Commit facb03dd authored by Eric Biggers's avatar Eric Biggers Committed by Linus Torvalds

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: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarAndrew 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.orgSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent da27e0a0
...@@ -468,6 +468,13 @@ static struct inode *V1_minix_iget(struct inode *inode) ...@@ -468,6 +468,13 @@ static struct inode *V1_minix_iget(struct inode *inode)
iget_failed(inode); iget_failed(inode);
return ERR_PTR(-EIO); 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; inode->i_mode = raw_inode->i_mode;
i_uid_write(inode, raw_inode->i_uid); i_uid_write(inode, raw_inode->i_uid);
i_gid_write(inode, raw_inode->i_gid); i_gid_write(inode, raw_inode->i_gid);
...@@ -501,6 +508,13 @@ static struct inode *V2_minix_iget(struct inode *inode) ...@@ -501,6 +508,13 @@ static struct inode *V2_minix_iget(struct inode *inode)
iget_failed(inode); iget_failed(inode);
return ERR_PTR(-EIO); 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; inode->i_mode = raw_inode->i_mode;
i_uid_write(inode, raw_inode->i_uid); i_uid_write(inode, raw_inode->i_uid);
i_gid_write(inode, raw_inode->i_gid); i_gid_write(inode, raw_inode->i_gid);
......
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