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 ED6C6214812; Mon, 31 Mar 2025 14:32:18 +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=1743431540; cv=none; b=rjefzdtmi1tSanoz9xYvHvhjuIHrKPmiFFUlLxNlg5tZOtu6wh+obFsmmCaBg9igO2gmCnxBxbVJ43UsCJnr95iwSdRjeURFmg25X2ZV89gnugOTHKjfeENwuvaFosrKl3+JjwYhuUqxW5f/KyOsuuWAms1tb4VYU5HoYSQiSiE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743431540; c=relaxed/simple; bh=zOM8DZdAAwTvYRuEl5bCkuiPICOlbnZjGvAKYVEvcMY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=X5RWVoB2AKD1KZiCq7Jbb6qA958bhwSV4Lh/8gSnStmU8FOXWxmHLgFnfSpc6NXo9O8JLn8CoRZoXYtQpCYQVrRPbaPpXyg1nJmPeqkMNbAlpt76v7QgNuIuNXN7doK8yJEgAzyJTNi6ujpoW0AF/TzqNmACi69fwZ5NNhsYwVM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UiucjysO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UiucjysO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85BF0C4CEE9; Mon, 31 Mar 2025 14:32:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743431538; bh=zOM8DZdAAwTvYRuEl5bCkuiPICOlbnZjGvAKYVEvcMY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UiucjysOO3yIER+ZMQpyf48ZT7yAHcOvfPgGizFUk7bTJlROfdcjd/BbnzzQDKJEL PcWPnPqNlLFFSCCEGdSywoUs8gybu7yaaOUWk8SGM+tx3inXXnjLRgqdSbL44L5YRi gVLh6DeQb3/Zjw1c0mRgCMkuXrC9X6yBoqlBlwgsoA1W1wgMQvtSKPlDcbt+8aq77H I2Ykk4hyyXTCcv+jLGr5cYTjJKgtKyx/h0XHRSFemb8XhbEpzx7zmAUCBBb02dU6YF 1vi4SDgodRyQTNdfU3RMmTib0ooeL9VZn2E06+eL2df7ye8TZgsGfB2cEY/9I8vvIS U2ysEusFZ7ekw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Trond Myklebust , "Eric W. Biederman" , Christian Brauner , Sasha Levin , viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 6.13 2/2] umount: Allow superblock owners to force umount Date: Mon, 31 Mar 2025 10:32:14 -0400 Message-Id: <20250331143214.1667735-2-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250331143214.1667735-1-sashal@kernel.org> References: <20250331143214.1667735-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.13.9 Content-Transfer-Encoding: 8bit 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 cb08db40fc039..6a22882d5f54c 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1986,6 +1986,7 @@ 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; @@ -1995,7 +1996,7 @@ 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