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 9B4653EF66A for ; Fri, 8 May 2026 14:24:24 +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=1778250264; cv=none; b=EJwtTVI22am/kasynoFgHKq2FCGCpGjL94mwnfb8Ktr5DycUBaK7D4cp5+3oefQsBxBtiNK0P+E0p5Nu5zXlbada+hHhrkOKl6xnI15ooIPRuiyki1LAFQU2pq6qj6Jbn9t8s0Rtl8d/4ZNlI5SZsMBw9n3LOJQKVYALt6Yzp74= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778250264; c=relaxed/simple; bh=XFW+xOSK8QMiuBmhJdK4s9nu2QkgGKqo8AYfJxtLPz0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=uyUedMr185IjwGFeMNmw2xUe+yiF76oG7Wa5SwGo1a2Rc8O18YiBpOp21GQTvLp/0/JOkTuI2bnaxrqEtj3TZXqq+z5RmppqehEliD0xMvNockfVAkQ7FGCgUxpJm7Cxwfit19i71cykXD/8lpxV6QZrX51lDprUQaYsKZwfRY4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yQEg+gFt; 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="yQEg+gFt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37A03C2BCB0; Fri, 8 May 2026 14:24:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778250264; bh=XFW+xOSK8QMiuBmhJdK4s9nu2QkgGKqo8AYfJxtLPz0=; h=From:To:Cc:Subject:Date:Reply-To:From; b=yQEg+gFtRmCNw0S5ACvLfHQSmBFLenGJe+zyrBRmmWkgpZpGen+uJwJriY7G5OLGP 6fC71oOIqmecWNEeSlaZ3LGA+hgRpu2KuNg+gdHMP5UWA8lupL0M3qHW/QaA/7JFP2 ruUWEZ9DZwyKmoF/iT9Wpb5Lm6ct5sIA1t+GPgmQ= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-43408: ceph: add a bunch of missing ceph_path_info initializers Date: Fri, 8 May 2026 16:22:17 +0200 Message-ID: <2026050842-CVE-2026-43408-6f0a@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=3968; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=sqN5eEINSW8zjARgip7/By5/cFpO7YPle1rr/iHReac=; b=owGbwMvMwCRo6H6F97bub03G02pJDJl/P5axJ/U0Bp1aEBu81TOS9Qr3Nccze0yaT2Y1LHl3o vWn4NXejlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZjIenGGBRfaQr5eWLT88q67 36syvmgqfT145RPDfNfO9mrbg+1ybXY9S2t+sz5edPD2KgA= 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: ceph: add a bunch of missing ceph_path_info initializers ceph_mdsc_build_path() must be called with a zero-initialized ceph_path_info parameter, or else the following ceph_mdsc_free_path_info() may crash. Example crash (on Linux 6.18.12): virt_to_cache: Object is not a Slab page! WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6732 kmem_cache_free+0x316/0x400 [...] Call Trace: [...] ceph_open+0x13d/0x3e0 do_dentry_open+0x134/0x480 vfs_open+0x2a/0xe0 path_openat+0x9a3/0x1160 [...] cache_from_obj: Wrong slab cache. names_cache but object is from ceph_inode_info WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6746 kmem_cache_free+0x2dd/0x400 [...] kernel BUG at mm/slub.c:634! Oops: invalid opcode: 0000 [#1] SMP NOPTI RIP: 0010:__slab_free+0x1a4/0x350 Some of the ceph_mdsc_build_path() callers had initializers, but others had not, even though they were all added by commit 15f519e9f883 ("ceph: fix race condition validating r_parent before applying state"). The ones without initializer are suspectible to random crashes. (I can imagine it could even be possible to exploit this bug to elevate privileges.) Unfortunately, these Ceph functions are undocumented and its semantics can only be derived from the code. I see that ceph_mdsc_build_path() initializes the structure only on success, but not on error. Calling ceph_mdsc_free_path_info() after a failed ceph_mdsc_build_path() call does not even make sense, but that's what all callers do, and for it to be safe, the structure must be zero-initialized. The least intrusive approach to fix this is therefore to add initializers everywhere. The Linux kernel CVE team has assigned CVE-2026-43408 to this issue. Affected and fixed versions =========================== Issue introduced in 6.12.48 with commit db378e6f83ec705c6091c65d482d555edc2b0a72 and fixed in 6.12.78 with commit 644b47f0574fd82aeb9d00317eca8d1f2a525c8c Issue introduced in 6.17 with commit 15f519e9f883b316d86e2bb6b767a023aafd9d83 and fixed in 6.18.19 with commit 8be8911f590813e6f90bc6407ced1b23e50bc5da Issue introduced in 6.17 with commit 15f519e9f883b316d86e2bb6b767a023aafd9d83 and fixed in 6.19.9 with commit 453df1f4535842bf17ff1885a225e153d7ee3374 Issue introduced in 6.17 with commit 15f519e9f883b316d86e2bb6b767a023aafd9d83 and fixed in 7.0 with commit 43323a5934b660afae687e8e4e95ac328615a5c4 Issue introduced in 6.16.8 with commit 2bfe45987eb346e299d9f763f9cd05f77011519f 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-2026-43408 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: fs/ceph/debugfs.c fs/ceph/dir.c fs/ceph/file.c fs/ceph/inode.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/644b47f0574fd82aeb9d00317eca8d1f2a525c8c https://git.kernel.org/stable/c/8be8911f590813e6f90bc6407ced1b23e50bc5da https://git.kernel.org/stable/c/453df1f4535842bf17ff1885a225e153d7ee3374 https://git.kernel.org/stable/c/43323a5934b660afae687e8e4e95ac328615a5c4