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=1794362249; b=5FbcujVYrcOWdiLw4yg2MMYzo0cJXUbnjisymFF/k+8Unwye2pihbtnt9S0Ozw6wNNvL fBxfKzPCG8aaHcPReTfWOby2eNJLlNftAOYMnn0sQYxCzlQKxE4M+uxJ2giX7RXml18+a 5aRdWFwK8Pc17HgAQIZT/u/rVEQVkqqLIeRcqfTpE2JosB9frqaIh+J6MfE5W35pqwm3c kFeF3GYXPSG6syFS1J91KXjUDgCfF73XAtUU2qcjwqo5E4a0jlxx5CMkT6sTygBa22n1V PKgCWEgybMdEqWlVg3rqZv3gehEfaFXRZH09hS4M/INSPZvCug00a251arLVmVjlUEQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794362249; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=JjNNQnwXb8qSpFmbkOTAc3bWBtRqSwyO7vWdpjQMJbE=; b=AUO1euo908vGF12NEnIXxidznsY50g2XZIe5UCwhM9fNgPXKVqlAgl2xRqxUMTsLz42x w0chvgK5n6JR1kcOF4KoB9agql2J8X543+xlKXrrnUCJb8yJRjHEG3R5s2K6qR040gjbY MAs3HshI3uOgJqE5ZHV7FDc9ThwTpSCQQScCm5K0JFGnKJHLnkMRCWaOcK0h0IyPsFd6J AHQBemTOSaXHyJINgifrcHROI9XmKJjOSjnAlc40Wp2+9mQUzB88s29r/KuinIWW1qwo+ x6J/r1wGYDKAJQ6uKMtzY/H5AWPQoDXLEgHAhPD8wayy8XGG5vQsEVF58Z5lPVeQGAg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=OkPtLOIM; 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 284DB606A31C for ; Wed, 11 Nov 2026 01:57:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=OkPtLOIM Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09E901F0093D; Wed, 11 Nov 2026 01:57:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794362248; bh=JjNNQnwXb8qSpFmbkOTAc3bWBtRqSwyO7vWdpjQMJbE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=OkPtLOIMo+VIjdlQfPwVGmz9FOmcR9Qh2f42dS4Yv44//q0uyGRLgRTEPvRf3RJ2a 1Z6hhBss4RYnIRH64KBg0fZ6Dwe9MdtI+8atGCsTRwkUXweKLUBtzPseCi4f3bfBlu Z1KcAXR11WezN+g/I9wTKWBH6qFnwnBMyDUJKog++VrYDX+pxw0MbyZOqJ8CwoZj4z WC2qoDwmqcKMmprT/ZjnqBTEG3++zoGCy76dL52mx3QxHE4BB/AXqH4eBPXz/prxIY q+UeAa6d5UGfbHhMLJBjiEQQF7krhI8YR7TASPeBx23upWFCMwND8RyK/nyyxaGpJU GnHiWbQke7lSg== From: Sasha Levin To: stable@vger.kernel.org Cc: Aldo Ariel Panzardo , Konstantin Komarov , Sasha Levin Subject: [PATCH 5.15.y 2/3] fs/ntfs3: validate that EA entry size covers its name and value Date: Tue, 10 Nov 2026 20:57:24 -0500 Message-ID: <20261111015355.444686-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261111015355.444686-1-sashal@kernel.org> References: <20261107061313-failed-5.15-351817226fbf@kernel.org> <20261111015355.444686-1-sashal@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Aldo Ariel Panzardo [ Upstream commit 60bd50014cc9a97c5e34a8bddd2bad4d2dc5acb7 ] ntfs_read_ea() walks the on-disk $EA attribute and checks each EA_FULL entry for consistency. For an entry with a non-zero ef->size (the offset to the next entry) the loop only verifies that this stride fits in the remaining buffer, and then continues: if (ef->size) { ea_size = le32_to_cpu(ef->size); if (ea_size > bytes) goto out1; continue; } It never verifies that the entry's own name (ef->name_len) and value (ef->elength) actually fit inside ef->size. A later reader trusts ef->elength unconditionally; ntfs_get_ea() does: len = le16_to_cpu(ea->elength); /* up to 0xffff */ ... if (len > size) /* size is the user buffer */ return -ERANGE; memcpy(buffer, ea->name + ea->name_len + 1, len); A crafted image with a small but valid ef->size (e.g. 24) and ef->elength == 0xffff therefore passes validation, and a getxattr() with a large enough user buffer copies up to 64 KiB starting just past the short entry -- an out-of-bounds read of the ea_all allocation that leaks adjacent kernel heap memory to userspace. BUG: KASAN: slab-out-of-bounds in ntfs_get_ea+0x2b8/0x3f0 Read of size 65535 ... ntfs_get_ea -> ntfs_getxattr -> vfs_getxattr -> do_getxattr The zero-ef->size branch already computes the same struct_size() to derive the stride; mirror that in the non-zero branch and reject the entry when its declared size cannot hold the name and value. Fixes: 0e8235d28f3a ("fs/ntfs3: Check fields while reading") Cc: stable@vger.kernel.org Signed-off-by: Aldo Ariel Panzardo Signed-off-by: Konstantin Komarov Stable-dep-of: 351817226fbf ("fs/ntfs3: validate the EA value length in ntfs_read_ea()") Signed-off-by: Sasha Levin --- fs/ntfs3/xattr.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/fs/ntfs3/xattr.c b/fs/ntfs3/xattr.c index e05fd36cdd89a..ee2f38b912d23 100644 --- a/fs/ntfs3/xattr.c +++ b/fs/ntfs3/xattr.c @@ -166,6 +166,24 @@ static int ntfs_read_ea(struct ntfs_inode *ni, struct EA_FULL **ea, goto out1; if (bytes < offsetof(struct EA_FULL, name)) goto out1; + + /* Check if we can use fields ef->name_len and ef->elength. */ + if (bytes < offsetof(struct EA_FULL, name)) + goto out1; + + /* + * The declared entry size (ef->size) must be large + * enough to hold the name and value. Otherwise a later + * reader such as ntfs_get_ea() copies ef->elength bytes + * starting past the entry, reading out of bounds of the + * ea buffer and leaking adjacent heap memory to + * userspace via getxattr(). + */ + if (struct_size(ef, name, + 1 + ef->name_len + + le16_to_cpu(ef->elength)) > + ea_size) + goto out1; continue; } -- 2.53.0