block-sha1: take a size_t length parameter

peff · gitster · commit 9bb4542b8c1b · 2020-11-16T13:41:35.000-08:00
The block-sha1 implementation takes an "unsigned long" for the length of
a buffer to hash, but our hash algorithm wrappers take a size_t, as do
other implementations we support like openssl or sha1dc. On many
systems, including Linux, these two are equivalent, but they are not on
Windows (where only a "long long" is 64 bits). As a result, passing
large chunks to a single the_hash_algo-&gt;update_fn() would produce wrong
answers there.

Note that we don't need to update any other sizes outside of the
function interface. We store the cumulative size in a "long long" (which
we must do since we hash things bigger than 4GB, like packfiles, even on
32-bit platforms). And internally, we break that size_t len down into
64-byte blocks to feed into the guts of the algorithm.

Signed-off-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/block-sha1/sha1.c b/block-sha1/sha1.c
@@ -203,7 +203,7 @@ void blk_SHA1_Init(blk_SHA_CTX *ctx)
 	ctx->H[4] = 0xc3d2e1f0;
 }
 
-void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len)
+void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, size_t len)
 {
 	unsigned int lenW = ctx->size & 63;
 
diff --git a/block-sha1/sha1.h b/block-sha1/sha1.h
@@ -13,7 +13,7 @@ typedef struct {
 } blk_SHA_CTX;
 
 void blk_SHA1_Init(blk_SHA_CTX *ctx);
-void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *dataIn, unsigned long len);
+void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *dataIn, size_t len);
 void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx);
 
 #define platform_SHA_CTX	blk_SHA_CTX

Original file line number	Diff line number	Diff line change
`@@ -203,7 +203,7 @@ void blk_SHA1_Init(blk_SHA_CTX *ctx)`
`203`	`203`	`ctx->H[4] = 0xc3d2e1f0;`
`204`	`204`	`}`
`205`	`205`
`206`		`-void blk_SHA1_Update(blk_SHA_CTX ctx, const void data, unsigned long len)`
	`206`	`+void blk_SHA1_Update(blk_SHA_CTX ctx, const void data, size_t len)`
`207`	`207`	`{`
`208`	`208`	`unsigned int lenW = ctx->size & 63;`
`209`	`209`