From: Jeremy Cline <jcline@redhat.com>
To: Jan Kara <jack@suse.com>
Cc: linux-kernel@vger.kernel.org,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jeremy Cline <jcline@redhat.com>,
stable@vger.kernel.org
Subject: [PATCH 2/2] fs/quota: Fix spectre gadget in do_quotactl
Date: Tue, 31 Jul 2018 01:37:31 +0000 [thread overview]
Message-ID: <20180731013731.1987-3-jcline@redhat.com> (raw)
In-Reply-To: <20180731013731.1987-1-jcline@redhat.com>
'type' is user-controlled, so sanitize it after the bounds check to
avoid using it in speculative execution. This covers the following
potential gadgets detected with the help of smatch:
* fs/ext4/super.c:5741 ext4_quota_read() warn: potential spectre issue
'sb_dqopt(sb)->files' [r]
* fs/ext4/super.c:5778 ext4_quota_write() warn: potential spectre issue
'sb_dqopt(sb)->files' [r]
* fs/f2fs/super.c:1552 f2fs_quota_read() warn: potential spectre issue
'sb_dqopt(sb)->files' [r]
* fs/f2fs/super.c:1608 f2fs_quota_write() warn: potential spectre issue
'sb_dqopt(sb)->files' [r]
* fs/quota/dquot.c:412 mark_info_dirty() warn: potential spectre issue
'sb_dqopt(sb)->info' [w]
* fs/quota/dquot.c:933 dqinit_needed() warn: potential spectre issue
'dquots' [r]
* fs/quota/dquot.c:2112 dquot_commit_info() warn: potential spectre
issue 'dqopt->ops' [r]
* fs/quota/dquot.c:2362 vfs_load_quota_inode() warn: potential spectre
issue 'dqopt->files' [w] (local cap)
* fs/quota/dquot.c:2369 vfs_load_quota_inode() warn: potential spectre
issue 'dqopt->ops' [w] (local cap)
* fs/quota/dquot.c:2370 vfs_load_quota_inode() warn: potential spectre
issue 'dqopt->info' [w] (local cap)
* fs/quota/quota.c:110 quota_getfmt() warn: potential spectre issue
'sb_dqopt(sb)->info' [r]
* fs/quota/quota_v2.c:84 v2_check_quota_file() warn: potential spectre
issue 'quota_magics' [w]
* fs/quota/quota_v2.c:85 v2_check_quota_file() warn: potential spectre
issue 'quota_versions' [w]
* fs/quota/quota_v2.c:96 v2_read_file_info() warn: potential spectre
issue 'dqopt->info' [r]
* fs/quota/quota_v2.c:172 v2_write_file_info() warn: potential spectre
issue 'dqopt->info' [r]
Additionally, a quick inspection indicates there are array accesses with
'type' in quota_on() and quota_off() functions which are also addressed
by this.
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Cline <jcline@redhat.com>
---
This patch isn't going to cleanly apply to stable without the "fs/quota:
Replace XQM_MAXQUOTAS usage with MAXQUOTAS" patch, but I'm not sure that
patch is really stable material and XQM_MAXQUOTAS has been 3 since
pre-v4.4 so the end result will be the same even if that patch isn't
backported.
fs/quota/quota.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index d403392d8a0f..f0cbf58ad4da 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -18,6 +18,7 @@
#include <linux/quotaops.h>
#include <linux/types.h>
#include <linux/writeback.h>
+#include <linux/nospec.h>
static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
qid_t id)
@@ -701,6 +702,7 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
if (type >= MAXQUOTAS)
return -EINVAL;
+ type = array_index_nospec(type, MAXQUOTAS);
/*
* Quota not supported on this fs? Check this before s_quota_types
* since they needn't be set if quota is not supported at all.
--
2.17.1
next prev parent reply other threads:[~2018-07-31 1:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-31 1:37 [PATCH 0/2] fs/quota: Fix potential spectre v1 gadgets Jeremy Cline
2018-07-31 1:37 ` [PATCH 1/2] fs/quota: Replace XQM_MAXQUOTAS usage with MAXQUOTAS Jeremy Cline
2018-08-22 16:05 ` Jan Kara
2018-08-22 16:17 ` Jan Kara
2018-07-31 1:37 ` Jeremy Cline [this message]
2018-08-22 16:08 ` [PATCH 2/2] fs/quota: Fix spectre gadget in do_quotactl Jan Kara
2018-07-31 18:43 ` [PATCH 0/2] fs/quota: Fix potential spectre v1 gadgets Josh Poimboeuf
2018-08-22 16:12 ` Jan Kara
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180731013731.1987-3-jcline@redhat.com \
--to=jcline@redhat.com \
--cc=jack@suse.com \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).