From: Prince Kumar Maurya <princekumarmaurya06@gmail.com>
To: skhan@linuxfoundation.org, brauner@kernel.org,
dchinner@redhat.com, viro@zeniv.linux.org.uk,
chenzhongjin@huawei.com
Cc: Prince Kumar Maurya <princekumarmaurya06@gmail.com>,
linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
syzkaller-bugs@googlegroups.com, linux-fsdevel@vger.kernel.org,
syzbot+aad58150cbc64ba41bdc@syzkaller.appspotmail.com
Subject: [PATCH v4] fs/sysv: Null check to prevent null-ptr-deref bug
Date: Tue, 30 May 2023 18:31:41 -0700 [thread overview]
Message-ID: <20230531013141.19487-1-princekumarmaurya06@gmail.com> (raw)
In-Reply-To: <20230530-gefangen-ersonnen-d1f1b6eea903@brauner>
sb_getblk(inode->i_sb, parent) return a null ptr and taking lock on
that leads to the null-ptr-deref bug.
Reported-by: syzbot+aad58150cbc64ba41bdc@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=aad58150cbc64ba41bdc
Signed-off-by: Prince Kumar Maurya <princekumarmaurya06@gmail.com>
---
Change since v3: Added cleanup code for the branch[n].key on
failure code path.
fs/sysv/itree.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/sysv/itree.c b/fs/sysv/itree.c
index b22764fe669c..58d7f43a1371 100644
--- a/fs/sysv/itree.c
+++ b/fs/sysv/itree.c
@@ -145,6 +145,10 @@ static int alloc_branch(struct inode *inode,
*/
parent = block_to_cpu(SYSV_SB(inode->i_sb), branch[n-1].key);
bh = sb_getblk(inode->i_sb, parent);
+ if (!bh) {
+ sysv_free_block(inode->i_sb, branch[n].key);
+ break;
+ }
lock_buffer(bh);
memset(bh->b_data, 0, blocksize);
branch[n].bh = bh;
--
2.40.1
next prev parent reply other threads:[~2023-05-31 1:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-22 22:36 [syzbot] [fs?] KASAN: null-ptr-deref Write in get_block (2) syzbot
2023-05-28 1:25 ` [PATCH] Null check to prevent null-ptr-deref bug Prince Kumar Maurya
2023-05-28 6:58 ` Greg KH
2023-05-28 16:44 ` Prince Kumar Maurya
2023-05-28 16:46 ` Greg KH
2023-05-28 17:35 ` Prince Kumar Maurya
2023-05-28 17:51 ` Greg KH
2023-05-28 17:52 ` Greg KH
2023-05-28 18:44 ` [PATCH v3] fs/sysv: " Prince Kumar Maurya
2023-05-30 8:26 ` Christian Brauner
2023-05-30 14:59 ` Prince Kumar Maurya
2023-05-30 15:54 ` Christian Brauner
2023-05-31 1:31 ` Prince Kumar Maurya [this message]
2023-06-01 7:55 ` [PATCH v4] " Christian Brauner
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