From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF376611A for ; Mon, 28 Aug 2023 10:33:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 30176C433C8; Mon, 28 Aug 2023 10:33:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1693218833; bh=KxvcsIN2Q8nGQ1rDystgEo3sbuVZ4r69ffXhLfhwnTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mEIrcfWvJWdRxLkzQ+GaAspaTNOpOLDaFj6w9kEeUE7t6axdpGioBH8oLJhK2QTH9 A2fhblUwTqEkPZie3c/34aoRcbBfZEfeaYvOW+U8n15RUpk50bZz7ZsvMljbsceSfM eAZrXVHI+d0NstZ+9MzYOT4N0EpHbCn4jdIBedPg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sherry Yang , Christian Brauner , Jeff Layton , Chuck Lever , Harshit Mogalapalli Subject: [PATCH 6.1 100/122] nfsd: use vfs setgid helper Date: Mon, 28 Aug 2023 12:13:35 +0200 Message-ID: <20230828101159.733955856@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230828101156.480754469@linuxfoundation.org> References: <20230828101156.480754469@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Brauner commit 2d8ae8c417db284f598dffb178cc01e7db0f1821 upstream. We've aligned setgid behavior over multiple kernel releases. The details can be found in commit cf619f891971 ("Merge tag 'fs.ovl.setgid.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping") and commit 426b4ca2d6a5 ("Merge tag 'fs.setgid.v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux"). Consistent setgid stripping behavior is now encapsulated in the setattr_should_drop_sgid() helper which is used by all filesystems that strip setgid bits outside of vfs proper. Usually ATTR_KILL_SGID is raised in e.g., chown_common() and is subject to the setattr_should_drop_sgid() check to determine whether the setgid bit can be retained. Since nfsd is raising ATTR_KILL_SGID unconditionally it will cause notify_change() to strip it even if the caller had the necessary privileges to retain it. Ensure that nfsd only raises ATR_KILL_SGID if the caller lacks the necessary privileges to retain the setgid bit. Without this patch the setgid stripping tests in LTP will fail: > As you can see, the problem is S_ISGID (0002000) was dropped on a > non-group-executable file while chown was invoked by super-user, while [...] > fchown02.c:66: TFAIL: testfile2: wrong mode permissions 0100700, expected 0102700 [...] > chown02.c:57: TFAIL: testfile2: wrong mode permissions 0100700, expected 0102700 With this patch all tests pass. Reported-by: Sherry Yang Signed-off-by: Christian Brauner Reviewed-by: Jeff Layton Cc: Signed-off-by: Chuck Lever [Harshit: backport to 6.1.y: Use init_user_ns instead of nop_mnt_idmap as we don't have commit abf08576afe3 ("fs: port vfs_*() helpers to struct mnt_idmap")] Signed-off-by: Harshit Mogalapalli Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/vfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -321,7 +321,9 @@ nfsd_sanitize_attrs(struct inode *inode, iap->ia_mode &= ~S_ISGID; } else { /* set ATTR_KILL_* bits and let VFS handle it */ - iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID); + iap->ia_valid |= ATTR_KILL_SUID; + iap->ia_valid |= + setattr_should_drop_sgid(&init_user_ns, inode); } } }