When checking the trailing checksum hash of a .idx file, we pass the
whole buffer (minus the trailing hash) into a single call to
the_hash_algo->update_fn(). But we cast it to an "unsigned int". This
comes from c4001d92be (Use off_t when we really mean a file offset.,
2007-03-06). That commit started storing the index_size variable as an
off_t, but our mozilla-sha1 implementation from the time was limited to
a smaller size. Presumably the cast was a way of annotating that we
expected .idx files to be small, and so we didn't need to loop (as we do
for arbitrarily-large .pack files). Though as an aside it was still
wrong, because the mozilla function actually took a signed int.
These days our hash-update functions are defined to take a size_t, so we
can pass the whole buffer in directly. The cast is actually causing a
buggy truncation!
While we're here, though, let's drop the confusing off_t variable in the
first place. We're getting the size not from the filesystem anyway, but
from p->index_size, which is a size_t. In fact, we can make the code a
bit more readable by dropping our local variable duplicating
p->index_size, and instead have one that stores the size of the actual
index data, minus the trailing hash.
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
pack-check.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/pack-check.c b/pack-check.c
index db3adf8781..4b089fe8ec 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -164,22 +164,22 @@ static int verify_packfile(struct repository *r,
int verify_pack_index(struct packed_git *p)
{
- off_t index_size;
+ size_t len;
const unsigned char *index_base;
git_hash_ctx ctx;
unsigned char hash[GIT_MAX_RAWSZ];
int err = 0;
if (open_pack_index(p))
return error("packfile %s index not opened", p->pack_name);
- index_size = p->index_size;
index_base = p->index_data;
+ len = p->index_size - the_hash_algo->rawsz;
/* Verify SHA1 sum of the index file */
the_hash_algo->init_fn(&ctx);
- the_hash_algo->update_fn(&ctx, index_base, (unsigned int)(index_size - the_hash_algo->rawsz));
+ the_hash_algo->update_fn(&ctx, index_base, len);
the_hash_algo->final_fn(hash, &ctx);
- if (!hasheq(hash, index_base + index_size - the_hash_algo->rawsz))
+ if (!hasheq(hash, index_base + len))
err = error("Packfile index for %s hash mismatch",
p->pack_name);
return err;
--
2.29.2.705.g306f91dc4e
