linux-kernel - [PATCH] mm: Check for NULL return values from allocating functions

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-next>] [day] [month] [year] [list]

Message-Id: <1382021374-8285-1-git-send-email-lauraa@codeaurora.org>
Date:	Thu, 17 Oct 2013 07:49:34 -0700
From:	Laura Abbott <lauraa@...eaurora.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, Laura Abbott <lauraa@...eaurora.org>
Subject: [PATCH] mm: Check for NULL return values from allocating functions

A security audit revealed that several functions were not checking
return value of allocation functions. These allocations may return
NULL which may lead to NULL pointer dereferences and crashes or
security concerns. Fix this by properly checking the return value
and handling the error appropriately.

Signed-off-by: Laura Abbott <lauraa@...eaurora.org>
---
 fs/buffer.c |   17 +++++++++++------
 1 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 4d74335..b53f863 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1561,6 +1561,9 @@ void create_empty_buffers(struct page *page,
 	struct buffer_head *bh, *head, *tail;
 
 	head = alloc_page_buffers(page, blocksize, 1);
+	if (head == NULL)
+		return;
+
 	bh = head;
 	do {
 		bh->b_state |= b_state;
@@ -3008,16 +3011,18 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)
 	BUG_ON(buffer_unwritten(bh));
 
 	/*
-	 * Only clear out a write error when rewriting
-	 */
-	if (test_set_buffer_req(bh) && (rw & WRITE))
-		clear_buffer_write_io_error(bh);
-
-	/*
 	 * from here on down, it's all bio -- do the initial mapping,
 	 * submit_bio -> generic_make_request may further map this bio around
 	 */
 	bio = bio_alloc(GFP_NOIO, 1);
+	if (bio == NULL)
+		return -ENOMEM;
+
+	/*
+	 * Only clear out a write error when rewriting
+	 */
+	if (test_set_buffer_req(bh) && (rw & WRITE))
+		clear_buffer_write_io_error(bh);
 
 	bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
 	bio->bi_bdev = bh->b_bdev;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

--
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/