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authorMatt Turner <[email protected]>2017-11-23 10:41:34 -0800
committerMatt Turner <[email protected]>2017-11-25 12:30:46 -0800
commitc690a7a8cdfb6425547bbb782020098405851194 (patch)
tree707101df33c8cc55f58acaf20b62f8a2cf867c55 /src/util
parent513d7ffa23d42e96f831148fa13bf470087424c3 (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 <[email protected]>
Diffstat (limited to 'src/util')
-rw-r--r--src/util/disk_cache.c4
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];