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 EB01C37DE9B; Thu, 20 Aug 2026 17:40:40 +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=1787247642; cv=none; b=HVUtzQBshSBDhBp2DHEmr22bVzrcdgfQXQqQfGEUQAWP+NQD/c//ugJrP+JQq+1zy+mg3CYT93TdeQ1ymDr2Yojpb6WbrMrN2XF+CB9cuZFjP+5a7R7xf5j9jieoZGUWxOMhYqfMdFhECWvuaZ1dhVPPhqRTfTfdPWmVntsSeNo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787247642; c=relaxed/simple; bh=YiPAOPZSUp9AbMsROkVkgsJ47YXdyrMkWsEjdRzXbiU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=erpYQZG/tn3u5FyrfuJuo+XXxeF0zRxmMOx2RCwWRyC/joRSKDq+j/q6KCazIlocW2tNkLbP6qer2Y+ElafvjunDmugH/vCVXQm0LSauOzZvCbjEw0lT9Uah5l68CYqMF1Yg4if1plXxqHSwbKYhfog3IULJxGx7JTyJnaCqgLw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cdatjWOk; 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="cdatjWOk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5753D1F000E9; Thu, 20 Aug 2026 17:40:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787247640; bh=5CLplC8oqKzwbSHSMoxnXcTdGuVA35IN5BnwqR42K+E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cdatjWOkiFejC6U4eY2xe4OUiGXmWbl8g54mal/kYFXgrKbXifSdiHUDAXtfj7Znb 8DiUFymnOi7gz2tNIh12Lv77QoRLyPXW2b2Qa/XOSWolGo7qoEoEofnWXQTffNf+Xq hdUiUQVwM2ZDBdKd5DdZH5kfuHh/GyBHhQRNutU8= 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)" , Sasha Levin Subject: [PATCH 6.6 078/166] iomap: fix out-of-bounds bitmap_set() with zero-length range Date: Thu, 20 Aug 2026 16:55:37 +0200 Message-ID: <20260820145213.494048060@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145211.194104353@linuxfoundation.org> References: <20260820145211.194104353@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhang Yi [ Upstream commit 9c7d8f7c8994c790fca501dc45ce66e7356cbe05 ] 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: Sasha Levin 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 @@ -61,11 +61,13 @@ 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); } @@ -127,13 +129,17 @@ 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); }