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| author |  Nicolas "Pixel" Noble <pixel@nobis-crew.org> | 2015-01-25 00:01:06 +0100 |
|---|---|---|
| committer | Nicolas "Pixel" Noble <pixel@nobis-crew.org> | 2015-01-25 00:03:51 +0100 |
| commit | 9074794e39c5ea4b555efc7c7b4870da46ca5b6f (patch) | |
| tree | 9a5557d570bfaceac64d50be5a38cebf31cd4277 /src | |
| parent | e2380338bfc9cec2f44877b3551d4e94490c1daa (diff) | |
Fixing an extremely suspicious-looking paradigm in murmur_hash.c
The current code is using the same variable name twice, k1, in two different scopes.
A cursory inspection of the code looks like one is trying to sneak a vulnerability by
masking off the reset of the k1 variable out of the loop; which is, in fact, what the
official algorithm does explicitely.
I guess this is a result of the C89-ization of the official algorithm, with the second
k1 variable usually defined AFTER the loop.
This change brings more sanity to the algorithm, making it much better-looking by
removing all ambiguity in what we're doing. The end result is exactly the same, but
at least we're explicit about it.
Diffstat (limited to 'src')
| -rw-r--r-- | src/core/support/murmur_hash.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/src/core/support/murmur_hash.c b/src/core/support/murmur_hash.c index 08b1eb80d8..892e360968 100644 --- a/src/core/support/murmur_hash.c +++ b/src/core/support/murmur_hash.c @@ -52,7 +52,7 @@ gpr_uint32 gpr_murmur_hash3(const void *key, size_t len, gpr_uint32 seed) { int i; gpr_uint32 h1 = seed; - gpr_uint32 k1 = 0; + gpr_uint32 k1; const gpr_uint32 c1 = 0xcc9e2d51; const gpr_uint32 c2 = 0x1b873593; @@ -62,7 +62,7 @@ gpr_uint32 gpr_murmur_hash3(const void *key, size_t len, gpr_uint32 seed) { /* body */ for (i = -nblocks; i; i++) { - gpr_uint32 k1 = GETBLOCK32(blocks, i); + k1 = GETBLOCK32(blocks, i); k1 *= c1; k1 = ROTL32(k1, 15); @@ -73,6 +73,8 @@ gpr_uint32 gpr_murmur_hash3(const void *key, size_t len, gpr_uint32 seed) { h1 = h1 * 5 + 0xe6546b64; } + k1 = 0; + /* tail */ switch (len & 3) { case 3: |