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 114226FA7 for ; Sun, 17 Sep 2023 19:22:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77147C433CC; Sun, 17 Sep 2023 19:22:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694978524; bh=8tLpuBMB/G+U1xiarnc5WkRxQmFOzxC3uIteveDaKXA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TDItgZaWpkeKZtUi8L/XC/LmnklBmbkCXTqwKT0mK1HSUqIvXoJeFWThLKM1D2Km6 8WOrIAoikZtn2Pj6pv+6z7vkrrN6c0BxANy5W/QNlGYlMsArr8hTIbYuyBFb9HiijC T9LoL+RS6UpxtANawTHAtxAPBojrjoUGVk+R4UjA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Christian=20G=C3=B6ttsche?= , Jarkko Sakkinen , Sasha Levin Subject: [PATCH 5.10 047/406] security: keys: perform capable check only on privileged operations Date: Sun, 17 Sep 2023 21:08:21 +0200 Message-ID: <20230917191102.387988861@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230917191101.035638219@linuxfoundation.org> References: <20230917191101.035638219@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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Göttsche [ Upstream commit 2d7f105edbb3b2be5ffa4d833abbf9b6965e9ce7 ] If the current task fails the check for the queried capability via `capable(CAP_SYS_ADMIN)` LSMs like SELinux generate a denial message. Issuing such denial messages unnecessarily can lead to a policy author granting more privileges to a subject than needed to silence them. Reorder CAP_SYS_ADMIN checks after the check whether the operation is actually privileged. Signed-off-by: Christian Göttsche Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: Sasha Levin --- security/keys/keyctl.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 61a614c21b9b6..e3ffaf5ad6394 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -980,14 +980,19 @@ long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group) ret = -EACCES; down_write(&key->sem); - if (!capable(CAP_SYS_ADMIN)) { + { + bool is_privileged_op = false; + /* only the sysadmin can chown a key to some other UID */ if (user != (uid_t) -1 && !uid_eq(key->uid, uid)) - goto error_put; + is_privileged_op = true; /* only the sysadmin can set the key's GID to a group other * than one of those that the current process subscribes to */ if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid)) + is_privileged_op = true; + + if (is_privileged_op && !capable(CAP_SYS_ADMIN)) goto error_put; } @@ -1088,7 +1093,7 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) down_write(&key->sem); /* if we're not the sysadmin, we can only change a key that we own */ - if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) { + if (uid_eq(key->uid, current_fsuid()) || capable(CAP_SYS_ADMIN)) { key->perm = perm; notify_key(key, NOTIFY_KEY_SETATTR, 0); ret = 0; -- 2.40.1