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.
diff --git a/library/x509_csr.c b/library/x509_csr.c
index f92b66c..26a06db 100644
--- a/library/x509_csr.c
+++ b/library/x509_csr.c
@@ -168,14 +168,14 @@
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
*/