drbg_seed
CTR_DRBG: support set_entropy_len() before seed()
CTR_DRBG: Don't use functions before they're defined
HMAC_DRBG: support set_entropy_len() before seed()
The functions mbedtls_ctr_drbg_random() and
mbedtls_ctr_drbg_random_with_add() could return 0 if an AES function
failed. This could only happen with alternative AES
implementations (the built-in implementation of the AES functions
involved never fail), typically due to a failure in a hardware
accelerator.
Bug reported and fix proposed by Johan Uppman Bruce and Christoffer
Lauri, Sectra.
None of the test cases in tests_suite_memory_buffer_alloc actually
need MBEDTLS_MEMORY_DEBUG. Some have additional checks when
MBEDTLS_MEMORY_DEBUG but all are useful even without it. So enable
them all and #ifdef out the parts that require DEBUG.
The test case "Memory buffer small buffer" emits a message
"FATAL: verification of first header failed". In this test case, it's
actually expected, but it looks weird to see this message from a
passing test. Add a comment that states this explicitly, and modify
the test description to indicate that the failure is expected, and
change the test function name to be more accurate.
Fix#309
In ssl_parse_hello_verify_request, we read 3 bytes (version and cookie
length) without checking that there are that many bytes left in
ssl->in_msg. This could potentially read from memory outside of the
ssl->receive buffer (which would be a remotely exploitable
crash).
In ssl_parse_hello_verify_request, we print cookie_len bytes without
checking that there are that many bytes left in ssl->in_msg. This
could potentially log data outside the received message (not a big
deal) and could potentially read from memory outside of the receive
buffer (which would be a remotely exploitable crash).
* restricted/pr/666: (24 commits)
Add ChangeLog entry
mpi_lt_mpi_ct: fix condition handling
mpi_lt_mpi_ct: Add further tests
mpi_lt_mpi_ct: Fix test numbering
mpi_lt_mpi_ct perform tests for both limb size
ct_lt_mpi_uint: cast the return value explicitely
mbedtls_mpi_lt_mpi_ct: add tests for 32 bit limbs
mbedtls_mpi_lt_mpi_ct: simplify condition
Rename variable for better readability
mbedtls_mpi_lt_mpi_ct: Improve documentation
Make mbedtls_mpi_lt_mpi_ct more portable
Bignum: Document assumptions about the sign field
Add more tests for mbedtls_mpi_lt_mpi_ct
mpi_lt_mpi_ct test: hardcode base 16
Document ct_lt_mpi_uint
mpi_lt_mpi_ct: make use of unsigned consistent
ct_lt_mpi_uint: make use of biL
Change mbedtls_mpi_cmp_mpi_ct to check less than
mbedtls_mpi_cmp_mpi_ct: remove multiplications
Remove excess vertical space
...
This issue has been reported by Tuba Yavuz, Farhaan Fowze, Ken (Yihang) Bai,
Grant Hernandez, and Kevin Butler (University of Florida) and
Dave Tian (Purdue University).
In AES encrypt and decrypt some variables were left on the stack. The value
of these variables can be used to recover the last round key. To follow best
practice and to limit the impact of buffer overread vulnerabilities (like
Heartbleed) we need to zeroize them before exiting the function.
The corner case tests were designed for 32 and 64 bit limbs
independently and performed only on the target platform. On the other
platform they are not corner cases anymore, but we can still exercise
them.
The corner case tests were designed for 64 bit limbs and failed on 32
bit platforms because the numbers in the test ended up being stored in a
different number of limbs and the function (correctly) returnd an error
upon receiving them.
In the case of *ret we might need to preserve a 0 value throughout the
loop and therefore we need an extra condition to protect it from being
overwritten.
The value of done is always 1 after *ret has been set and does not need
to be protected from overwriting. Therefore in this case the extra
condition can be removed.
The code relied on the assumptions that CHAR_BIT is 8 and that unsigned
does not have padding bits.
In the Bignum module we already assume that the sign of an MPI is either
-1 or 1. Using this, we eliminate the above mentioned dependency.
