From 720fe22d50a58e3308124ec7f5b0fa6c17be3d22 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Tue, 24 Mar 2009 15:56:12 -0400 Subject: [PATCH] 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 --- builtin-pack-objects.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c index fb5e14d56e..84a13c7ccd 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;