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>
This commit is contained in:
Jerome Marchand 2010-09-09 16:37:59 -07:00 committed by Linus Torvalds
parent 94131e174f
commit 1c24de60e5

View File

@ -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;