Fix integer overflows in buffer bound checks
Fix potential integer overflows in the following functions:
* mbedtls_md2_update() to be bypassed and cause
* mbedtls_cipher_update()
* mbedtls_ctr_drbg_reseed()
This overflows would mainly be exploitable in 32-bit systems and could
cause buffer bound checks to be bypassed.
diff --git a/library/cipher.c b/library/cipher.c
index a883438..e9e0b22 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -326,9 +326,9 @@
* If there is not enough data for a full block, cache it.
*/
if( ( ctx->operation == MBEDTLS_DECRYPT &&
- ilen + ctx->unprocessed_len <= block_size ) ||
+ ilen <= block_size - ctx->unprocessed_len ) ||
( ctx->operation == MBEDTLS_ENCRYPT &&
- ilen + ctx->unprocessed_len < block_size ) )
+ ilen < block_size - ctx->unprocessed_len ) )
{
memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input,
ilen );
