From: Kees Cook <keescook@chromium.org>
To: kernel-hardening@lists.openwall.com
Cc: Kees Cook <keescook@chromium.org>,
Mark Rutland <mark.rutland@arm.com>,
Andy Lutomirski <luto@kernel.org>,
Hoeun Ryu <hoeun.ryu@gmail.com>, PaX Team <pageexec@freemail.hu>,
Emese Revfy <re.emese@gmail.com>,
Russell King <linux@armlinux.org.uk>,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: [RFC v2][PATCH 11/11] cgroups: force all struct cftype const
Date: Wed, 29 Mar 2017 11:16:03 -0700 [thread overview]
Message-ID: <1490811363-93944-12-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1490811363-93944-1-git-send-email-keescook@chromium.org>
As found in PaX, mark struct cftype with __do_const and add helpers
to deal with rare writes. This is a more complex example of a write-rarely
structure, which needs to use list helpers and blocks of begin/end pairs
to perform the needed updates.
With this change and the constify plugin enabled, the before/after
section byte sizes show:
before:
rodata: 0x2cc2f0
data: 0x130d00
after:
rodata: 0x2cf2f0 (+74478)
data: 0x12e5c0 (-65710)
Signed-off-by: Kees Cook <keescook@chromium.org>
---
include/linux/cgroup-defs.h | 2 +-
kernel/cgroup/cgroup.c | 35 +++++++++++++++++++++++------------
2 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 6a3f850cabab..67563a80d01f 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -434,7 +434,7 @@ struct cftype {
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lock_class_key lockdep_key;
#endif
-};
+} __do_const;
/*
* Control Group subsystem type.
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 48851327a15e..94188df45f96 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -3058,11 +3058,11 @@ static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp,
int ret;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
- key = &cft->lockdep_key;
+ key = (struct lock_class_key *)&cft->lockdep_key;
#endif
kn = __kernfs_create_file(cgrp->kn, cgroup_file_name(cgrp, cft, name),
- cgroup_file_mode(cft), 0, cft->kf_ops, cft,
- NULL, key);
+ cgroup_file_mode(cft), 0, cft->kf_ops,
+ (void *)cft, NULL, key);
if (IS_ERR(kn))
return PTR_ERR(kn);
@@ -3165,11 +3165,16 @@ static void cgroup_exit_cftypes(struct cftype *cfts)
/* free copy for custom atomic_write_len, see init_cftypes() */
if (cft->max_write_len && cft->max_write_len != PAGE_SIZE)
kfree(cft->kf_ops);
- cft->kf_ops = NULL;
- cft->ss = NULL;
+
+ rare_write_begin();
+ __rare_write(cft->kf_ops, NULL);
+ __rare_write(cft->ss, NULL);
/* revert flags set by cgroup core while adding @cfts */
- cft->flags &= ~(__CFTYPE_ONLY_ON_DFL | __CFTYPE_NOT_ON_DFL);
+ __rare_write(cft->flags,
+ cft->flags & ~(__CFTYPE_ONLY_ON_DFL |
+ __CFTYPE_NOT_ON_DFL));
+ rare_write_end();
}
}
@@ -3200,8 +3205,10 @@ static int cgroup_init_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
kf_ops->atomic_write_len = cft->max_write_len;
}
- cft->kf_ops = kf_ops;
- cft->ss = ss;
+ rare_write_begin();
+ __rare_write(cft->kf_ops, kf_ops);
+ __rare_write(cft->ss, ss);
+ rare_write_end();
}
return 0;
@@ -3214,7 +3221,7 @@ static int cgroup_rm_cftypes_locked(struct cftype *cfts)
if (!cfts || !cfts[0].ss)
return -ENOENT;
- list_del(&cfts->node);
+ rare_list_del(&cfts->node);
cgroup_apply_cftypes(cfts, false);
cgroup_exit_cftypes(cfts);
return 0;
@@ -3271,7 +3278,7 @@ static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
mutex_lock(&cgroup_mutex);
- list_add_tail(&cfts->node, &ss->cfts);
+ rare_list_add_tail(&cfts->node, &ss->cfts);
ret = cgroup_apply_cftypes(cfts, true);
if (ret)
cgroup_rm_cftypes_locked(cfts);
@@ -3292,8 +3299,10 @@ int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
struct cftype *cft;
+ rare_write_begin();
for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
- cft->flags |= __CFTYPE_ONLY_ON_DFL;
+ __rare_write(cft->flags, cft->flags | __CFTYPE_ONLY_ON_DFL);
+ rare_write_end();
return cgroup_add_cftypes(ss, cfts);
}
@@ -3309,8 +3318,10 @@ int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
struct cftype *cft;
+ rare_write_begin();
for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
- cft->flags |= __CFTYPE_NOT_ON_DFL;
+ __rare_write(cft->flags, cft->flags | __CFTYPE_NOT_ON_DFL);
+ rare_write_end();
return cgroup_add_cftypes(ss, cfts);
}
--
2.7.4
next prev parent reply other threads:[~2017-03-29 18:17 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 18:15 [RFC v2] Introduce rare_write() infrastructure Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 01/11] " Kees Cook
2017-03-29 18:23 ` Kees Cook
2017-03-30 7:44 ` Ho-Eun Ryu
2017-03-30 17:02 ` Kees Cook
2017-04-07 8:09 ` Ho-Eun Ryu
2017-04-07 20:38 ` Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 02/11] lkdtm: add test for " Kees Cook
2017-03-30 9:34 ` [kernel-hardening] " Ian Campbell
2017-03-30 16:16 ` Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 03/11] net: switch sock_diag handlers to rare_write() Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() Kees Cook
2017-03-29 22:38 ` Andy Lutomirski
2017-03-30 1:41 ` Kees Cook
2017-04-05 23:57 ` Andy Lutomirski
2017-04-06 0:14 ` Kees Cook
2017-04-06 15:59 ` Andy Lutomirski
2017-04-07 8:34 ` [kernel-hardening] " Mathias Krause
2017-04-07 9:46 ` Thomas Gleixner
2017-04-07 10:51 ` Mathias Krause
2017-04-07 13:14 ` Thomas Gleixner
2017-04-07 13:30 ` Mathias Krause
2017-04-07 16:14 ` Andy Lutomirski
2017-04-07 16:22 ` Mark Rutland
2017-04-07 19:58 ` PaX Team
2017-04-08 4:58 ` Andy Lutomirski
2017-04-09 12:47 ` PaX Team
2017-04-10 0:10 ` Andy Lutomirski
2017-04-10 10:42 ` PaX Team
2017-04-10 16:01 ` Andy Lutomirski
2017-04-07 20:44 ` Thomas Gleixner
2017-04-07 21:20 ` Kees Cook
2017-04-08 4:12 ` Daniel Micay
2017-04-08 4:13 ` Daniel Micay
2017-04-08 4:21 ` Daniel Micay
2017-04-08 5:07 ` Andy Lutomirski
2017-04-08 7:33 ` Daniel Micay
2017-04-08 15:20 ` Andy Lutomirski
2017-04-09 10:53 ` Ingo Molnar
2017-04-10 10:22 ` Mark Rutland
2017-04-09 20:24 ` PaX Team
2017-04-10 0:31 ` Andy Lutomirski
2017-04-10 19:47 ` PaX Team
2017-04-10 20:27 ` Andy Lutomirski
2017-04-10 20:13 ` Kees Cook
2017-04-10 20:17 ` Andy Lutomirski
2017-04-07 19:25 ` Thomas Gleixner
2017-04-07 14:45 ` Peter Zijlstra
2017-04-10 10:29 ` Mark Rutland
2017-04-07 19:52 ` PaX Team
2017-04-10 8:26 ` Thomas Gleixner
2017-04-10 19:55 ` PaX Team
2017-04-07 9:37 ` Peter Zijlstra
2017-03-29 18:15 ` [RFC v2][PATCH 05/11] ARM: mm: dump: Add domain to output Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 06/11] ARM: domains: Extract common USER domain init Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 07/11] ARM: mm: set DOMAIN_WR_RARE for rodata Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 08/11] ARM: Implement __arch_rare_write_begin/end() Kees Cook
2017-04-07 9:36 ` Peter Zijlstra
2017-03-29 18:16 ` [RFC v2][PATCH 09/11] list: add rare_write() list helpers Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 10/11] gcc-plugins: Add constify plugin Kees Cook
2017-03-29 18:16 ` Kees Cook [this message]
2017-03-29 19:00 ` [RFC v2] Introduce rare_write() infrastructure Russell King - ARM Linux
2017-03-29 19:14 ` Kees Cook
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