Messages in this thread Patch in this message | | | Date | Thu, 25 Feb 2010 16:10:27 +0100 | From | Roel Kluin <> | Subject | [PATCH] sha: prevent removal of memset as dead store in sha1_update() |
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Due to optimization A call to memset() may be removed as a dead store when the buffer is not used after its value is overwritten.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com> --- see http://cwe.mitre.org/data/slices/2000.html#14
checkpatch.pl, compile and sparse tested. Comments?
diff --git a/crypto/sha1_generic.c b/crypto/sha1_generic.c index 0416091..86de0da 100644 --- a/crypto/sha1_generic.c +++ b/crypto/sha1_generic.c @@ -49,8 +49,8 @@ static int sha1_update(struct shash_desc *desc, const u8 *data, src = data; if ((partial + len) > 63) { - u32 temp[SHA_WORKSPACE_WORDS]; - + u32 *temp = kzalloc(SHA_WORKSPACE_WORDS * sizeof(u32), + GFP_KERNEL); if (partial) { done = -partial; memcpy(sctx->buffer + partial, data, done + 64); @@ -64,6 +64,7 @@ static int sha1_update(struct shash_desc *desc, const u8 *data, } while (done + 63 < len); memset(temp, 0, sizeof(temp)); + kfree(temp); partial = 0; } memcpy(sctx->buffer + partial, src, len - done);
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