From 1c24de60e50fb19b94d94225458da17c720f0729 Mon Sep 17 00:00:00 2001 From: Jerome Marchand Date: Thu, 9 Sep 2010 16:37:59 -0700 Subject: [PATCH] kernel/groups.c: fix integer overflow in groups_search gid_t is a unsigned int. If group_info contains a gid greater than MAX_INT, groups_search() function may look on the wrong side of the search tree. This solves some unfair "permission denied" problems. Signed-off-by: Jerome Marchand Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/groups.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/groups.c b/kernel/groups.c index 53b1916c9492..253dc0f35cf4 100644 --- a/kernel/groups.c +++ b/kernel/groups.c @@ -143,10 +143,9 @@ int groups_search(const struct group_info *group_info, gid_t grp) right = group_info->ngroups; while (left < right) { unsigned int mid = (left+right)/2; - int cmp = grp - GROUP_AT(group_info, mid); - if (cmp > 0) + if (grp > GROUP_AT(group_info, mid)) left = mid + 1; - else if (cmp < 0) + else if (grp < GROUP_AT(group_info, mid)) right = mid; else return 1; -- 2.20.1