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 87F83227E95; Tue, 29 Apr 2025 17:40:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745948450; cv=none; b=ELAhL1wXeLt3lmOEKvwXGruPYdDG0KTX+PKYEaDYZJPpFL5ZeUPwHr9fZ8emmA3HZ7MI7qR0xa15gGYCqkevoOVHO2y3eIcEmLOzQVHim5pnVwlc6Any15paCODKZnSoN7S1L9mKqN+BjLAxfrMl4QnK+a+YyBGw64v8svfJDtc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745948450; c=relaxed/simple; bh=H2FPHnH4KV+ld/XhjCM7wnZ7Ni+1cTv6AhFEhn93zjQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=u4xj/9kABDMGY7VW+lzhYrc48rjiWudma+YkcsHWWRKX7vHFQZbNWJmwMRH7Wg4q8Wgt8M+e3Rug/ZsV4OjbXaQ1XLA4ndTN8/w/ffVfqJy7OKjrzoWhsLhsOJhwM26/owJQsA/HYoulLZ8g7rkumjmHkz97mwab+v//RCPVx+U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wEnjVAgw; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wEnjVAgw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 11D51C4CEE3; Tue, 29 Apr 2025 17:40:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745948450; bh=H2FPHnH4KV+ld/XhjCM7wnZ7Ni+1cTv6AhFEhn93zjQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wEnjVAgwGhSBV0LrilrVR84VsdZyQ43kVWr1EMSPznBx4loM0yyPIRzzx81UZMFmw 7go0oH22xBH8ER0RpuqVoWv46lQXxT9X0bzSNQ6yjANQRXy0d93jp+rUQLIRCEexqt X3NQGGSc1aq+gMtXlACigLhr27N/oYHypPa8N5Yw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Trond Myklebust , "Eric W. Biederman" , Christian Brauner , Sasha Levin Subject: [PATCH 5.15 011/373] umount: Allow superblock owners to force umount Date: Tue, 29 Apr 2025 18:38:08 +0200 Message-ID: <20250429161123.598595551@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161123.119104857@linuxfoundation.org> References: <20250429161123.119104857@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Trond Myklebust [ Upstream commit e1ff7aa34dec7e650159fd7ca8ec6af7cc428d9f ] Loosen the permission check on forced umount to allow users holding CAP_SYS_ADMIN privileges in namespaces that are privileged with respect to the userns that originally mounted the filesystem. Signed-off-by: Trond Myklebust Link: https://lore.kernel.org/r/12f212d4ef983714d065a6bb372fbb378753bf4c.1742315194.git.trond.myklebust@hammerspace.com Acked-by: "Eric W. Biederman" Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- fs/namespace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 22af4b6c737f4..642baef4d9aaa 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1734,6 +1734,7 @@ static void warn_mandlock(void) static int can_umount(const struct path *path, int flags) { struct mount *mnt = real_mount(path->mnt); + struct super_block *sb = path->dentry->d_sb; if (!may_mount()) return -EPERM; @@ -1743,7 +1744,7 @@ static int can_umount(const struct path *path, int flags) return -EINVAL; if (mnt->mnt.mnt_flags & MNT_LOCKED) /* Check optimistically */ return -EINVAL; - if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN)) + if (flags & MNT_FORCE && !ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) return -EPERM; return 0; } -- 2.39.5