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 9E362129A80 for ; Tue, 20 Feb 2024 18:34:27 +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=1708454067; cv=none; b=EZTE8dNiaq1mKf9eYHPSL67etT30NjiMbHOe4qRZ6SGFKFcUfMxP9mrAxtFin7A56q0aDErNz+BxmBunJKI5x61lBvQTRt+WoWzQKmuOeb+Ys7QhkS8o/nKAdexQucN+FJlBS60apLS/uDdIZlZbr2WnPtGSPXULrIF+SBoj9sw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708454067; c=relaxed/simple; bh=kkYWDOaAPUUXIq66iFCkLMgFEVmioB8nGCR3zv+3FvM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Ku+W4CuoUi4hLcTodLVC4v/gmQAJ6HTLlKSQIfyvj7Jee2hlPoBamXytrO6m5C0KNjgbgLOumBedPCeZvR9n4VlVrj92ZxZN1DeSoPgHZ+9lnROtgX8RYAcJ2C0h0H7R4N82QbzF2O+IM67qZHXCJ4xYwg7nOsV5aWurHTyiTww= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=D3YKO6MW; 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="D3YKO6MW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB050C433F1; Tue, 20 Feb 2024 18:34:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708454067; bh=kkYWDOaAPUUXIq66iFCkLMgFEVmioB8nGCR3zv+3FvM=; h=From:To:Cc:Subject:Date:Reply-to:From; b=D3YKO6MWL2AV/hY3Wr122RXuMZTzM2BSNJ/Z2W+ZH5EVmM7gIgV6nYyjnUSfF3hy6 b9j2HVvv+4QAxV/q1jY+X5eCYTEjpihE93KbuqEcfvpOggH416Ld1nUAFVbwC1jLsS vZxsYWXnaWpoCsAEReMp7Kd2c3sPWsCmf/UtgUEo= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2023-52438: binder: fix use-after-free in shinker's callback Date: Tue, 20 Feb 2024 19:34:17 +0100 Message-ID: <2024022017-slit-wish-e5d7@gregkh> X-Mailer: git-send-email 2.43.2 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=4691; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=kkYWDOaAPUUXIq66iFCkLMgFEVmioB8nGCR3zv+3FvM=; b=owGbwMvMwCRo6H6F97bub03G02pJDKlXPqyclCwwj/t2S07m1WPd0ou63278Nm/H2a1MxwvOG RwXfPU4vCOWhUGQiUFWTJHlyzaeo/srDil6GdqehpnDygQyhIGLUwAmsmcDw/yoW3H7ik7euunS bdWX3eFUmyNsdJRhwf4+seo+hQs3ShQnL6y+17KBY71uEAA= 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: binder: fix use-after-free in shinker's callback The mmap read lock is used during the shrinker's callback, which means that using alloc->vma pointer isn't safe as it can race with munmap(). As of commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") the mmap lock is downgraded after the vma has been isolated. I was able to reproduce this issue by manually adding some delays and triggering page reclaiming through the shrinker's debug sysfs. The following KASAN report confirms the UAF: ================================================================== BUG: KASAN: slab-use-after-free in zap_page_range_single+0x470/0x4b8 Read of size 8 at addr ffff356ed50e50f0 by task bash/478 CPU: 1 PID: 478 Comm: bash Not tainted 6.6.0-rc5-00055-g1c8b86a3799f-dirty #70 Hardware name: linux,dummy-virt (DT) Call trace: zap_page_range_single+0x470/0x4b8 binder_alloc_free_page+0x608/0xadc __list_lru_walk_one+0x130/0x3b0 list_lru_walk_node+0xc4/0x22c binder_shrink_scan+0x108/0x1dc shrinker_debugfs_scan_write+0x2b4/0x500 full_proxy_write+0xd4/0x140 vfs_write+0x1ac/0x758 ksys_write+0xf0/0x1dc __arm64_sys_write+0x6c/0x9c Allocated by task 492: kmem_cache_alloc+0x130/0x368 vm_area_alloc+0x2c/0x190 mmap_region+0x258/0x18bc do_mmap+0x694/0xa60 vm_mmap_pgoff+0x170/0x29c ksys_mmap_pgoff+0x290/0x3a0 __arm64_sys_mmap+0xcc/0x144 Freed by task 491: kmem_cache_free+0x17c/0x3c8 vm_area_free_rcu_cb+0x74/0x98 rcu_core+0xa38/0x26d4 rcu_core_si+0x10/0x1c __do_softirq+0x2fc/0xd24 Last potentially related work creation: __call_rcu_common.constprop.0+0x6c/0xba0 call_rcu+0x10/0x1c vm_area_free+0x18/0x24 remove_vma+0xe4/0x118 do_vmi_align_munmap.isra.0+0x718/0xb5c do_vmi_munmap+0xdc/0x1fc __vm_munmap+0x10c/0x278 __arm64_sys_munmap+0x58/0x7c Fix this issue by performing instead a vma_lookup() which will fail to find the vma that was isolated before the mmap lock downgrade. Note that this option has better performance than upgrading to a mmap write lock which would increase contention. Plus, mmap_write_trylock() has been recently removed anyway. The Linux kernel CVE team has assigned CVE-2023-52438 to this issue. Affected and fixed versions =========================== Issue introduced in 4.20 with commit dd2283f2605e and fixed in 5.4.268 with commit a53e15e592b4 Issue introduced in 4.20 with commit dd2283f2605e and fixed in 5.10.209 with commit c8c1158ffb00 Issue introduced in 4.20 with commit dd2283f2605e and fixed in 5.15.148 with commit 8ad4d580e8af Issue introduced in 4.20 with commit dd2283f2605e and fixed in 6.1.74 with commit 9fa04c93f241 Issue introduced in 4.20 with commit dd2283f2605e and fixed in 6.6.13 with commit a49087ab9350 Issue introduced in 4.20 with commit dd2283f2605e and fixed in 6.7.1 with commit e074686e993f Issue introduced in 4.20 with commit dd2283f2605e and fixed in 6.8-rc1 with commit 3f489c2067c5 Please see https://www.kernel.org or 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-2023-52438 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_alloc.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/a53e15e592b4dcc91c3a3b8514e484a0bdbc53a3 https://git.kernel.org/stable/c/c8c1158ffb007197f31f9d9170cf13e4f34cbb5c https://git.kernel.org/stable/c/8ad4d580e8aff8de2a4d57c5930fcc29f1ffd4a6 https://git.kernel.org/stable/c/9fa04c93f24138747807fe75b5591bb680098f56 https://git.kernel.org/stable/c/a49087ab93508b60d9b8add91707a22dda832869 https://git.kernel.org/stable/c/e074686e993ff1be5f21b085a3b1b4275ccd5727 https://git.kernel.org/stable/c/3f489c2067c5824528212b0fc18b28d51332d906