[PATCH 09/10] pack-revindex: use unsigned to store number of objects
- From
Jeff King <peff@peff.net>
- Date
- Jul 10, 2013, 11:50 UTC
- Message-ID
- <20130710115026.GI21963@sigill.intra.peff.net>
- In-Reply-To
- <20130710113447.GA20113@sigill.intra.peff.net>
A packfile may have up to 2^32-1 objects in it, so the "right" data type to use is uint32_t. We currently use a signed int, which means that we may behave incorrectly for packfiles with more than 2^31-1 objects on 32-bit systems.
Nobody has noticed because having 2^31 objects is pretty insane. The linux.git repo has on the order of 2^22 objects, which is hundreds of times smaller than necessary to trigger the bug.
Let's bump this up to an "unsigned". On 32-bit systems, this gives us the correct data-type, and on 64-bit systems, it is probably more efficient to use the native "unsigned" than a true uint32_t.
While we're at it, we can fix the binary search not to overflow in such a case if our unsigned is 32 bits.
Signed-off-by: Jeff King <peff@peff.net> --- I didn't look farther in the pack code to see if we have other problematic instances. So there may be others lurking, but these ones were close to the area I was working in.
pack-revindex.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/pack-revindex.c b/pack-revindex.c index 77a0465..1aa9754 100644 --- a/pack-revindex.c +++ b/pack-revindex.c @@ -72,8 +72,8 @@ static void create_pack_revindex(struct pack_revindex *rix) static void create_pack_revindex(struct pack_revindex *rix) { struct packed_git *p = rix->p; - int num_ent = p->num_objects; - int i; + unsigned num_ent = p->num_objects; + unsigned i; const char *index = p->index_data; rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1)); @@ -114,7 +114,7 @@ struct revindex_entry *find_pack_revindex(struct packed_git *p, off_t ofs) struct revindex_entry *find_pack_revindex(struct packed_git *p, off_t ofs) { int num; - int lo, hi; + unsigned lo, hi; struct pack_revindex *rix; struct revindex_entry *revindex; @@ -132,7 +132,7 @@ struct revindex_entry *find_pack_revindex(struct packed_git *p, off_t ofs) lo = 0; hi = p->num_objects + 1; do { - int mi = (lo + hi) / 2; + unsigned mi = lo + (hi - lo) / 2; if (revindex[mi].offset == ofs) { return revindex + mi; } else if (ofs < revindex[mi].offset)
-- 1.8.3.rc3.24.gec82cb9