fs/minix: don't allow getting deleted inodes

commit facb03dddec04e4aac1bb2139accdceb04deb1f3 upstream.

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: 1da177e4c3 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric Biggers 2020-08-11 18:35:27 -07:00 committed by Greg Kroah-Hartman
parent a5305f1199
commit 8c7e720a16

View File

@ -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);