From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BEE312FB2; Tue, 27 Aug 2024 15:00:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724770844; cv=none; b=fb/JXho6Rz//+3k5eSEIQmcNCiowj+hZNt3Fsz+j3E5OPPxZ57s1JvylwPBRN/DsKJHhmUpARDn7kWEU+J9MrfsHKnzJxo3/hM2fOnBWV9np3vU3CjwuV7V5bGUkEokE/Mu0nw/tt7AemYj+/52WKCIZ3hmdd4iT1WmFtf3mR5Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724770844; c=relaxed/simple; bh=sFJeuR4sFq/idfHWd5keen4ThVYMYG6XQQzmqc10W4E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KVS+GkmCMJ/6YKFs4qxbeKOMGKWJhgfSutUF+pUmP/IOZV96kmOhm3LPRVwvs9qko+pXU9PKFCueBNQIG645lBCmBVJK4coKxfl2xCNjyh9sBldDdxq9Ct3KiAdfspccd2BMn0/yY39KgiW8Q8z0jNo3xgAkwOsyefuInGZIQEY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yQko5P2D; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="yQko5P2D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FFE3C4AF1C; Tue, 27 Aug 2024 15:00:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1724770844; bh=sFJeuR4sFq/idfHWd5keen4ThVYMYG6XQQzmqc10W4E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yQko5P2DXrMmaMpbGS243JRFRtBRT4EPA28k95okWri0uOc/5ECRm89Ih7whA9Pag hCi/GwoU7kmqgOEL/PgEOFeik8Yn+Ux7MSJBku/RHiKk7iCdRapnGthWH+LoGvOaYj eX3cxstHxUPXniXDat91NTOpNNq5Jz6N3tuOEPV8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Jann Horn , Linus Torvalds Subject: [PATCH 6.10 010/273] fuse: Initialize beyond-EOF page contents before setting uptodate Date: Tue, 27 Aug 2024 16:35:34 +0200 Message-ID: <20240827143833.776213027@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240827143833.371588371@linuxfoundation.org> References: <20240827143833.371588371@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jann Horn commit 3c0da3d163eb32f1f91891efaade027fa9b245b9 upstream. fuse_notify_store(), unlike fuse_do_readpage(), does not enable page zeroing (because it can be used to change partial page contents). So fuse_notify_store() must be more careful to fully initialize page contents (including parts of the page that are beyond end-of-file) before marking the page uptodate. The current code can leave beyond-EOF page contents uninitialized, which makes these uninitialized page contents visible to userspace via mmap(). This is an information leak, but only affects systems which do not enable init-on-alloc (via CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y or the corresponding kernel command line parameter). Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=2574 Cc: stable@kernel.org Fixes: a1d75f258230 ("fuse: add store request") Signed-off-by: Jann Horn Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/fuse/dev.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1618,9 +1618,11 @@ static int fuse_notify_store(struct fuse this_num = min_t(unsigned, num, PAGE_SIZE - offset); err = fuse_copy_page(cs, &page, offset, this_num, 0); - if (!err && offset == 0 && - (this_num == PAGE_SIZE || file_size == end)) + if (!PageUptodate(page) && !err && offset == 0 && + (this_num == PAGE_SIZE || file_size == end)) { + zero_user_segment(page, this_num, PAGE_SIZE); SetPageUptodate(page); + } unlock_page(page); put_page(page);