This is a note to let you know that I've just added the patch titled
fs: use consistent setgid checks in is_sxid()
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-use-consistent-setgid-checks-in-is_sxid.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8d84e39d76bd83474b26cb44f4b338635676e7e8 Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner@xxxxxxxxxx>
Date: Tue, 22 Nov 2022 11:40:32 +0100
Subject: fs: use consistent setgid checks in is_sxid()
From: Christian Brauner <brauner@xxxxxxxxxx>
commit 8d84e39d76bd83474b26cb44f4b338635676e7e8 upstream.
Now that we made the VFS setgid checking consistent an inode can't be
marked security irrelevant even if the setgid bit is still set. Make
this function consistent with all other helpers.
Note that enforcing consistent setgid stripping checks for file
modification and mode- and ownership changes will cause the setgid bit
to be lost in more cases than useed to be the case. If an unprivileged
user wrote to a non-executable setgid file that they don't have
privilege over the setgid bit will be dropped. This will lead to
temporary failures in some xfstests until they have been updated.
Reported-by: Miklos Szeredi <miklos@xxxxxxxxxx>
Signed-off-by: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/fs.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3549,7 +3549,7 @@ int __init list_bdev_fs_names(char *buf,
static inline bool is_sxid(umode_t mode)
{
- return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
+ return mode & (S_ISUID | S_ISGID);
}
static inline int check_sticky(struct user_namespace *mnt_userns,
Patches currently in stable-queue which might be from brauner@xxxxxxxxxx are
queue-6.1/attr-add-setattr_should_drop_sgid.patch
queue-6.1/fs-use-consistent-setgid-checks-in-is_sxid.patch
queue-6.1/attr-add-in_group_or_capable.patch
queue-6.1/fs-move-should_remove_suid.patch
queue-6.1/attr-use-consistent-sgid-stripping-checks.patch
