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).
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.
* restricted/mbedtls-2.1:
Remove obsolete macros from compat-1.3.h
Add fix for #667 to ChangeLog
Fix bug in threading sample implementation #667
Fix check-doxy-blocks.pl to run from root dir
RSA: wipe more stack buffers
RSA: wipe stack buffers
The test case was generated by modifying our signature code so that it
produces a 7-byte long padding (which also means garbage at the end, so it is
essential to check that the error that is detected first is indeed the
padding rather than the final length check).
The sliding window exponentiation algorithm is vulnerable to
side-channel attacks. As a countermeasure we add exponent blinding in
order to prevent combining the results of different measurements.
This commit handles the case when the Chinese Remainder Theorem is used
to accelerate the computation.
The sliding window exponentiation algorithm is vulnerable to
side-channel attacks. As a countermeasure we add exponent blinding in
order to prevent combining the results of different measurements.
This commits handles the case when the Chinese Remainder Theorem is NOT
used to accelerate computations.
The RSA private key functions rsa_rsaes_pkcs1_v15_decrypt and
rsa_rsaes_oaep_decrypt put sensitive data (decryption results) on the
stack. Wipe it before returning.
Thanks to Laurent Simon for reporting this issue.
The PKCS#1 standard says nothing about the relation between P and Q
but many libraries guarantee P>Q and mbed TLS did so too in earlier
versions.
This commit restores this behaviour.
Once the mutex is acquired, we must goto cleanup rather that return.
Since cleanup adjusts the return value, adjust that in test cases.
Also, at cleanup we don't want to overwrite 'ret', or we'll loose track of
errors.
see #257
* 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
* mbedtls-1.3:
Add missing depends in x509 programs
Simplify ifdef checks in programs/x509
Fix thread safety issue in RSA operations
Add test certificate for bitstring in DN
Add support for X.520 uniqueIdentifier
Accept bitstrings in X.509 names
The race was due to mpi_exp_mod storing a Montgomery coefficient in the
context (RM, RP, RQ).
The fix was verified with -fsanitize-thread using ssl_pthread_server and two
concurrent clients.
A more fine-grained fix should be possible, locking just enough time to check
if those values are OK and set them if not, rather than locking for the whole
mpi_exp_mod() operation, but it will be for later.
Note from future self: actually md_init_ctx will be re-introduced with the
same signature later, and a new function with the additional argument will be
added.
- more freedom for us to change it in the future
- enforces hygiene
- performance impact of making accessors no longer inline should really be
negligible
