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From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org, Jeff Layton <jlayton@kernel.org>,
	David Howells <dhowells@redhat.com>,
	Hans de Goede <hdegoede@redhat.com>,
	Mike Marshall <hubcap@omnibond.com>,
	Joseph Qi <joseph.qi@linux.alibaba.com>,
	Bob Peterson <rpeterso@redhat.com>,
	Steve French <sfrench@samba.org>,
	Richard Weinberger <richard@nod.at>,
	Dominique Martinet <asmadeus@codewreck.org>,
	Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH v2 08/15] gfs2: be careful with inode refresh
Date: Sat, 13 Mar 2021 04:38:17 +0000	[thread overview]
Message-ID: <20210313043824.1283821-8-viro@zeniv.linux.org.uk> (raw)
In-Reply-To: <20210313043824.1283821-1-viro@zeniv.linux.org.uk>

1) gfs2_dinode_in() should *not* touch ->i_rdev on live inodes; even
"zero and immediately reread the same value from dinode" is broken -
have it overlap with ->release() of char device and you can get all
kinds of bogus behaviour.

2) mismatch on inode type on live inodes should be treated as fs
corruption rather than blindly setting ->i_mode.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/gfs2/glops.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 8e32d569c8bf..ef0b583c3417 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -394,18 +394,24 @@ static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
 	const struct gfs2_dinode *str = buf;
 	struct timespec64 atime;
 	u16 height, depth;
+	umode_t mode = be32_to_cpu(str->di_mode);
+	bool is_new = ip->i_inode.i_flags & I_NEW;
 
 	if (unlikely(ip->i_no_addr != be64_to_cpu(str->di_num.no_addr)))
 		goto corrupt;
+	if (unlikely(!is_new && inode_wrong_type(&ip->i_inode, mode)))
+		goto corrupt;
 	ip->i_no_formal_ino = be64_to_cpu(str->di_num.no_formal_ino);
-	ip->i_inode.i_mode = be32_to_cpu(str->di_mode);
-	ip->i_inode.i_rdev = 0;
-	switch (ip->i_inode.i_mode & S_IFMT) {
-	case S_IFBLK:
-	case S_IFCHR:
-		ip->i_inode.i_rdev = MKDEV(be32_to_cpu(str->di_major),
-					   be32_to_cpu(str->di_minor));
-		break;
+	ip->i_inode.i_mode = mode;
+	if (is_new) {
+		ip->i_inode.i_rdev = 0;
+		switch (mode & S_IFMT) {
+		case S_IFBLK:
+		case S_IFCHR:
+			ip->i_inode.i_rdev = MKDEV(be32_to_cpu(str->di_major),
+						   be32_to_cpu(str->di_minor));
+			break;
+		}
 	}
 
 	i_uid_write(&ip->i_inode, be32_to_cpu(str->di_uid));
-- 
2.11.0


  parent reply	other threads:[~2021-03-13  4:41 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <YDqRThxQOVQO9uOx@zeniv-ca.linux.org.uk>
2021-03-13  4:35 ` [RFC][PATCHSET v2] inode type bits fixes Al Viro
2021-03-13  4:38   ` [PATCH v2 01/15] new helper: inode_wrong_type() Al Viro
2021-03-13  4:38     ` [PATCH v2 02/15] ceph: fix up error handling with snapdirs Al Viro
2021-03-13  4:38     ` [PATCH v2 03/15] ceph: don't allow type or device number to change on non-I_NEW inodes Al Viro
2021-03-13  4:38     ` [PATCH v2 04/15] afs: Fix updating of i_mode due to 3rd party change Al Viro
2021-03-13  4:38     ` [PATCH v2 05/15] vboxsf: don't allow to change the inode type Al Viro
2021-03-13  4:38     ` [PATCH v2 06/15] orangefs_inode_is_stale(): i_mode type bits do *not* form a bitmap Al Viro
2021-03-13  4:38     ` [PATCH v2 07/15] ocfs2_inode_lock_update(): make sure we don't change the type bits of i_mode Al Viro
2021-03-13  4:38     ` Al Viro [this message]
2021-03-13  4:38     ` [PATCH v2 09/15] do_cifs_create(): don't set ->i_mode of something we had not created Al Viro
2021-03-15 17:12       ` Jeff Layton
2021-03-13  4:38     ` [PATCH v2 10/15] cifs: have ->mkdir() handle race with another client sanely Al Viro
2021-03-15 17:08       ` Jeff Layton
2021-03-13  4:38     ` [PATCH v2 11/15] cifs: have cifs_fattr_to_inode() refuse to change type on live inode Al Viro
2021-03-15 17:13       ` Jeff Layton
2021-03-13  4:38     ` [PATCH v2 12/15] hostfs_mknod(): don't bother with init_special_inode() Al Viro
2021-03-13  4:38     ` [PATCH v2 13/15] openpromfs: don't do unlock_new_inode() until the new inode is set up Al Viro
2021-03-13  4:38     ` [PATCH v2 14/15] 9p: missing chunk of "fs/9p: Don't update file type when updating file attributes" Al Viro
2021-03-15 17:14       ` Jeff Layton
2021-03-13  4:38     ` [PATCH v2 15/15] spufs: fix bogosity in S_ISGID handling Al Viro
2021-03-15 17:19     ` [PATCH v2 01/15] new helper: inode_wrong_type() Jeff Layton

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