Buffer overflow in hmac setup on known unsupported algorithm, with long input #254

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opened 2019-09-11 06:48:29 -05:00 by RonEld · 1 comment

RonEld commented

2019-09-11 06:48:29 -05:00

(Migrated from github.com)

Description

When calling psa_mac_sign_setup() for HMAC with a known but unsupported algorithm and a key that's longer than the block size, a buffer overflow occurs.
This happens in psa_hmac_setup_internal(), if psa_hash_setup() or psa_hash_update()fail, and thekey_length` is larger than PSA_HMAC_MAX_HASH_BLOCK_SIZE, because at the cleanup we do the following:

mbedtls_platform_zeroize( ipad, key_length );

Issue request type

[ ] Question
[ ] Enhancement
[x ] Bug

### Description  When calling `psa_mac_sign_setup()` for HMAC with a known but unsupported algorithm and a key that's longer than the block size, a buffer overflow occurs. This happens in `psa_hmac_setup_internal()`, if `psa_hash_setup() or `psa_hash_update()` fail, and the `key_length` is larger than PSA_HMAC_MAX_HASH_BLOCK_SIZE, because at the cleanup we do the following: ~~~ mbedtls_platform_zeroize( ipad, key_length ); ~~~ ### Issue request type  [ ] Question [ ] Enhancement [x ] Bug

ciarmcom commented

2019-09-11 07:25:05 -05:00

(Migrated from github.com)