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Date: Tue, 10 Jul 2018 13:23:33 -0700
From: tip-bot for Mathieu Desnoyers <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: torvalds@...ux-foundation.org, josh@...htriplett.org,
linux-kernel@...r.kernel.org, cl@...ux.com, andi@...stfloor.org,
joelaf@...gle.com, mingo@...nel.org, linux@....linux.org.uk,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
hpa@...or.com, catalin.marinas@....com, mtk.manpages@...il.com,
bmaurer@...com, boqun.feng@...il.com, peterz@...radead.org,
pjt@...gle.com, paulmck@...ux.vnet.ibm.com, davejwatson@...com,
tglx@...utronix.de, rostedt@...dmis.org, will.deacon@....com,
luto@...capital.net
Subject: [tip:core/urgent] rseq: uapi: Declare rseq_cs field as union,
update includes
Commit-ID: ec9c82e03a744e5698bd95eab872855861a821fa
Gitweb: https://git.kernel.org/tip/ec9c82e03a744e5698bd95eab872855861a821fa
Author: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
AuthorDate: Mon, 9 Jul 2018 15:51:53 -0400
Committer: Thomas Gleixner <tglx@...utronix.de>
CommitDate: Tue, 10 Jul 2018 22:18:52 +0200
rseq: uapi: Declare rseq_cs field as union, update includes
Declaring the rseq_cs field as a union between __u64 and two __u32
allows both 32-bit and 64-bit kernels to read the full __u64, and
therefore validate that a 32-bit user-space cleared the upper 32
bits, thus ensuring a consistent behavior between native 32-bit
kernels and 32-bit compat tasks on 64-bit kernels.
Check that the rseq_cs value read is < TASK_SIZE.
The asm/byteorder.h header needs to be included by rseq.h, now
that it is not using linux/types_32_64.h anymore.
Considering that only __32 and __u64 types are declared in linux/rseq.h,
the linux/types.h header should always be included for both kernel and
user-space code: including stdint.h is just for u64 and u32, which are
not used in this header at all.
Use copy_from_user()/clear_user() to interact with a 64-bit field,
because arm32 does not implement 64-bit __get_user, and ppc32 does not
64-bit get_user. Considering that the rseq_cs pointer does not need to
be loaded/stored with single-copy atomicity from the kernel anymore, we
can simply use copy_from_user()/clear_user().
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-api@...r.kernel.org
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: "Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>
Cc: Boqun Feng <boqun.feng@...il.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Dave Watson <davejwatson@...com>
Cc: Paul Turner <pjt@...gle.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Russell King <linux@....linux.org.uk>
Cc: "H . Peter Anvin" <hpa@...or.com>
Cc: Andi Kleen <andi@...stfloor.org>
Cc: Chris Lameter <cl@...ux.com>
Cc: Ben Maurer <bmaurer@...com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Josh Triplett <josh@...htriplett.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will.deacon@....com>
Cc: Michael Kerrisk <mtk.manpages@...il.com>
Cc: Joel Fernandes <joelaf@...gle.com>
Cc: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Link: https://lkml.kernel.org/r/20180709195155.7654-5-mathieu.desnoyers@efficios.com
---
include/uapi/linux/rseq.h | 27 +++++++++++++++++++--------
kernel/rseq.c | 15 +++++++++------
tools/testing/selftests/rseq/rseq.h | 11 ++++++++++-
3 files changed, 38 insertions(+), 15 deletions(-)
diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h
index bf4188c13bec..9a402fdb60e9 100644
--- a/include/uapi/linux/rseq.h
+++ b/include/uapi/linux/rseq.h
@@ -10,13 +10,8 @@
* Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
*/
-#ifdef __KERNEL__
-# include <linux/types.h>
-#else
-# include <stdint.h>
-#endif
-
-#include <linux/types_32_64.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
enum rseq_cpu_id_state {
RSEQ_CPU_ID_UNINITIALIZED = -1,
@@ -111,7 +106,23 @@ struct rseq {
* atomicity semantics. This field should only be updated by the
* thread which registered this data structure. Aligned on 64-bit.
*/
- LINUX_FIELD_u32_u64(rseq_cs);
+ union {
+ __u64 ptr64;
+#ifdef __LP64__
+ __u64 ptr;
+#else
+ struct {
+#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN)
+ __u32 padding; /* Initialized to zero. */
+ __u32 ptr32;
+#else /* LITTLE */
+ __u32 ptr32;
+ __u32 padding; /* Initialized to zero. */
+#endif /* ENDIAN */
+ } ptr;
+#endif
+ } rseq_cs;
+
/*
* Restartable sequences flags field.
*
diff --git a/kernel/rseq.c b/kernel/rseq.c
index 2a7748675be7..c6242d8594dc 100644
--- a/kernel/rseq.c
+++ b/kernel/rseq.c
@@ -115,19 +115,20 @@ static int rseq_reset_rseq_cpu_id(struct task_struct *t)
static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
{
struct rseq_cs __user *urseq_cs;
- unsigned long ptr;
+ u64 ptr;
u32 __user *usig;
u32 sig;
int ret;
- ret = get_user(ptr, &t->rseq->rseq_cs);
- if (ret)
- return ret;
+ if (copy_from_user(&ptr, &t->rseq->rseq_cs.ptr64, sizeof(ptr)))
+ return -EFAULT;
if (!ptr) {
memset(rseq_cs, 0, sizeof(*rseq_cs));
return 0;
}
- urseq_cs = (struct rseq_cs __user *)ptr;
+ if (ptr >= TASK_SIZE)
+ return -EINVAL;
+ urseq_cs = (struct rseq_cs __user *)(unsigned long)ptr;
if (copy_from_user(rseq_cs, urseq_cs, sizeof(*rseq_cs)))
return -EFAULT;
@@ -203,7 +204,9 @@ static int clear_rseq_cs(struct task_struct *t)
*
* Set rseq_cs to NULL.
*/
- return put_user(0UL, &t->rseq->rseq_cs);
+ if (clear_user(&t->rseq->rseq_cs.ptr64, sizeof(t->rseq->rseq_cs.ptr64)))
+ return -EFAULT;
+ return 0;
}
/*
diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h
index a4684112676c..f2073cfa4448 100644
--- a/tools/testing/selftests/rseq/rseq.h
+++ b/tools/testing/selftests/rseq/rseq.h
@@ -133,6 +133,15 @@ static inline uint32_t rseq_current_cpu(void)
return cpu;
}
+static inline void rseq_clear_rseq_cs(void)
+{
+#ifdef __LP64__
+ __rseq_abi.rseq_cs.ptr = 0;
+#else
+ __rseq_abi.rseq_cs.ptr.ptr32 = 0;
+#endif
+}
+
/*
* rseq_prepare_unload() should be invoked by each thread using rseq_finish*()
* at least once between their last rseq_finish*() and library unload of the
@@ -143,7 +152,7 @@ static inline uint32_t rseq_current_cpu(void)
*/
static inline void rseq_prepare_unload(void)
{
- __rseq_abi.rseq_cs = 0;
+ rseq_clear_rseq_cs();
}
#endif /* RSEQ_H_ */
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