eden-emu/mbedtls
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Protect setting of premaster_generated flag

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The flag is used for tracking if the premaster has
been succesfully generated. Note that when resuming
a session, the flag should not be used when trying to
notice if all the key generation/derivation has been done.
This commit is contained in:
Jarno Lamsa 2019-12-18 16:28:51 +02:00
parent 98801af26b
commit 67f0a1e833
3 changed files with 112 additions and 19 deletions
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14
library/ssl_srv.c
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@ -3978,7 +3978,9 @@ static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
unsigned char mask;
size_t i, peer_pmslen;
unsigned int diff;
volatile unsigned int pmscounter = 0;
ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_UNSET;
/* In case of a failure in decryption, the decryption may write less than
* 2 bytes of output, but we always read the first two bytes. It doesn't
* matter in the end because diff will be nonzero in that case due to
@ -4056,7 +4058,19 @@ static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
/* Set pms to either the true or the fake PMS, without
* data-dependent branches. */
for( i = 0; i < ssl->handshake->pmslen; i++ )
{
pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
pmscounter++;
}
if( pmscounter == ssl->handshake->pmslen )
{
mbedtls_platform_enforce_volatile_reads();
if( pmscounter == ssl->handshake->pmslen )
{
ssl->handshake->premaster_generated = MBEDTLS_SSL_FI_FLAG_SET;
}
}
return( 0 );
}