From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 713113822B7; Sat, 17 Oct 2026 16:31:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254701; cv=none; b=AD7uVNcuxjO7STHp/0GKYmb4sAmZjiMBR+PQDO7u5+a+4uyS2bwB7K+lwCxRbkQKhy0J2qLVU6iHBeS7Gdo8BMfNu8i8GV4FN7tFI84Wtk0d+z+LFTZk7yON9xwiFZMCf66d7Z56qcOiQcXHj1Gq6758iQb+gAdJ0dzTnCQbuEc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254701; c=relaxed/simple; bh=KeK3cT4kSB+XZiwsOogx1et2L6P8EJJGx5F2nAQe/vM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=u4EOdcxjq9mbqXb54GpeoLJ9cAtY/Oc5unHq58T8Oe04nirBZn7pBWgRtJWXNE5nZBKo4R0bbHvWUnposPVJ9oE+UZOMNYf1RqBYFCcS8PLL1zu+KAvTpRoJW3tUnh44Yj+NQ1EZ4nLH4El1hG6RQo86IWkGo+JB/2puhc9vWfY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tmyXhgHi; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tmyXhgHi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C676F1F000C4; Sat, 17 Oct 2026 16:31:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792254700; bh=vxalMwLRbNnz8NcIpPOu6sSinBAMo6BCe/ktEt0at/Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=tmyXhgHiv3F5JQtdFRsQu7Xx9RXIORhdyIv618Ta9QiiXZ1cjmtBNd4eEbaGXKWi3 aeTWzyYaG7ee+qqMU0HycOkL+rEFB/FJUi9DGTNCcISNPdgKJcZqoov8ihEUvAl7HP 21/hHn/iD+NoXPBG3B3xMQmbBW6wUYhRu062LRCw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiang Mei , Qu Wenruo , Weiming Shi , David Sterba , Sasha Levin Subject: [PATCH 6.12 533/869] btrfs: lzo: reject compressed segment that overflows the compressed input Date: Sat, 17 Oct 2026 17:56:14 +0200 Message-ID: <20261017160050.769362913@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Weiming Shi [ Upstream commit b0d27d43791b7a3057c3c4aedf9b4aa033d37c46 ] lzo_decompress_bio() validates each on-disk segment length seg_len only against the workspace cbuf size, not against the compressed input size (compressed_len, the total folio bytes of the bio). A crafted extent can carry a segment whose seg_len passes the cbuf check but runs past the end of the bio, so copy_compressed_segment() walks off the last folio: get_current_folio() then returns the NULL folio from bio_next_folio(), and with CONFIG_BTRFS_ASSERT disabled (default) folio_size(NULL) faults. BUG: KASAN: null-ptr-deref in lzo_decompress_bio (fs/btrfs/lzo.c:383) Read of size 8 at addr 0000000000000000 by task kworker/u8:1/29 Workqueue: btrfs-endio simple_end_io_work kasan_report (mm/kasan/report.c:590) lzo_decompress_bio (fs/btrfs/lzo.c:383) end_bbio_compressed_read (fs/btrfs/compression.c:1065) btrfs_bio_end_io (fs/btrfs/bio.c:135) btrfs_check_read_bio (fs/btrfs/bio.c:180 fs/btrfs/bio.c:285) simple_end_io_work process_one_work worker_thread Reject any segment whose payload would extend beyond compressed_len before copying it, treating it as corruption like the other on-disk validation failures in this function. Reported-by: Xiang Mei Fixes: a6e66e6f8c1b ("btrfs: rework lzo_decompress_bio() to make it subpage compatible") Assisted-by: Claude:claude-opus-4-8 Reviewed-by: Qu Wenruo Signed-off-by: Weiming Shi Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/lzo.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c index 0d136da8b6be1..f2097e7cab435 100644 --- a/fs/btrfs/lzo.c +++ b/fs/btrfs/lzo.c @@ -400,6 +400,17 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb) return -EIO; } + /* The segment must not extend beyond the compressed input. */ + if (unlikely(cur_in + seg_len > cb->compressed_len)) { + struct btrfs_inode *inode = cb->bbio.inode; + + btrfs_err(fs_info, + "lzo segment overflows compressed input, root %llu inode %llu offset %llu cur_in %u len %u compressed len %u", + btrfs_root_id(inode->root), btrfs_ino(inode), + cb->start, cur_in, seg_len, cb->compressed_len); + return -EUCLEAN; + } + /* Copy the compressed segment payload into workspace */ copy_compressed_segment(cb, workspace->cbuf, seg_len, &cur_in); -- 2.53.0