linux-kernel - [PATCH 2/2] radix-tree: fix oops after radix_tree_iter

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-Id: <1454643648-10002-3-git-send-email-matthew.r.wilcox@intel.com>
Date:	Thu,  4 Feb 2016 22:40:48 -0500
From:	Matthew Wilcox <matthew.r.wilcox@...el.com>
To:	Konstantin Khlebnikov <koct9i@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Matthew Wilcox <matthew.r.wilcox@...el.com>,
	Hugh Dickins <hughd@...gle.com>, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH 2/2] radix-tree: fix oops after radix_tree_iter_retry

After calling radix_tree_iter_retry(), 'slot' will be set to NULL.
This can cause radix_tree_next_slot() to dereference the NULL pointer.
Check for a NULL pointer on entry to radix_tree_next_slot().

Reported-by: Konstantin Khlebnikov <koct9i@...il.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@...el.com>
---
 include/linux/radix-tree.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 3e488e2..9aa3afe 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -447,6 +447,9 @@ radix_tree_chunk_size(struct radix_tree_iter *iter)
 static __always_inline void **
 radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags)
 {
+	if (!slot)
+		return NULL;
+
 	if (flags & RADIX_TREE_ITER_TAGGED) {
 		iter->tags >>= 1;
 		if (likely(iter->tags & 1ul)) {
-- 
2.7.0.rc3