From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Will Deacon <will@kernel.org>, Eric Dumazet <edumazet@google.com>,
Jann Horn <jannh@google.com>, Kees Cook <keescook@chromium.org>,
Maddie Stone <maddiestone@google.com>,
Marco Elver <elver@google.com>,
"Paul E . McKenney" <paulmck@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
kernel-team@android.com, kernel-hardening@lists.openwall.com
Subject: [RFC PATCH 13/21] list: Add integrity checking to hlist_nulls implementation
Date: Tue, 24 Mar 2020 15:36:35 +0000 [thread overview]
Message-ID: <20200324153643.15527-14-will@kernel.org> (raw)
In-Reply-To: <20200324153643.15527-1-will@kernel.org>
Extend the 'hlist_nulls' implementation so that it can optionally
perform integrity checking in a similar fashion to the standard 'list'
code when CONFIG_CHECK_INTEGRITY_LIST=y.
On architectures without a trap value for ILLEGAL_POINTER_VALUE (i.e.
all 32-bit architectures), explicit pointer/poison checks can help to
mitigate UAF vulnerabilities such as the one exploited by "pingpongroot"
(CVE-2015-3636).
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
include/linux/list_nulls.h | 23 +++++++++++++++++++
lib/list_debug.c | 47 ++++++++++++++++++++++++++++++++++++++
2 files changed, 70 insertions(+)
diff --git a/include/linux/list_nulls.h b/include/linux/list_nulls.h
index 48f33ae16381..379e097e92b0 100644
--- a/include/linux/list_nulls.h
+++ b/include/linux/list_nulls.h
@@ -35,6 +35,23 @@ struct hlist_nulls_node {
({ typeof(ptr) ____ptr = (ptr); \
!is_a_nulls(____ptr) ? hlist_nulls_entry(____ptr, type, member) : NULL; \
})
+
+#ifdef CONFIG_CHECK_INTEGRITY_LIST
+extern bool __hlist_nulls_add_head_valid(struct hlist_nulls_node *new,
+ struct hlist_nulls_head *head);
+extern bool __hlist_nulls_del_valid(struct hlist_nulls_node *node);
+#else
+static inline bool __hlist_nulls_add_head_valid(struct hlist_nulls_node *new,
+ struct hlist_nulls_head *head)
+{
+ return true;
+}
+static inline bool __hlist_nulls_del_valid(struct hlist_nulls_node *node)
+{
+ return true;
+}
+#endif
+
/**
* ptr_is_a_nulls - Test if a ptr is a nulls
* @ptr: ptr to be tested
@@ -79,6 +96,9 @@ static inline void hlist_nulls_add_head(struct hlist_nulls_node *n,
{
struct hlist_nulls_node *first = h->first;
+ if (!__hlist_nulls_add_head_valid(n, h))
+ return;
+
n->next = first;
n->pprev = &h->first;
h->first = n;
@@ -91,6 +111,9 @@ static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
struct hlist_nulls_node *next = n->next;
struct hlist_nulls_node **pprev = n->pprev;
+ if (!__hlist_nulls_del_valid(n))
+ return;
+
WRITE_ONCE(*pprev, next);
if (!is_a_nulls(next))
WRITE_ONCE(next->pprev, pprev);
diff --git a/lib/list_debug.c b/lib/list_debug.c
index 03234ebd18c9..b3560de4accc 100644
--- a/lib/list_debug.c
+++ b/lib/list_debug.c
@@ -10,6 +10,7 @@
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/rculist.h>
+#include <linux/rculist_nulls.h>
/*
* Check that the data structures for the list manipulations are reasonably
@@ -139,3 +140,49 @@ bool __hlist_del_valid(struct hlist_node *node)
return true;
}
EXPORT_SYMBOL(__hlist_del_valid);
+
+bool __hlist_nulls_add_head_valid(struct hlist_nulls_node *new,
+ struct hlist_nulls_head *head)
+{
+ struct hlist_nulls_node *first = head->first;
+
+ if (CHECK_DATA_CORRUPTION(!is_a_nulls(first) &&
+ first->pprev != &head->first,
+ "hlist_nulls_add_head corruption: first->pprev should be &head->first (%px), but was %px (first=%px)",
+ &head->first, first->pprev, first) ||
+ CHECK_DATA_CORRUPTION(new == first,
+ "hlist_nulls_add_head double add: new (%px) == first (%px)",
+ new, first))
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL(__hlist_nulls_add_head_valid);
+
+bool __hlist_nulls_del_valid(struct hlist_nulls_node *node)
+{
+ struct hlist_nulls_node *prev, *next = node->next;
+
+ if (CHECK_DATA_CORRUPTION(next == LIST_POISON1,
+ "hlist_nulls_del corruption: %px->next is LIST_POISON1 (%px)\n",
+ node, LIST_POISON1) ||
+ CHECK_DATA_CORRUPTION(node->pprev == LIST_POISON2,
+ "hlist_nulls_del corruption: %px->pprev is LIST_POISON2 (%px)\n",
+ node, LIST_POISON2))
+ return false;
+
+ BUILD_BUG_ON(offsetof(struct hlist_nulls_node, next) !=
+ offsetof(struct hlist_nulls_head, first));
+ prev = container_of(node->pprev, struct hlist_nulls_node, next);
+ if (CHECK_DATA_CORRUPTION(prev->next != node,
+ "hlist_nulls_del corruption: prev->next should be %px, but was %px\n",
+ node, prev->next) ||
+ CHECK_DATA_CORRUPTION(!is_a_nulls(next) &&
+ next->pprev != &node->next,
+ "hlist_nulls_del corruption: next->pprev should be %px, but was %px\n",
+ &node->next, next->pprev))
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL(__hlist_nulls_del_valid);
--
2.20.1
next prev parent reply other threads:[~2020-03-24 15:38 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 15:36 [RFC PATCH 00/21] Improve list integrity checking Will Deacon
2020-03-24 15:36 ` [RFC PATCH 01/21] list: Remove hlist_unhashed_lockless() Will Deacon
2020-03-24 16:27 ` Greg KH
2020-03-30 23:05 ` Paul E. McKenney
2020-03-24 15:36 ` [RFC PATCH 02/21] list: Remove hlist_nulls_unhashed_lockless() Will Deacon
2020-03-24 16:27 ` Greg KH
2020-03-30 23:07 ` Paul E. McKenney
2020-03-24 15:36 ` [RFC PATCH 03/21] list: Annotate lockless list primitives with data_race() Will Deacon
2020-03-24 16:20 ` Jann Horn
2020-03-24 16:26 ` Greg KH
2020-03-24 16:38 ` Jann Horn
2020-03-24 16:59 ` Greg KH
2020-03-24 18:22 ` Jann Horn
2020-03-24 16:23 ` Marco Elver
2020-03-24 21:33 ` Will Deacon
2020-03-31 13:10 ` Will Deacon
2020-04-01 6:34 ` Marco Elver
2020-04-01 8:40 ` Will Deacon
2020-05-08 13:46 ` [tip: locking/kcsan] kcsan: Change data_race() to no longer require marking racing accesses tip-bot2 for Marco Elver
2020-03-24 16:51 ` [RFC PATCH 03/21] list: Annotate lockless list primitives with data_race() Peter Zijlstra
2020-03-24 16:56 ` Jann Horn
2020-03-24 21:32 ` Will Deacon
2020-03-30 23:13 ` Paul E. McKenney
2020-04-24 17:39 ` Will Deacon
2020-04-27 19:24 ` Paul E. McKenney
2020-03-24 15:36 ` [RFC PATCH 04/21] timers: Use hlist_unhashed() instead of open-coding in timer_pending() Will Deacon
2020-03-24 16:30 ` Greg KH
2020-03-24 15:36 ` [RFC PATCH 05/21] list: Comment missing WRITE_ONCE() in __list_del() Will Deacon
2020-03-30 23:14 ` Paul E. McKenney
2020-03-24 15:36 ` [RFC PATCH 06/21] list: Remove superfluous WRITE_ONCE() from hlist_nulls implementation Will Deacon
2020-03-30 23:21 ` Paul E. McKenney
2020-03-24 15:36 ` [RFC PATCH 07/21] Revert "list: Use WRITE_ONCE() when adding to lists and hlists" Will Deacon
2020-03-30 23:19 ` Paul E. McKenney
2020-03-24 15:36 ` [RFC PATCH 08/21] Revert "list: Use WRITE_ONCE() when initializing list_head structures" Will Deacon
2020-03-30 23:25 ` Paul E. McKenney
2020-03-31 13:11 ` Will Deacon
2020-03-31 13:47 ` Paul E. McKenney
2020-03-24 15:36 ` [RFC PATCH 09/21] list: Remove unnecessary WRITE_ONCE() from hlist_bl_add_before() Will Deacon
2020-03-30 23:30 ` Paul E. McKenney
2020-03-31 12:37 ` Will Deacon
2020-03-24 15:36 ` [RFC PATCH 10/21] kernel-hacking: Make DEBUG_{LIST,PLIST,SG,NOTIFIERS} non-debug options Will Deacon
2020-03-24 16:42 ` Greg KH
2020-03-24 15:36 ` [RFC PATCH 11/21] list: Add integrity checking to hlist implementation Will Deacon
2020-03-24 15:36 ` [RFC PATCH 12/21] list: Poison ->next pointer for non-RCU deletion of 'hlist_nulls_node' Will Deacon
2020-03-30 23:32 ` Paul E. McKenney
2020-03-24 15:36 ` Will Deacon [this message]
2020-03-24 15:36 ` [RFC PATCH 14/21] plist: Use CHECK_DATA_CORRUPTION instead of explicit {BUG,WARN}_ON() Will Deacon
2020-03-24 16:42 ` Greg KH
2020-03-24 15:36 ` [RFC PATCH 15/21] list_bl: Use CHECK_DATA_CORRUPTION instead of custom BUG_ON() wrapper Will Deacon
2020-03-24 15:36 ` [RFC PATCH 16/21] list_bl: Extend integrity checking in deletion routines Will Deacon
2020-03-24 15:36 ` [RFC PATCH 17/21] linux/bit_spinlock.h: Include linux/processor.h Will Deacon
2020-03-24 16:28 ` Greg KH
2020-03-24 21:08 ` Will Deacon
2020-03-24 15:36 ` [RFC PATCH 18/21] list_bl: Move integrity checking out of line Will Deacon
2020-03-24 15:36 ` [RFC PATCH 19/21] list_bl: Extend integrity checking to cover the same cases as 'hlist' Will Deacon
2020-03-24 15:36 ` [RFC PATCH 20/21] list: Format CHECK_DATA_CORRUPTION error messages consistently Will Deacon
2020-03-24 16:40 ` Greg KH
2020-03-24 15:36 ` [RFC PATCH 21/21] lkdtm: Extend list corruption checks Will Deacon
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