pack-check.c::verify_packfile(): don't run SHA-1 update on huge data
Running the SHA1_Update() on the whole packfile in a single call
revealed an overflow problem we had in the SHA-1 implementation
on POWER architecture some time ago, which was fixed with commit
b47f509b (June 19, 2006). Other SHA-1 implementations may have
a similar problem.
The sliding mmap() series already makes chunked calls to
SHA1_Update(), so this patch itself will become moot when it
graduates to "master", but in the meantime, run the hash
function in smaller chunks to prevent possible future problems.
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/pack-check.c b/pack-check.c
index c0caaee..8e123b7 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -1,16 +1,18 @@
#include "cache.h"
#include "pack.h"
+#define BATCH (1u<<20)
+
static int verify_packfile(struct packed_git *p)
{
unsigned long index_size = p->index_size;
void *index_base = p->index_base;
SHA_CTX ctx;
unsigned char sha1[20];
- unsigned long pack_size = p->pack_size;
- void *pack_base;
struct pack_header *hdr;
int nr_objects, err, i;
+ unsigned char *packdata;
+ unsigned long datasize;
/* Header consistency check */
hdr = p->pack_base;
@@ -25,11 +27,19 @@
"while idx size expects %d", nr_objects,
num_packed_objects(p));
+ /* Check integrity of pack data with its SHA-1 checksum */
SHA1_Init(&ctx);
- pack_base = p->pack_base;
- SHA1_Update(&ctx, pack_base, pack_size - 20);
+ packdata = p->pack_base;
+ datasize = p->pack_size - 20;
+ while (datasize) {
+ unsigned long batch = (datasize < BATCH) ? datasize : BATCH;
+ SHA1_Update(&ctx, packdata, batch);
+ datasize -= batch;
+ packdata += batch;
+ }
SHA1_Final(sha1, &ctx);
- if (hashcmp(sha1, (unsigned char *)pack_base + pack_size - 20))
+
+ if (hashcmp(sha1, (unsigned char *)(p->pack_base) + p->pack_size - 20))
return error("Packfile %s SHA1 mismatch with itself",
p->pack_name);
if (hashcmp(sha1, (unsigned char *)index_base + index_size - 40))
