From: Jori Koolstra Date: Tue, 4 Nov 2025 14:30:05 +0000 (+0100) Subject: Fix a drop_nlink warning in minix_rename X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=009a2ba40303cb1e3556c41233338e609ac509ea;p=thirdparty%2Flinux.git Fix a drop_nlink warning in minix_rename Syzbot found a drop_nlink warning that is triggered by an easy to detect nlink corruption. This patch adds sanity checks to minix_unlink and minix_rename to prevent the warning and instead return EFSCORRUPTED to the caller. The changes were tested using the syzbot reproducer as well as local testing. Signed-off-by: Jori Koolstra Link: https://patch.msgid.link/20251104143005.3283980-4-jkoolstra@xs4all.nl Reviewed-by: Jan Kara Reported-by: syzbot+a65e824272c5f741247d@syzkaller.appspotmail.com Closes: https://syzbot.org/bug?extid=a65e824272c5f741247d Signed-off-by: Christian Brauner --- diff --git a/fs/minix/namei.c b/fs/minix/namei.c index 68d2dd75b97f..263e4ba8b1c8 100644 --- a/fs/minix/namei.c +++ b/fs/minix/namei.c @@ -145,6 +145,11 @@ static int minix_unlink(struct inode * dir, struct dentry *dentry) struct minix_dir_entry * de; int err; + if (inode->i_nlink == 0) { + minix_error_inode(inode, "inode has corrupted nlink"); + return -EFSCORRUPTED; + } + de = minix_find_entry(dentry, &folio); if (!de) return -ENOENT; @@ -217,6 +222,17 @@ static int minix_rename(struct mnt_idmap *idmap, if (dir_de && !minix_empty_dir(new_inode)) goto out_dir; + err = -EFSCORRUPTED; + if (new_inode->i_nlink == 0 || (dir_de && new_inode->i_nlink != 2)) { + minix_error_inode(new_inode, "inode has corrupted nlink"); + goto out_dir; + } + + if (dir_de && old_dir->i_nlink <= 2) { + minix_error_inode(old_dir, "inode has corrupted nlink"); + goto out_dir; + } + err = -ENOENT; new_de = minix_find_entry(new_dentry, &new_folio); if (!new_de)