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Merge pull request #5829 from paul-elliott-arm/fix_ct_uninit_memory_access

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Fix uninitialised memory access in constant time functions
This commit is contained in:
Gilles Peskine
2022-06-01 11:42:51 +02:00
committed by GitHub
parent f940693960 5260ce27ed
commit 8399cccd2e
3 changed files with 21 additions and 2 deletions
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12
library/constant_time.c
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@@ -514,6 +514,12 @@ int mbedtls_ct_hmac( mbedtls_svc_key_id_t key,
PSA_CHK( psa_hash_update( &operation, add_data, add_data_len ) );
PSA_CHK( psa_hash_update( &operation, data, min_data_len ) );
/* Fill the hash buffer in advance with something that is
* not a valid hash (barring an attack on the hash and
* deliberately-crafted input), in case the caller doesn't
* check the return status properly. */
memset( output, '!', hash_size );
/* For each possible length, compute the hash up to that point */
for( offset = min_data_len; offset <= max_data_len; offset++ )
{
@@ -609,6 +615,12 @@ int mbedtls_ct_hmac( mbedtls_md_context_t *ctx,
MD_CHK( mbedtls_md_update( ctx, add_data, add_data_len ) );
MD_CHK( mbedtls_md_update( ctx, data, min_data_len ) );
/* Fill the hash buffer in advance with something that is
* not a valid hash (barring an attack on the hash and
* deliberately-crafted input), in case the caller doesn't
* check the return status properly. */
memset( output, '!', hash_size );
/* For each possible length, compute the hash up to that point */
for( offset = min_data_len; offset <= max_data_len; offset++ )
{