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 6BEC73EF0A5 for ; Fri, 8 May 2026 14:25:28 +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=1778250328; cv=none; b=SF++MVjSvrQw/kX7lBCce5kAxPca9asCCbjGHjrJjqfXhuyyAgnKtGKCL9NG6v/BHuiIPmYnd08Z51sDP/NPoKp0zAmCAodW9XvKrlOQ4uze4+uF2LnFSjy0bJKgWDq4/k3+rDiY8sLstXiVVfg4OpXWJv1KM1CbX5grobhdok4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778250328; c=relaxed/simple; bh=i9rHqdnZTuGgR73azL5AY4QPa47in3ydXw4qJ+Ee9LI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=bQxIdHrTE6n6tTtG2CMdMVzg7Ol4C34AhOAWl0JUb/BIh4wdpO7iapR5D01We4Dba9Ub4Fp39HQ7bsJM+Waj7daGHX+T1llfwQ5ff3sw0fggiVEgvUzKxKQpDRMLOXHlJfgejKOLdp1DHZmUFjbT4UGXSsFJz2vL1JMqQ+0L9Hs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=z8frft16; 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="z8frft16" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED1BCC2BCC7; Fri, 8 May 2026 14:25:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778250328; bh=i9rHqdnZTuGgR73azL5AY4QPa47in3ydXw4qJ+Ee9LI=; h=From:To:Cc:Subject:Date:Reply-To:From; b=z8frft16CIt6haGIGl/tH7do1yEVfUrHoeElw3jfLYpe9J8DDjqVF9acthLAM5/B+ dLSANM5hz3EtLbSGy9WA0j1ccEzR12jeq5/vkiU6Qu6zP5x+TVyi0bHMQOloxLuPDC Ej7M3Hw2NKvWYcK5B41Vff1fa6t3kab1h8bhtbF0= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-43434: rust_binder: check ownership before using vma Date: Fri, 8 May 2026 16:22:43 +0200 Message-ID: <2026050851-CVE-2026-43434-c5a6@gregkh> X-Mailer: git-send-email 2.54.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3671; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=tmaLhS+7/nsIr58HJ2qw+IsHWDCT2HwrLFqFIYlOb3U=; b=owGbwMvMwCRo6H6F97bub03G02pJDJl/PzasfdQwhW/Lh864ynuRn7PVI9bFuD421dAJqlnv0 KbO38PQEcvCIMjEICumyPJlG8/R/RWHFL0MbU/DzGFlAhnCwMUpABOJkGSYZ2MRNje4qqBU4Nib C+c2Hjf35Dxhz7CgpSBQNChNSuvjnEdrlG/8qks63uYIAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: rust_binder: check ownership before using vma When installing missing pages (or zapping them), Rust Binder will look up the vma in the mm by address, and then call vm_insert_page (or zap_page_range_single). However, if the vma is closed and replaced with a different vma at the same address, this can lead to Rust Binder installing pages into the wrong vma. By installing the page into a writable vma, it becomes possible to write to your own binder pages, which are normally read-only. Although you're not supposed to be able to write to those pages, the intent behind the design of Rust Binder is that even if you get that ability, it should not lead to anything bad. Unfortunately, due to another bug, that is not the case. To fix this, store a pointer in vm_private_data and check that the vma returned by vma_lookup() has the right vm_ops and vm_private_data before trying to use the vma. This should ensure that Rust Binder will refuse to interact with any other VMA. The plan is to introduce more vma abstractions to avoid this unsafe access to vm_ops and vm_private_data, but for now let's start with the simplest possible fix. C Binder performs the same check in a slightly different way: it provides a vm_ops->close that sets a boolean to true, then checks that boolean after calling vma_lookup(), but this is more fragile than the solution in this patch. (We probably still want to do both, but the vm_ops->close callback will be added later as part of the follow-up vma API changes.) It's still possible to remap the vma so that pages appear in the right vma, but at the wrong offset, but this is a separate issue and will be fixed when Rust Binder gets a vm_ops->close callback. The Linux kernel CVE team has assigned CVE-2026-43434 to this issue. Affected and fixed versions =========================== Issue introduced in 6.18 with commit eafedbc7c050c44744fbdf80bdf3315e860b7513 and fixed in 6.18.19 with commit 20a01f20d1f4064d90a8627aa41b5987f0220bb9 Issue introduced in 6.18 with commit eafedbc7c050c44744fbdf80bdf3315e860b7513 and fixed in 6.19.9 with commit 5a472d04fb4b9115fb7d1535bd885cea450f14db Issue introduced in 6.18 with commit eafedbc7c050c44744fbdf80bdf3315e860b7513 and fixed in 7.0 with commit 8ef2c15aeae07647f530d30f6daaf79eb801bcd1 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-2026-43434 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: drivers/android/binder/page_range.rs 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/20a01f20d1f4064d90a8627aa41b5987f0220bb9 https://git.kernel.org/stable/c/5a472d04fb4b9115fb7d1535bd885cea450f14db https://git.kernel.org/stable/c/8ef2c15aeae07647f530d30f6daaf79eb801bcd1