From cd25e15e57e68a6b18dc9323047fe9c68b99290b Mon Sep 17 00:00:00 2001
From: Joakim Sindholt <opensource@zhasha.com>
Date: Mon, 18 Mar 2024 12:22:31 +0100
Subject: [PATCH] fs/9p: only translate RWX permissions for plain 9P2000
Garbage in plain 9P2000's perm bits is allowed through, which causes it
to be able to set (among others) the suid bit. This was presumably not
the intent since the unix extended bits are handled explicitly and
conditionally on .u.
Signed-off-by: Joakim Sindholt <opensource@zhasha.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
---
fs/9p/vfs_inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index b01b1bbf24937..9612fdb563a3e 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -83,7 +83,7 @@ static int p9mode2perm(struct v9fs_session_info *v9ses,
int res;
int mode = stat->mode;
- res = mode & S_IALLUGO;
+ res = mode & 0777; /* S_IRWXUGO */
if (v9fs_proto_dotu(v9ses)) {
if ((mode & P9_DMSETUID) == P9_DMSETUID)
res |= S_ISUID;
--
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