util: silence -Wstringop-overread in SHA1

In function ‘SHA1Update’,
    inlined from ‘SHA1Pad’ at ../../../../../../../mesa/src/util/sha1/sha1.c:157:2,
    inlined from ‘SHA1Final’ at ../../../../../../../mesa/src/util/sha1/sha1.c:168:2:
../../../../../../../mesa/src/util/sha1/sha1.c:135:25: warning: ‘SHA1Transform’ reading 64 bytes from a region of size 1 [-Wstringop-overread]
  135 |                         SHA1Transform(context->state, (uint8_t *)&data[i]);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../../../../../../mesa/src/util/sha1/sha1.c:135:25: note: referencing argument 2 of type ‘const uint8_t[64]’ {aka ‘const unsigned char[64]’}
../../../../../../../mesa/src/util/sha1/sha1.c: In function ‘SHA1Final’:
../../../../../../../mesa/src/util/sha1/sha1.c:55:1: note: in a call to function ‘SHA1Transform’
   55 | SHA1Transform(uint32_t state[5], const uint8_t buffer[SHA1_BLOCK_LENGTH])
      | ^~~~~~~~~~~~~
In function ‘SHA1Update’,
    inlined from ‘SHA1Pad’ at ../../../../../../../mesa/src/util/sha1/sha1.c:159:3,
    inlined from ‘SHA1Final’ at ../../../../../../../mesa/src/util/sha1/sha1.c:168:2:
../../../../../../../mesa/src/util/sha1/sha1.c:135:25: warning: ‘SHA1Transform’ reading 64 bytes from a region of size 1 [-Wstringop-overread]
  135 |                         SHA1Transform(context->state, (uint8_t *)&data[i]);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../../../../../../mesa/src/util/sha1/sha1.c:135:25: note: referencing argument 2 of type ‘const uint8_t[64]’ {aka ‘const unsigned char[64]’}
../../../../../../../mesa/src/util/sha1/sha1.c: In function ‘SHA1Final’:
../../../../../../../mesa/src/util/sha1/sha1.c:55:1: note: in a call to function ‘SHA1Transform’
   55 | SHA1Transform(uint32_t state[5], const uint8_t buffer[SHA1_BLOCK_LENGTH])
      | ^~~~~~~~~~~~~
In function ‘SHA1Update’,
    inlined from ‘SHA1Pad’ at ../../../../../../../mesa/src/util/sha1/sha1.c:160:2,
    inlined from ‘SHA1Final’ at ../../../../../../../mesa/src/util/sha1/sha1.c:168:2:
../../../../../../../mesa/src/util/sha1/sha1.c:135:25: warning: ‘SHA1Transform’ reading 64 bytes from a region of size 8 [-Wstringop-overread]
  135 |                         SHA1Transform(context->state, (uint8_t *)&data[i]);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../../../../../../mesa/src/util/sha1/sha1.c:135:25: note: referencing argument 2 of type ‘const uint8_t[64]’ {aka ‘const unsigned char[64]’}
../../../../../../../mesa/src/util/sha1/sha1.c: In function ‘SHA1Final’:
../../../../../../../mesa/src/util/sha1/sha1.c:55:1: note: in a call to function ‘SHA1Transform’
   55 | SHA1Transform(uint32_t state[5], const uint8_t buffer[SHA1_BLOCK_LENGTH])
      | ^~~~~~~~~~~~~

Reaching this code is impossible for the SHA1Update() calls in SHA1Pad().
Use assume() to inform the compiler of this.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34785>
This commit is contained in:
Rhys Perry 2025-05-01 12:33:12 +01:00 committed by Marge Bot
parent 2797f42451
commit 5629332dcf

View file

@ -17,6 +17,7 @@
#include <stdint.h>
#include <string.h>
#include "u_endian.h"
#include "macros.h"
#include "sha1.h"
#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
@ -131,8 +132,10 @@ SHA1Update(SHA1_CTX *context, const uint8_t *data, size_t len)
if ((j + len) > 63) {
(void)memcpy(&context->buffer[j], data, (i = 64-j));
SHA1Transform(context->state, context->buffer);
for ( ; i + 63 < len; i += 64)
for ( ; i + 63 < len; i += 64) {
assume(len >= 64);
SHA1Transform(context->state, (uint8_t *)&data[i]);
}
j = 0;
} else {
i = 0;