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 219613A641D; Thu, 30 Jul 2026 15:20:26 +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=1785424827; cv=none; b=M2AYpQf7eGNTjANKCqJFK/zZ7Pg33sJwQKuXmC3BxeEuOf2ygoIFA4dMyxMmAimhvxPR3IOaa5/DgI0LocAFhGfOuy8Rc9Fat+nw6imVkEshEunYehSgbDQLFm/GH8P9QxI0NouPN8ou1+FhdJEpSrZypYUwljM8iZA9yFRY5h0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785424827; c=relaxed/simple; bh=pxZGuFgzGiUijtUJRMH8XoUhQLBPHg4tMREglngjkv4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=W+ZtMtk7fQeTeNka2Soec+e9V9NhS2QCgp7bqkPa6X8o7tVrWuYk7WK4J7GgzE/y8KPSTy0HmZJdIDid7aZSSWtzgHkzszXUBXx262r+P7iuixRbMSJBf733lNWFKBKx6Fc228ZAC4RXaCiH3OdVp54Defzjt9xPQCGeIhjOUd4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cvOOa6rd; 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="cvOOa6rd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6995C1F000E9; Thu, 30 Jul 2026 15:20:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785424826; bh=ykyhokto1pOXA9Gr2tHJqILCj/hyxPHl9gyCqc32BXE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cvOOa6rd8Py7dzV9iy+ylmQ2CQOB44Zgy2/XW5yH1DJ53nbptXJkQhwsdT/wQ0tlC 7JQlLLv1xwndDTcj9ukjrHubFIl5adeZNPoNIy4MEh6O5LGaQtyjdbso+PruOoTuOo /XG9JAFXVAkylFUR3xWevcQ2dpZH/J9oUubrvOAo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhang Yi , Joanne Koong , "Darrick J. Wong" , Christoph Hellwig , "Christian Brauner (Amutable)" Subject: [PATCH 6.18 530/675] iomap: fix out-of-bounds bitmap_set() with zero-length range Date: Thu, 30 Jul 2026 16:14:20 +0200 Message-ID: <20260730141456.407615352@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141445.110192266@linuxfoundation.org> References: <20260730141445.110192266@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhang Yi commit 9c7d8f7c8994c790fca501dc45ce66e7356cbe05 upstream. ifs_set_range_dirty() and ifs_set_range_uptodate() compute last_blk as (off + len - 1) >> i_blkbits. When off is 0 and len is 0, the unsigned subtraction underflows to SIZE_MAX, producing a huge last_blk and nr_blks value that causes bitmap_set() to write far beyond the ifs->state allocation. Regarding ifs_set_range_uptodate(), it is temporarily safe because len cannot be passed in as 0. However, for ifs_set_range_dirty() this is reachable from __iomap_write_end(): when copy_folio_from_iter_atomic() returns 0 (e.g. user buffer fault) and the folio is already uptodate, the guard at the top of __iomap_write_end() does not trigger because !folio_test_uptodate() is false, and iomap_set_range_dirty() is called with copied == 0. Add a !len guard to both functions before the computation, so that a zero-length range is a no-op. Fixes: 4ce02c679722 ("iomap: Add per-block dirty state tracking to improve performance") Cc: stable@vger.kernel.org # v6.6 Signed-off-by: Zhang Yi Link: https://patch.msgid.link/20260714082325.325163-5-yi.zhang@huaweicloud.com Reviewed-by: Joanne Koong Reviewed-by: "Darrick J. Wong" Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Amutable) Signed-off-by: Greg Kroah-Hartman --- fs/iomap/buffered-io.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -47,11 +47,13 @@ static bool ifs_set_range_uptodate(struc struct iomap_folio_state *ifs, size_t off, size_t len) { struct inode *inode = folio->mapping->host; - unsigned int first_blk = off >> inode->i_blkbits; - unsigned int last_blk = (off + len - 1) >> inode->i_blkbits; - unsigned int nr_blks = last_blk - first_blk + 1; + unsigned int first_blk, last_blk; - bitmap_set(ifs->state, first_blk, nr_blks); + if (len) { + first_blk = off >> inode->i_blkbits; + last_blk = (off + len - 1) >> inode->i_blkbits; + bitmap_set(ifs->state, first_blk, last_blk - first_blk + 1); + } return ifs_is_fully_uptodate(folio, ifs); } @@ -154,13 +156,17 @@ static void ifs_set_range_dirty(struct f { struct inode *inode = folio->mapping->host; unsigned int blks_per_folio = i_blocks_per_folio(inode, folio); - unsigned int first_blk = (off >> inode->i_blkbits); - unsigned int last_blk = (off + len - 1) >> inode->i_blkbits; - unsigned int nr_blks = last_blk - first_blk + 1; + unsigned int first_blk, last_blk; unsigned long flags; + if (!len) + return; + + first_blk = off >> inode->i_blkbits; + last_blk = (off + len - 1) >> inode->i_blkbits; spin_lock_irqsave(&ifs->state_lock, flags); - bitmap_set(ifs->state, first_blk + blks_per_folio, nr_blks); + bitmap_set(ifs->state, first_blk + blks_per_folio, + last_blk - first_blk + 1); spin_unlock_irqrestore(&ifs->state_lock, flags); }