From: Jerome Marchand <[email protected]>

commit 1c24de60e50fb19b94d94225458da17c720f0729 upstream.

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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Paul Gortmaker <[email protected]>
---
 kernel/groups.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/groups.c b/kernel/groups.c
index 2b45b2e..f0c2528 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;
-- 
1.7.3.3

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