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Commit 1c24de60 authored by Jerome Marchand's avatar Jerome Marchand Committed by Linus Torvalds
Browse files

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: default avatarJerome Marchand <jmarchan@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 94131e17

kernel/groups.c

+2 −3
Original line number Diff line number Diff line
@@ -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;