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 543B81292F3; Tue, 23 Jan 2024 00:11:48 +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=1705968708; cv=none; b=fRaffHVnw6UISvIzcraRtatT7glNXUsXsHWCwoGyCE4p4CMTdx5Xe4jXDtT6hX2ZRE85Zatgm6TED2jDkVypk/MJ88ig7G8q10IuUU6l3euCTUBdhQttZ3EM+dSb/AWGNXLdP8HQWwi2hsbRU+YukqP9cTwy+s7DilK4ghOzKKM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705968708; c=relaxed/simple; bh=/msEkxcnJSjp1fTSBzuJbXU9Xvchs6YpVm2y3YGaH9M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cc6VNP0Xc96xeHtqIIYdrX4OHSbY8T8vOoPx7d9+UPep3NiJgjn0RKutGiG38pO3AU3mz9aodlMe+tHxj20lG6gIknesNEqH4Y9133UcnJaX7UUbZniREXRdC7+C1rcWjCqsElQGIvoqau1KM4DoYkN98Sk3CVuUSpiMQFC/ha4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UxwclgCt; 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="UxwclgCt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA65DC433C7; Tue, 23 Jan 2024 00:11:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705968708; bh=/msEkxcnJSjp1fTSBzuJbXU9Xvchs6YpVm2y3YGaH9M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UxwclgCtG0J7HOqwIzvU3sYZqZBevPzHzSyH7GKyCYmHCTPBB9UGzDuOoqxckIr6O FK/KWomypctlMyVQQDawTrdr6KQLCVSpO7FMkDQfkqVWtnJNfS+jt08rZE59cohowh hIk7Ih+xZNeoq7enk9/Z/bJdQdIgwm7njPK9Qv/Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fedor Pchelkin , John Johansen , Sasha Levin Subject: [PATCH 4.19 137/148] apparmor: avoid crash when parsed profile name is empty Date: Mon, 22 Jan 2024 15:58:13 -0800 Message-ID: <20240122235718.108986851@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235712.442097787@linuxfoundation.org> References: <20240122235712.442097787@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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Fedor Pchelkin [ Upstream commit 55a8210c9e7d21ff2644809699765796d4bfb200 ] When processing a packed profile in unpack_profile() described like "profile :ns::samba-dcerpcd /usr/lib*/samba/{,samba/}samba-dcerpcd {...}" a string ":samba-dcerpcd" is unpacked as a fully-qualified name and then passed to aa_splitn_fqname(). aa_splitn_fqname() treats ":samba-dcerpcd" as only containing a namespace. Thus it returns NULL for tmpname, meanwhile tmpns is non-NULL. Later aa_alloc_profile() crashes as the new profile name is NULL now. general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 6 PID: 1657 Comm: apparmor_parser Not tainted 6.7.0-rc2-dirty #16 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:strlen+0x1e/0xa0 Call Trace: ? strlen+0x1e/0xa0 aa_policy_init+0x1bb/0x230 aa_alloc_profile+0xb1/0x480 unpack_profile+0x3bc/0x4960 aa_unpack+0x309/0x15e0 aa_replace_profiles+0x213/0x33c0 policy_update+0x261/0x370 profile_replace+0x20e/0x2a0 vfs_write+0x2af/0xe00 ksys_write+0x126/0x250 do_syscall_64+0x46/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 ---[ end trace 0000000000000000 ]--- RIP: 0010:strlen+0x1e/0xa0 It seems such behaviour of aa_splitn_fqname() is expected and checked in other places where it is called (e.g. aa_remove_profiles). Well, there is an explicit comment "a ns name without a following profile is allowed" inside. AFAICS, nothing can prevent unpacked "name" to be in form like ":samba-dcerpcd" - it is passed from userspace. Deny the whole profile set replacement in such case and inform user with EPROTO and an explaining message. Found by Linux Verification Center (linuxtesting.org). Fixes: 04dc715e24d0 ("apparmor: audit policy ns specified in policy load") Signed-off-by: Fedor Pchelkin Signed-off-by: John Johansen Signed-off-by: Sasha Levin --- security/apparmor/policy_unpack.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c index 41da5ccc3f3e..683f551ec33b 100644 --- a/security/apparmor/policy_unpack.c +++ b/security/apparmor/policy_unpack.c @@ -635,6 +635,10 @@ static struct aa_profile *unpack_profile(struct aa_ext *e, char **ns_name) tmpname = aa_splitn_fqname(name, strlen(name), &tmpns, &ns_len); if (tmpns) { + if (!tmpname) { + info = "empty profile name"; + goto fail; + } *ns_name = kstrndup(tmpns, ns_len, GFP_KERNEL); if (!*ns_name) { info = "out of memory"; -- 2.43.0