From: Jeff King Date: Sun, 4 Nov 2018 02:27:46 +0000 (-0400) Subject: midx: double-check large object write loop X-Git-Tag: v2.20.0-rc0~23^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=61b0fcbb64d00d52290d433c1e754c01740b3d19;p=thirdparty%2Fgit.git midx: double-check large object write loop The write_midx_large_offsets() function takes an array of object entries, the number of entries in the array (nr_objects), and the number of entries with large offsets (nr_large_offset). But we never actually use nr_objects; instead we keep walking down the array and counting down nr_large_offset until we've seen all of the large entries. This is correct, but we can be a bit more defensive. If there were ever a mismatch between nr_large_offset and the actual set of large-offset objects, we'd walk off the end of the array. Since we know the size of the array, we can use nr_objects to make sure we don't walk too far. Signed-off-by: Jeff King Reviewed-by: Derrick Stolee Signed-off-by: Junio C Hamano --- diff --git a/midx.c b/midx.c index 4fac0cd08a..ecd583666a 100644 --- a/midx.c +++ b/midx.c @@ -712,12 +712,18 @@ static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_nee static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset, struct pack_midx_entry *objects, uint32_t nr_objects) { - struct pack_midx_entry *list = objects; + struct pack_midx_entry *list = objects, *end = objects + nr_objects; size_t written = 0; while (nr_large_offset) { - struct pack_midx_entry *obj = list++; - uint64_t offset = obj->offset; + struct pack_midx_entry *obj; + uint64_t offset; + + if (list >= end) + BUG("too many large-offset objects"); + + obj = list++; + offset = obj->offset; if (!(offset >> 31)) continue;