Fix missing bound check

This commit is contained in:
Manuel Pégourié-Gonnard 2014-11-25 17:41:50 +01:00 committed by Paul Bakker
parent f5f25b3a0d
commit 5cb4b31057
3 changed files with 16 additions and 0 deletions

View file

@ -9,6 +9,10 @@ Features
* Add support for Extended Master Secret (draft-ietf-tls-session-hash)
* Add support for Encrypt-then-MAC (RFC 7366)
Bugfix
* Stack buffer overflow if ctr_drbg_update() is called with too large
add_len (found by Jean-Philippe Aumasson) (not triggerable remotely).
= PolarSSL 1.3.9 released 2014-10-20
Security
* Lowest common hash was selected from signature_algorithms extension in

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@ -188,6 +188,10 @@ int ctr_drbg_reseed( ctr_drbg_context *ctx,
* \param ctx CTR_DRBG context
* \param additional Additional data to update state with
* \param add_len Length of additional data
*
* \note If add_len is greater than CTR_DRBG_MAX_SEED_INPUT,
* only the first CTR_DRBG_MAX_SEED_INPUT bytes are used,
* the remaining ones are silently discarded.
*/
void ctr_drbg_update( ctr_drbg_context *ctx,
const unsigned char *additional, size_t add_len );

View file

@ -137,6 +137,9 @@ static int block_cipher_df( unsigned char *output,
int i, j;
size_t buf_len, use_len;
if( data_len > CTR_DRBG_MAX_SEED_INPUT )
return( POLARSSL_ERR_CTR_DRBG_INPUT_TOO_BIG );
memset( buf, 0, CTR_DRBG_MAX_SEED_INPUT + CTR_DRBG_BLOCKSIZE + 16 );
aes_init( &aes_ctx );
@ -256,6 +259,11 @@ void ctr_drbg_update( ctr_drbg_context *ctx,
if( add_len > 0 )
{
/* MAX_INPUT would be more logical here, but we have to match
* block_cipher_df()'s limits since we can't propagate errors */
if( add_len > CTR_DRBG_MAX_SEED_INPUT )
add_len = CTR_DRBG_MAX_SEED_INPUT;
block_cipher_df( add_input, additional, add_len );
ctr_drbg_update_internal( ctx, add_input );
}