Commit facb03dd authored Aug 11, 2020 by Eric Biggers Committed by Linus Torvalds Aug 12, 2020

fs/minix: don't allow getting deleted inodes



If an inode has no links, we need to mark it bad rather than allowing it
to be accessed.  This avoids WARNINGs in inc_nlink() and drop_nlink() when
doing directory operations on a fuzzed filesystem.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reported-by:  <syzbot+a9ac3de1b5de5fb10efc@syzkaller.appspotmail.com>
Reported-by:  <syzbot+df958cf5688a96ad3287@syzkaller.appspotmail.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Qiujun Huang <anenbupt@gmail.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200628060846.682158-3-ebiggers@kernel.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent da27e0a0

fs/minix/inode.c

+14 −0

Original line number	Diff line number	Diff line
		@@ -468,6 +468,13 @@ static struct inode V1_minix_iget(struct inode inode)
		iget_failed(inode);
		return ERR_PTR(-EIO);
		}
		if (raw_inode->i_nlinks == 0) {
		printk("MINIX-fs: deleted inode referenced: %lu\n",
		inode->i_ino);
		brelse(bh);
		iget_failed(inode);
		return ERR_PTR(-ESTALE);
		}
		inode->i_mode = raw_inode->i_mode;
		i_uid_write(inode, raw_inode->i_uid);
		i_gid_write(inode, raw_inode->i_gid);
		@@ -501,6 +508,13 @@ static struct inode V2_minix_iget(struct inode inode)
		iget_failed(inode);
		return ERR_PTR(-EIO);
		}
		if (raw_inode->i_nlinks == 0) {
		printk("MINIX-fs: deleted inode referenced: %lu\n",
		inode->i_ino);
		brelse(bh);
		iget_failed(inode);
		return ERR_PTR(-ESTALE);
		}
		inode->i_mode = raw_inode->i_mode;
		i_uid_write(inode, raw_inode->i_uid);
		i_gid_write(inode, raw_inode->i_gid);