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Merge pull request #8733 from ivq/gcm_ad_len_check

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Add back restriction on AD length of GCM
This commit is contained in:
Janos Follath 2024-02-05 13:33:58 +00:00 • committed by GitHub
commit 747bedb0b0
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3 changed files with 152 additions and 2 deletions
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15
library/gcm.c
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@ -354,9 +354,17 @@ int mbedtls_gcm_update_ad(mbedtls_gcm_context *ctx,
{
const unsigned char *p;
size_t use_len, offset;
uint64_t new_add_len;
/* IV is limited to 2^64 bits, so 2^61 bytes */
if ((uint64_t) add_len >> 61 != 0) {
/* AD is limited to 2^64 bits, ie 2^61 bytes
* Also check for possible overflow */
#if SIZE_MAX > 0xFFFFFFFFFFFFFFFFULL
if (add_len > 0xFFFFFFFFFFFFFFFFULL) {
return MBEDTLS_ERR_GCM_BAD_INPUT;
}
#endif
new_add_len = ctx->add_len + (uint64_t) add_len;
if (new_add_len < ctx->add_len || new_add_len >> 61 != 0) {
return MBEDTLS_ERR_GCM_BAD_INPUT;
}
@ -539,6 +547,9 @@ int mbedtls_gcm_finish(mbedtls_gcm_context *ctx,
(void) output_size;
*output_length = 0;
/* Total length is restricted to 2^39 - 256 bits, ie 2^36 - 2^5 bytes
* and AD length is restricted to 2^64 bits, ie 2^61 bytes so neither of
* the two multiplications would overflow. */
orig_len = ctx->len * 8;
orig_add_len = ctx->add_len * 8;