From: Yuran Pereira <yuran.pereira@hotmail.com>
To: aivazian.tigran@gmail.com
Cc: Yuran Pereira <yuran.pereira@hotmail.com>,
syzbot+dc6ed11a88fb40d6e184@syzkaller.appspotmail.com,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [PATCH] bfs: Fix null pointer dereference in bfs_move_block
Date: Mon, 27 Nov 2023 05:09:05 +0530 [thread overview]
Message-ID: <GV1PR10MB65635AA7F497FC3EA6235261E8BEA@GV1PR10MB6563.EURPRD10.PROD.OUTLOOK.COM> (raw)
Syzkaller reported a NULL pointer dereference in
bfs_move_block.
sb_getblk may return a NULL pointer, and if unchecked
this can lead to a NULL pointer dereference. This is
the case in bfs_move_block, where `new` is not checked
before being dereferenced in the memcpy call.
This patch adds a propper check to the return value of
sb_getblk, stored in `new` and ensures that any previously
allocated resource, is deallocated before returning with
an appropriate error code if the `new` pointer is NULL.
Closes: https://syzkaller.appspot.com/bug?extid=dc6ed11a88fb40d6e184
Signed-off-by: Yuran Pereira <yuran.pereira@hotmail.com>
---
fs/bfs/file.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/fs/bfs/file.c b/fs/bfs/file.c
index adc2230079c6..8a97909b1484 100644
--- a/fs/bfs/file.c
+++ b/fs/bfs/file.c
@@ -38,7 +38,12 @@ static int bfs_move_block(unsigned long from, unsigned long to,
bh = sb_bread(sb, from);
if (!bh)
return -EIO;
+
new = sb_getblk(sb, to);
+ if (!new) {
+ bforget(bh);
+ return -ENOMEM;
+ }
memcpy(new->b_data, bh->b_data, bh->b_size);
mark_buffer_dirty(new);
bforget(bh);
--
2.25.1
reply other threads:[~2023-11-26 23:39 UTC|newest]
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