From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793829654; b=YFxzMmsBIQFDLtwhy+qG5uzz+LvTrX35LYYhXzTmmfqi+GuiL8Z+QWM3mvtRlcqF8TNN uPs/7WQEpKR+lJDjO/kAEpzmhCfrVTdybp0EH+Up8eGmmEM7J6+UM/kFXRqTMyzqLUMgE udIu+OieeU2e0VSKYPKzSmoTtWtxq2K3vJleDV9GMPO/5HNzj2sIOWZmD5z4DnTL3aF8k 4N02/i7m163XAkq6xBRyDFSWv44RpGPJ+c31swZYj3Zqh1DSWhrQtuEUXFP1vzH0v8HWk tHt/RxqRYsct/fRrbFDFx/VISoPpws8RmrBUM0fBtazEvyK2+kMSe/SW76Bm7RwIeUQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793829654; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=qv33A15SdZthJw+nDotKZ5e6RaEkd8QkQB2CgW8WOHE=; b=041FEMqh/dDqkCWZhBfg4oAa0qYcQn1kgLDNFcQyesVGWu+PV7Z+6eUXRPohyTMoIzWn g/N0hpWohjI/oUknNvxybpj/isJReiSaSdk58Z0WPAYfJcH7jci0JacjeOsOmWX4NziGf jevrxVM/cDvontyoUhcLL0xazpmgTU/2YoKFiCGVyI3zJEqMJ4kFFpbYB5qdr0nJnxJDH K0jDKgNV7TIzY/5Nr03HJbIg4hIKWFgveg9qccjWFSvpCx7iAi1682yl3AnQkBKzXL2Lx odYJaf75fY+V+FVikngbbjrzWZglrsvkBpUycO80/yej+feqo/Jgx9xoGhsYDs2EC/g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=r1nxKH0C; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A4953606AC15; Wed, 4 Nov 2026 22:00:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=r1nxKH0C Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42A941F000C1; Wed, 4 Nov 2026 22:00:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793829653; bh=qv33A15SdZthJw+nDotKZ5e6RaEkd8QkQB2CgW8WOHE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=r1nxKH0CymyypHeE7VzUZ4vjirp4QJXhGIO78+DY8abcZ+bd/S4F6Of2shCADAaVc 3kaZbzZBAIu5fJzvfz1G5QxwfGU7j+1oFj0fAkkqBj+FRIkQSOvel2+YApOy/S1iU9 vCgad+oFY8O2SYVhdG6MGgdfhvJSPTnx/wY9HDgU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jay Vadayath , Jan Kara , Sasha Levin Subject: [PATCH 6.18 0257/1005] udf: bound lengthAllocDescs from unallocated space entry Date: Wed, 4 Nov 2026 15:59:50 -0500 Message-ID: <20261104211051.067607455@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jay Vadayath [ Upstream commit b8228f59dc58aea06dc024efd8f64c2d048c4578 ] udf_read_inode() copies the on-disk lengthAllocDescs field of a USE (unallocSpaceEntry) inode into iinfo->i_lenAlloc without checking that it fits in the i_data buffer that is subsequently allocated for the inode. udf_count_free_table(), called from udf_statfs(), then walks the allocation descriptor array up to i_lenAlloc bytes, so a crafted UDF image with lengthAllocDescs larger than (blocksize - sizeof(struct unallocSpaceEntry)) causes udf_get_fileshortad() to read past the end of the kmalloc'd i_data buffer. KASAN report from mounting a crafted UDF image and calling statfs() from an unprivileged process: BUG: KASAN: slab-out-of-bounds in udf_get_fileshortad+0x126/0x130 Read of size 4 at addr ffff8880042137d8 by task poc/65 Call Trace: dump_stack_lvl+0x53/0x70 print_report+0xce/0x610 kasan_report+0xce/0x100 udf_get_fileshortad+0x126/0x130 udf_current_aext+0x3c4/0xa10 udf_next_aext+0x241/0x440 udf_statfs+0xb7d/0x11c0 statfs_by_dentry+0x117/0x1e0 user_statfs+0xac/0x130 __do_sys_statfs+0x80/0xe0 do_syscall_64+0x102/0x5a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reject USE inodes whose lengthAllocDescs would place descriptors past the end of the i_data buffer, mirroring the checks the rest of the UDF code performs on descriptor lengths. This bug was discovered by Artiphishell's vTriage pipeline, which generated a userspace reproducer that reliably triggers the KASAN report on an unpatched kernel. The fix below was drafted with the Claude coding assistant; a userspace reproducer (and the crafted UDF image) is available on request. Assisted-by: LLM Signed-off-by: Jay Vadayath Link: https://patch.msgid.link/20260717184021.13476-1-jay@artiphishell.com Signed-off-by: Jan Kara Signed-off-by: Sasha Levin --- fs/udf/inode.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/udf/inode.c b/fs/udf/inode.c index 84b1a0b7b28d2..e50ecd6746104 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -1488,6 +1488,10 @@ static int udf_read_inode(struct inode *inode, bool hidden_inode) iinfo->i_lenAlloc = le32_to_cpu( ((struct unallocSpaceEntry *)bh->b_data)-> lengthAllocDescs); + if (iinfo->i_lenAlloc > bs - sizeof(struct unallocSpaceEntry)) { + ret = -EFSCORRUPTED; + goto out; + } ret = udf_alloc_i_data(inode, bs - sizeof(struct unallocSpaceEntry)); if (ret) -- 2.53.0