From 8c7e720a165baeaff3853d1cfe017f596381ae1d Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 11 Aug 2020 18:35:27 -0700 Subject: [PATCH] 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: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+a9ac3de1b5de5fb10efc@syzkaller.appspotmail.com Reported-by: syzbot+df958cf5688a96ad3287@syzkaller.appspotmail.com Signed-off-by: Eric Biggers Signed-off-by: Andrew Morton Cc: Alexander Viro Cc: Qiujun Huang Cc: Link: http://lkml.kernel.org/r/20200628060846.682158-3-ebiggers@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/minix/inode.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/minix/inode.c b/fs/minix/inode.c index 7cb5fd38eb149..2bca95abe8f49 100644 --- a/fs/minix/inode.c +++ b/fs/minix/inode.c @@ -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); -- 2.51.0