Use safe math to computer sizes.
The sizes are rounded via the expression: (cmpl + 7) / 8 which overflows if
cmpl is near to the type's maximum.  Instead we use the safe_math function to
computer this without any possibility of error.
#include "internal/cryptlib.h"
#include "internal/provider.h"
#include "internal/core.h"
+#include "internal/safe_math.h"
#include "crypto/evp.h"
#include "evp_local.h"
+OSSL_SAFE_MATH_SIGNED(int, int)
+
int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *ctx)
{
if (ctx == NULL)
@@ -517,7 +520,7 @@ static int evp_EncryptDecryptUpdate(EVP_CIPHER_CTX *ctx,
int i, j, bl, cmpl = inl;
if (EVP_CIPHER_CTX_test_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS))
- cmpl = (cmpl + 7) / 8;
+ cmpl = safe_div_round_up_int(cmpl, 8, NULL);
bl = ctx->cipher->block_size;
@@ -803,7 +806,7 @@ int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
b = ctx->cipher->block_size;
if (EVP_CIPHER_CTX_test_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS))
- cmpl = (cmpl + 7) / 8;
+ cmpl = safe_div_round_up_int(cmpl, 8, NULL);
if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
if (b == 1 && ossl_is_partially_overlapping(out, in, cmpl)) {
