lkml.org 
[lkml]   [2021]   [Dec]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH v4 4/7] uaccess-buffer: add CONFIG_GENERIC_ENTRY support
From
Add uaccess logging support on architectures that use
CONFIG_GENERIC_ENTRY (currently only s390 and x86).

Link: https://linux-review.googlesource.com/id/I3c5eb19a7e4a1dbe6095f6971f7826c4b0663f7d
Signed-off-by: Peter Collingbourne <pcc@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
---
v4:
- move pre/post-exit-loop calls into if statement

arch/Kconfig | 1 +
include/linux/entry-common.h | 2 ++
include/linux/thread_info.h | 4 ++++
kernel/entry/common.c | 14 +++++++++++++-
4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 17819f53ea80..bc849a61b636 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -31,6 +31,7 @@ config HOTPLUG_SMT
bool

config GENERIC_ENTRY
+ select HAVE_ARCH_UACCESS_BUFFER
bool

config KPROBES
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index 2e2b8d6140ed..973fcd1d48a3 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -42,12 +42,14 @@
SYSCALL_WORK_SYSCALL_EMU | \
SYSCALL_WORK_SYSCALL_AUDIT | \
SYSCALL_WORK_SYSCALL_USER_DISPATCH | \
+ SYSCALL_WORK_UACCESS_BUFFER_ENTRY | \
ARCH_SYSCALL_WORK_ENTER)
#define SYSCALL_WORK_EXIT (SYSCALL_WORK_SYSCALL_TRACEPOINT | \
SYSCALL_WORK_SYSCALL_TRACE | \
SYSCALL_WORK_SYSCALL_AUDIT | \
SYSCALL_WORK_SYSCALL_USER_DISPATCH | \
SYSCALL_WORK_SYSCALL_EXIT_TRAP | \
+ SYSCALL_WORK_UACCESS_BUFFER_EXIT | \
ARCH_SYSCALL_WORK_EXIT)

/*
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index ad0c4e041030..b0f8ea86967f 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -46,6 +46,8 @@ enum syscall_work_bit {
SYSCALL_WORK_BIT_SYSCALL_AUDIT,
SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH,
SYSCALL_WORK_BIT_SYSCALL_EXIT_TRAP,
+ SYSCALL_WORK_BIT_UACCESS_BUFFER_ENTRY,
+ SYSCALL_WORK_BIT_UACCESS_BUFFER_EXIT,
};

#define SYSCALL_WORK_SECCOMP BIT(SYSCALL_WORK_BIT_SECCOMP)
@@ -55,6 +57,8 @@ enum syscall_work_bit {
#define SYSCALL_WORK_SYSCALL_AUDIT BIT(SYSCALL_WORK_BIT_SYSCALL_AUDIT)
#define SYSCALL_WORK_SYSCALL_USER_DISPATCH BIT(SYSCALL_WORK_BIT_SYSCALL_USER_DISPATCH)
#define SYSCALL_WORK_SYSCALL_EXIT_TRAP BIT(SYSCALL_WORK_BIT_SYSCALL_EXIT_TRAP)
+#define SYSCALL_WORK_UACCESS_BUFFER_ENTRY BIT(SYSCALL_WORK_BIT_UACCESS_BUFFER_ENTRY)
+#define SYSCALL_WORK_UACCESS_BUFFER_EXIT BIT(SYSCALL_WORK_BIT_UACCESS_BUFFER_EXIT)
#endif

#include <asm/thread_info.h>
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index d5a61d565ad5..59ec6e3f793b 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -6,6 +6,7 @@
#include <linux/livepatch.h>
#include <linux/audit.h>
#include <linux/tick.h>
+#include <linux/uaccess-buffer.h>

#include "common.h"

@@ -70,6 +71,9 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall,
return ret;
}

+ if (work & SYSCALL_WORK_UACCESS_BUFFER_ENTRY)
+ uaccess_buffer_syscall_entry();
+
/* Either of the above might have changed the syscall number */
syscall = syscall_get_nr(current, regs);

@@ -197,14 +201,19 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
static void exit_to_user_mode_prepare(struct pt_regs *regs)
{
unsigned long ti_work = READ_ONCE(current_thread_info()->flags);
+ bool uaccess_buffer_pending;

lockdep_assert_irqs_disabled();

/* Flush pending rcuog wakeup before the last need_resched() check */
tick_nohz_user_enter_prepare();

- if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
+ if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK)) {
+ bool uaccess_buffer_pending = uaccess_buffer_pre_exit_loop();
+
ti_work = exit_to_user_mode_loop(regs, ti_work);
+ uaccess_buffer_post_exit_loop(uaccess_buffer_pending);
+ }

arch_exit_to_user_mode_prepare(regs, ti_work);

@@ -247,6 +256,9 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long work)

audit_syscall_exit(regs);

+ if (work & SYSCALL_WORK_UACCESS_BUFFER_EXIT)
+ uaccess_buffer_syscall_exit();
+
if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT)
trace_sys_exit(regs, syscall_get_return_value(current, regs));

--
2.34.1.173.g76aa8bc2d0-goog
\
 
 \ /
  Last update: 2021-12-09 23:17    [W:0.178 / U:0.404 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site