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Commit baa60c66 authored by Prince Kumar Maurya's avatar Prince Kumar Maurya Committed by Greg Kroah-Hartman
Browse files

fs/sysv: Null check to prevent null-ptr-deref bug 



commit ea2b62f305893992156a798f665847e0663c9f41 upstream.

sb_getblk(inode->i_sb, parent) return a null ptr and taking lock on
that leads to the null-ptr-deref bug.

Reported-by: default avatar <syzbot+aad58150cbc64ba41bdc@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=aad58150cbc64ba41bdc


Signed-off-by: default avatarPrince Kumar Maurya <princekumarmaurya06@gmail.com>
Message-Id: <20230531013141.19487-1-princekumarmaurya06@gmail.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ad047663

fs/sysv/itree.c

+4 −0
Original line number Diff line number Diff line
@@ -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;