diff options
author | Matt Turner <mattst88@gmail.com> | 2017-11-23 10:41:34 -0800 |
---|---|---|
committer | Emil Velikov <emil.l.velikov@gmail.com> | 2017-11-27 18:33:40 +0000 |
commit | e4d964670a6d591352445e870d24454bf67d2970 (patch) | |
tree | fba6ee518f798b376565707c764d477127ec3410 | |
parent | bb8431aa3e9a53bc919f1b7f75dafa888a094f4b (diff) |
util: Fix disk_cache index calculation on big endian
The cache-test test program attempts to create a collision (using key_a
and key_a_collide) by making the first two bytes identical. The idea is
fine -- the shader cache wants to use the first four characters of a
SHA1 hex digest as the index.
The following program
unsigned char array[4] = {1, 2, 3, 4};
int *ptr = (int *)array;
for (int i = 0; i < 4; i++) {
printf("%02x", array[i]);
}
printf("\n");
printf("%08x\n", *ptr);
prints
01020304
04030201
on little endian, and
01020304
01020304
on big endian.
On big endian platforms reading the character array back as an int (as
is done in disk_cache.c) does not yield the same results as reading the
byte array.
To get the first four characters of the SHA1 hex digest when we mask
with CACHE_INDEX_KEY_MASK, we need to byte swap the int on big endian
platforms.
Bugzilla: https://bugs.freedesktop.org/103668
Bugzilla: https://bugs.gentoo.org/637060
Bugzilla: https://bugs.gentoo.org/636326
Fixes: 87ab26b2ab35 ("glsl: Add initial functions to implement an
on-disk cache")
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
(cherry picked from commit c690a7a8cdfb6425547bbb782020098405851194)
-rw-r--r-- | src/util/disk_cache.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c index fde6e2e0974..e95406565e4 100644 --- a/src/util/disk_cache.c +++ b/src/util/disk_cache.c @@ -1170,7 +1170,7 @@ void disk_cache_put_key(struct disk_cache *cache, const cache_key key) { const uint32_t *key_chunk = (const uint32_t *) key; - int i = *key_chunk & CACHE_INDEX_KEY_MASK; + int i = CPU_TO_LE32(*key_chunk) & CACHE_INDEX_KEY_MASK; unsigned char *entry; entry = &cache->stored_keys[i * CACHE_KEY_SIZE]; @@ -1189,7 +1189,7 @@ bool disk_cache_has_key(struct disk_cache *cache, const cache_key key) { const uint32_t *key_chunk = (const uint32_t *) key; - int i = *key_chunk & CACHE_INDEX_KEY_MASK; + int i = CPU_TO_LE32(*key_chunk) & CACHE_INDEX_KEY_MASK; unsigned char *entry; entry = &cache->stored_keys[i * CACHE_KEY_SIZE]; |