From 1c24de60e50fb19b94d94225458da17c720f0729 Mon Sep 17 00:00:00 2001
From: Jerome Marchand <jmarchan@redhat.com>
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 <jmarchan@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
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;
--
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