Prevent signed integer overflow in CSR parsing

Modify the function mbedtls_x509_csr_parse_der() so that it checks the
parsed CSR version integer before it increments the value. This prevents
a potential signed integer overflow, as these have undefined behaviour
in the C standard.
This commit is contained in:
Andres AG 2017-02-17 13:54:43 +00:00 committed by Simon Butcher
parent 1f06d9bac7
commit b322be507b
2 changed files with 10 additions and 6 deletions

View File

@ -17,6 +17,13 @@ Bugfix
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
* Fix a potential integer overflow in the version verification for DER
encoded X509 certificates. The overflow would enable maliciously
constructed certificates to bypass the certificate verification check.
* Fix potential integer overflow in the version verification for DER
encoded X509 CSRs. The overflow would enable maliciously constructed CSRs
to bypass the version verification check. Found by Peng Li/Yueh-Hsun Lin,
KNOX Security, Samsung Research America
= mbed TLS 2.1.8 branch released 2017-06-21
@ -131,9 +138,6 @@ Bugfix
digits. Found and fixed by Guido Vranken.
* Fix unlisted DES configuration dependency in some pkparse test cases. Found
by inestlerode. #555
* Fix a potential integer overflow in the version verification for DER
encoded X509 certificates. The overflow would enable maliciously
constructed certificates to bypass the certificate verification check.
= mbed TLS 2.1.6 branch released 2016-10-17

View File

@ -168,14 +168,14 @@ int mbedtls_x509_csr_parse_der( mbedtls_x509_csr *csr,
return( ret );
}
csr->version++;
if( csr->version != 1 )
if( csr->version != 0 )
{
mbedtls_x509_csr_free( csr );
return( MBEDTLS_ERR_X509_UNKNOWN_VERSION );
}
csr->version++;
/*
* subject Name
*/