linux-kernel - [PATCH 2/9 V2] idr: fix unexpected ID-removal when idr_remove(unallocated

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1397907496-5993-3-git-send-email-laijs@cn.fujitsu.com>
Date:	Sat, 19 Apr 2014 19:38:09 +0800
From:	Lai Jiangshan <laijs@...fujitsu.com>
To:	Tejun Heo <tj@...nel.org>, <linux-kernel@...r.kernel.org>
CC:	Lai Jiangshan <laijs@...fujitsu.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jean Delvare <jdelvare@...e.de>,
	Monam Agarwal <monamagarwal123@...il.com>,
	Jeff Layton <jlayton@...hat.com>,
	Andreas Gruenbacher <agruen@...bit.com>,
	Stephen Hemminger <stephen@...workplumber.org>
Subject: [PATCH 2/9 V2] idr: fix unexpected ID-removal when idr_remove(unallocated_id)

If unallocated_id = (ANY * idr_max(idp->layers) + existing_id) is passed
to idr_remove(). The existing_id will be removed unexpectedly.

The following test shows this unexpected id-removal:

static void test4(void)
{
	int id;
	DEFINE_IDR(test_idr);

	printk(KERN_INFO "Start test4\n");
	id = idr_alloc(&test_idr, (void *)1, 42, 43, GFP_KERNEL);
	BUG_ON(id != 42);
	idr_remove(&test_idr, 42 + IDR_SIZE);
	TEST_BUG_ON(idr_find(&test_idr, 42) != (void *)1);
	idr_destroy(&test_idr);
	printk(KERN_INFO "End of test4\n");
}

ida_remove() shares the similar problem.

It happens only when the caller tries to free an unallocated ID which
is the caller's fault. It is not a bug. But it is better to add
the proper check and complain rather than removing an existing_id silently.

Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com>
Acked-by: Tejun Heo <tj@...nel.org>
---
 lib/idr.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/lib/idr.c b/lib/idr.c
index 4df6792..c4afd94 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -562,6 +562,11 @@ void idr_remove(struct idr *idp, int id)
 	if (id < 0)
 		return;
 
+	if (id > idr_max(idp->layers)) {
+		idr_remove_warning(id);
+		return;
+	}
+
 	sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);
 	if (idp->top && idp->top->count == 1 && (idp->layers > 1) &&
 	    idp->top->ary[0]) {
@@ -1025,6 +1030,9 @@ void ida_remove(struct ida *ida, int id)
 	int n;
 	struct ida_bitmap *bitmap;
 
+	if (idr_id > idr_max(ida->idr.layers))
+		goto err;
+
 	/* clear full bits while looking up the leaf idr_layer */
 	while ((shift > 0) && p) {
 		n = (idr_id >> shift) & IDR_MASK;
-- 
1.7.4.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/