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 A273C1F9A92 for ; Mon, 21 Oct 2024 18:09:16 +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=1729534156; cv=none; b=cRgCWXGXX8AM4nOwLm+NnBNAy6W4W997QbyGAgi+2pnEdsVwvJt5T/N/2U/QQd6p9mcmUVnwH0jcUP8599QzLf3YxPQqWCSVl9FSjSZ/tJ6wkLPwm2DCIPLRk/joo1YAkLg6PMyWoaRphobRHr1FuYcT87r8BYffQd7uJi+Mfh4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729534156; c=relaxed/simple; bh=CfqWk7Evui10mVNOEP1bU3Szk7eLRwbC5b1AMKw160g=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=bVnYNUjhtxgDwg6N8Uis2cVQGUg55K8jTlyPkBVRLSLvfHUp1HVWjbLS2q9b/EefgRgxTE/u16Kw/isZmXVnYfG8r1ADMCpymc9KHvqdUNu2bilVYHo2a2QN5NKkFOVvHoqXKWBR/aaAPxeTpdbqjIRQl8OzPU/GKpQxrL9gpX4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=G2ypB0ej; 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="G2ypB0ej" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 22D3EC4CEC3; Mon, 21 Oct 2024 18:09:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1729534156; bh=CfqWk7Evui10mVNOEP1bU3Szk7eLRwbC5b1AMKw160g=; h=From:To:Cc:Subject:Date:Reply-to:From; b=G2ypB0ej6Wi02bUBB9ClLJctvdshTnZDs0r/+Z7FGd8FFuSLwy3entgy9cX6lYSXo QADZBLPCwk6vUfIBQevRPgsrDAl0TbHUtzxR4+ddlziCKTW8HLBm0bpPSzK3BWN2TD onIokF4/P30yiG6rQJyHc2wp3Ke4Es6wYBh8zenI= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2024-50002: static_call: Handle module init failure correctly in static_call_del_module() Date: Mon, 21 Oct 2024 20:03:30 +0200 Message-ID: <2024102139-CVE-2024-50002-bdfd@gregkh> X-Mailer: git-send-email 2.47.0 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=4918; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=CfqWk7Evui10mVNOEP1bU3Szk7eLRwbC5b1AMKw160g=; b=owGbwMvMwCRo6H6F97bub03G02pJDOli05njMrzK/p71mr5tRbxOSDm/h1jA88glKxtmLHqud nTOooMpHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjARiRkMC7YqeTBtkXQ9lHN8 +vpX7uyptYoaIQwLJrGv+7ntyTltuf13N2gWWWlvXdvlAwA= 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: static_call: Handle module init failure correctly in static_call_del_module() Module insertion invokes static_call_add_module() to initialize the static calls in a module. static_call_add_module() invokes __static_call_init(), which allocates a struct static_call_mod to either encapsulate the built-in static call sites of the associated key into it so further modules can be added or to append the module to the module chain. If that allocation fails the function returns with an error code and the module core invokes static_call_del_module() to clean up eventually added static_call_mod entries. This works correctly, when all keys used by the module were converted over to a module chain before the failure. If not then static_call_del_module() causes a #GP as it blindly assumes that key::mods points to a valid struct static_call_mod. The problem is that key::mods is not a individual struct member of struct static_call_key, it's part of a union to save space: union { /* bit 0: 0 = mods, 1 = sites */ unsigned long type; struct static_call_mod *mods; struct static_call_site *sites; }; key::sites is a pointer to the list of built-in usage sites of the static call. The type of the pointer is differentiated by bit 0. A mods pointer has the bit clear, the sites pointer has the bit set. As static_call_del_module() blidly assumes that the pointer is a valid static_call_mod type, it fails to check for this failure case and dereferences the pointer to the list of built-in call sites, which is obviously bogus. Cure it by checking whether the key has a sites or a mods pointer. If it's a sites pointer then the key is not to be touched. As the sites are walked in the same order as in __static_call_init() the site walk can be terminated because all subsequent sites have not been touched by the init code due to the error exit. If it was converted before the allocation fail, then the inner loop which searches for a module match will find nothing. A fail in the second allocation in __static_call_init() is harmless and does not require special treatment. The first allocation succeeded and converted the key to a module chain. That first entry has mod::mod == NULL and mod::next == NULL, so the inner loop of static_call_del_module() will neither find a module match nor a module chain. The next site in the walk was either already converted, but can't match the module, or it will exit the outer loop because it has a static_call_site pointer and not a static_call_mod pointer. The Linux kernel CVE team has assigned CVE-2024-50002 to this issue. Affected and fixed versions =========================== Issue introduced in 5.10 with commit 9183c3f9ed71 and fixed in 5.15.168 with commit ed4c8ce0f307 Issue introduced in 5.10 with commit 9183c3f9ed71 and fixed in 6.1.113 with commit b566c7d8a2de Issue introduced in 5.10 with commit 9183c3f9ed71 and fixed in 6.6.55 with commit c0abbbe8c98c Issue introduced in 5.10 with commit 9183c3f9ed71 and fixed in 6.10.14 with commit 2b494471797b Issue introduced in 5.10 with commit 9183c3f9ed71 and fixed in 6.11.3 with commit 9c48c2b53191 Issue introduced in 5.10 with commit 9183c3f9ed71 and fixed in 6.12-rc1 with commit 4b30051c4864 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-2024-50002 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: kernel/static_call_inline.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/ed4c8ce0f307f2ab8778aeb40a8866d171e8f128 https://git.kernel.org/stable/c/b566c7d8a2de403ccc9d8a06195e19bbb386d0e4 https://git.kernel.org/stable/c/c0abbbe8c98c077292221ec7e2baa667c9f0974c https://git.kernel.org/stable/c/2b494471797bff3d257e99dc0a7abb0c5ff3b4cd https://git.kernel.org/stable/c/9c48c2b53191bf991361998f5bb97b8f2fc5a89c https://git.kernel.org/stable/c/4b30051c4864234ec57290c3d142db7c88f10d8a