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 7D82C7F48E for ; Wed, 17 Apr 2024 10:31:15 +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=1713349875; cv=none; b=Ei8trZbb7tTLsj0QbDdbYZBnJoXwfdyKcihufVepJIU/5Dl0ktzHafU1i2U0FC065JwC7JgqyFRhp0xahF/klSUxXuwc/c9b8lIhQBnSKYkJy+Lp+Fdv4Zae7taGBrQZaTPk9w534jxqk3G7G2m1rpbWFZpqi7Yqp1jQmEEtSrk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713349875; c=relaxed/simple; bh=Zx3r2wD3Wo0FDCBKBHg6j9cEkrE6aMJeFRM+XycuAgI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=MaXDeRBFoLds9KSIgGmPxIZOU8QtUd18PEvxN8DtukaGYdzMmC1kdbRyuS5KPxN3kalCXFgTwgJzzaKHe8W6ZaiS+/jvMH6HmLmzlIkJfbAZ0r29A5ujOquSAvM9lx9+anyS5y3PZbRo5jCeTF4ig7g/wgnEzuZOM+/GH3l+4K8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qgIldHzX; 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="qgIldHzX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F417DC072AA; Wed, 17 Apr 2024 10:31:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713349875; bh=Zx3r2wD3Wo0FDCBKBHg6j9cEkrE6aMJeFRM+XycuAgI=; h=From:To:Cc:Subject:Date:Reply-to:From; b=qgIldHzXzr9NupHXQ2ZzBxUzIkHVXLhRJ9ft1mUGx5fhFnOdndLhkLxnYRhMxoJY5 oB9oJaauszqWp0TMmGm9eJfQ2Yom7NlIRRpUIcfnlppxCZ2g6+J3lgKnhejMtqw4+5 mbClWbKyEK+lbyLU0plOmKEpmv3UxfsAqd/Z6lcE= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2024-26906: x86/mm: Disallow vsyscall page read for copy_from_kernel_nofault() Date: Wed, 17 Apr 2024 12:29:21 +0200 Message-ID: <2024041746-CVE-2024-26906-bb35@gregkh> X-Mailer: git-send-email 2.44.0 Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Reply-to: , X-Developer-Signature: v=1; a=openpgp-sha256; l=3753; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=Zx3r2wD3Wo0FDCBKBHg6j9cEkrE6aMJeFRM+XycuAgI=; b=owGbwMvMwCRo6H6F97bub03G02pJDGnyS+Lm21qEV7nIbpUqb9VI5CnRvzPvVoGewN+1T1yit z77VtbfEcvCIMjEICumyPJlG8/R/RWHFL0MbU/DzGFlAhnCwMUpABOpqWRYMOP+yjnPl75XFl+o eDF26uTnKxon72BY0OTj3Hripvuu2SVaF+y6pRu+PLKJBQA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit Description =========== In the Linux kernel, the following vulnerability has been resolved: x86/mm: Disallow vsyscall page read for copy_from_kernel_nofault() When trying to use copy_from_kernel_nofault() to read vsyscall page through a bpf program, the following oops was reported: BUG: unable to handle page fault for address: ffffffffff600000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 3231067 P4D 3231067 PUD 3233067 PMD 3235067 PTE 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 20390 Comm: test_progs ...... 6.7.0+ #58 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...... RIP: 0010:copy_from_kernel_nofault+0x6f/0x110 ...... Call Trace: ? copy_from_kernel_nofault+0x6f/0x110 bpf_probe_read_kernel+0x1d/0x50 bpf_prog_2061065e56845f08_do_probe_read+0x51/0x8d trace_call_bpf+0xc5/0x1c0 perf_call_bpf_enter.isra.0+0x69/0xb0 perf_syscall_enter+0x13e/0x200 syscall_trace_enter+0x188/0x1c0 do_syscall_64+0xb5/0xe0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 ...... ---[ end trace 0000000000000000 ]--- The oops is triggered when: 1) A bpf program uses bpf_probe_read_kernel() to read from the vsyscall page and invokes copy_from_kernel_nofault() which in turn calls __get_user_asm(). 2) Because the vsyscall page address is not readable from kernel space, a page fault exception is triggered accordingly. 3) handle_page_fault() considers the vsyscall page address as a user space address instead of a kernel space address. This results in the fix-up setup by bpf not being applied and a page_fault_oops() is invoked due to SMAP. Considering handle_page_fault() has already considered the vsyscall page address as a userspace address, fix the problem by disallowing vsyscall page read for copy_from_kernel_nofault(). The Linux kernel CVE team has assigned CVE-2024-26906 to this issue. Affected and fixed versions =========================== Fixed in 5.10.214 with commit 6e4694e65b6d Fixed in 5.15.153 with commit e8a67fe34b76 Fixed in 6.1.83 with commit f175de546a3e Fixed in 6.6.23 with commit 57f78c46f081 Fixed in 6.7.11 with commit 29bd6f869046 Fixed in 6.8 with commit 32019c659ecf Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2024-26906 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: arch/x86/mm/maccess.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/6e4694e65b6db4c3de125115dd4f55848cc48381 https://git.kernel.org/stable/c/e8a67fe34b76a49320b33032228a794f40b0316b https://git.kernel.org/stable/c/f175de546a3eb77614d94d4c02550181c0a8493e https://git.kernel.org/stable/c/57f78c46f08198e1be08ffe99c4c1ccc12855bf5 https://git.kernel.org/stable/c/29bd6f86904682adafe9affbc7f79b14defcaff8 https://git.kernel.org/stable/c/32019c659ecfe1d92e3bf9fcdfbb11a7c70acd58