Fix potential integer overflow parsing DER CRL

This patch prevents a potential signed integer overflow during the
CRL version verification checks.
This commit is contained in:
Andres AG 2017-03-01 15:14:30 +00:00 committed by Simon Butcher
parent 57501ef056
commit 26124be17a
2 changed files with 7 additions and 3 deletions

View file

@ -13,6 +13,10 @@ Bugfix
Found by redplait #590
* Add MPI_CHK to check for error value of mpi_fill_random.
Backported from a report and fix suggestion by guidovranken in #740
* Fix a potential integer overflow in the version verification for DER
encoded X509 CRLs. The overflow would enable maliciously constructed CRLs
to bypass the version verification check. Found by Peng Li/Yueh-Hsun Lin,
KNOX Security, Samsung Research America
= mbed TLS 1.3.20 branch released 2017-06-21

View file

@ -353,14 +353,14 @@ int x509_crl_parse_der( x509_crl *chain,
return( ret );
}
crl->version++;
if( crl->version > 2 )
if( crl->version < 0 || crl->version > 1 )
{
x509_crl_free( crl );
return( POLARSSL_ERR_X509_UNKNOWN_VERSION );
}
crl->version++;
if( ( ret = x509_get_sig_alg( &crl->sig_oid1, &sig_params1,
&crl->sig_md, &crl->sig_pk,
&crl->sig_opts ) ) != 0 )