From: Nicolas Pitre Date: Tue, 24 Mar 2009 19:56:12 +0000 (-0400) Subject: avoid possible overflow in delta size filtering computation X-Git-Tag: v1.6.2.2~5^2~2^2~1 X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=720fe22d50a58e3308124ec7f5b0fa6c17be3d22;p=git.git avoid possible overflow in delta size filtering computation On a 32-bit system, the maximum possible size for an object is less than 4GB, while 64-bit systems may cope with larger objects. Due to this limitation, variables holding object sizes are using an unsigned long type (32 bits on 32-bit systems, or 64 bits on 64-bit systems). When large objects are encountered, and/or people play with large delta depth values, it is possible for the maximum allowed delta size computation to overflow, especially on a 32-bit system. When this occurs, surviving result bits may represent a value much smaller than what it is supposed to be, or even zero. This prevents some objects from being deltified although they do get deltified when a smaller depth limit is used. Fix this by always performing a 64-bit multiplication. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano --- diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c index fb5e14d56..84a13c7cc 100644 --- a/builtin-pack-objects.c +++ b/builtin-pack-objects.c @@ -1265,7 +1265,7 @@ static int try_delta(struct unpacked *trg, struct unpacked *src, max_size = trg_entry->delta_size; ref_depth = trg->depth; } - max_size = max_size * (max_depth - src->depth) / + max_size = (uint64_t)max_size * (max_depth - src->depth) / (max_depth - ref_depth + 1); if (max_size == 0) return 0;