[PATCH v6 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state

[Thomas Garnier]

Implement specific usage of verify_pre_usermode_state for user-mode
returns for arm.

Signed-off-by: Thomas Garnier 
---
Based on next-20170404
---
 arch/arm/Kconfig   |  1 +
 arch/arm/kernel/entry-common.S | 16 +++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2cec306c7390..e2ebc7d37742 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -12,6 +12,7 @@ config ARM
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_MIGHT_HAVE_PC_PARPORT
+   select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
select ARCH_SUPPORTS_ATOMIC_RMW
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index eb5cd77bf1d8..88c72c4e44ad 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -12,6 +12,7 @@
 #include 
 #include 
 #include 
+#include 
 #ifdef CONFIG_AEABI
 #include 
 #endif
@@ -27,7 +28,6 @@
 
 #include "entry-header.S"
 
-
.align  5
 #if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))
 /*
@@ -40,9 +40,12 @@ ret_fast_syscall:
  UNWIND(.fnstart   )
  UNWIND(.cantunwind)
disable_irq_notrace @ disable interrupts
+   ldr r2, [tsk, #TI_ADDR_LIMIT]
ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing
tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
bne fast_work_pending
+   cmp r2, #TASK_SIZE
+   blneaddr_limit_fail
 
/* perform architecture specific actions before user return */
arch_ret_to_user r1, lr
@@ -66,6 +69,7 @@ ret_fast_syscall:
  UNWIND(.cantunwind)
str r0, [sp, #S_R0 + S_OFF]!@ save returned r0
disable_irq_notrace @ disable interrupts
+   ldr r2, [tsk, #TI_ADDR_LIMIT]
ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing
tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
beq no_work_pending
@@ -82,6 +86,7 @@ slow_work_pending:
mov r2, why @ 'syscall'
bl  do_work_pending
cmp r0, #0
+   ldreq   r2, [tsk, #TI_ADDR_LIMIT]
beq no_work_pending
movlt   scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
ldmia   sp, {r0 - r6}   @ have to reload r0 - r6
@@ -99,9 +104,12 @@ ret_slow_syscall:
disable_irq_notrace @ disable interrupts
 ENTRY(ret_to_user_from_irq)
ldr r1, [tsk, #TI_FLAGS]
+   ldr r2, [tsk, #TI_ADDR_LIMIT]
tst r1, #_TIF_WORK_MASK
bne slow_work_pending
 no_work_pending:
+   cmp r2, #TASK_SIZE
+   blneaddr_limit_fail
asm_trace_hardirqs_on save = 0
 
/* perform architecture specific actions before user return */
@@ -125,6 +133,12 @@ ENTRY(ret_from_fork)
b   ret_slow_syscall
 ENDPROC(ret_from_fork)
 
+addr_limit_fail:
+   stmfd   sp!, {r0, lr}
+   bl  asm_verify_pre_usermode_state
+   ldmfd   sp!, {r0, lr}
+   ret lr
+
 /*=
  * SWI handler
  *-
-- 
2.12.2.715.g7642488e1d-goog

[PATCH v6 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state

[Thomas Garnier]

Implement specific usage of verify_pre_usermode_state for user-mode
returns for arm.

Signed-off-by: Thomas Garnier 
---
Based on next-20170404
---
 arch/arm/Kconfig   |  1 +
 arch/arm/kernel/entry-common.S | 16 +++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2cec306c7390..e2ebc7d37742 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -12,6 +12,7 @@ config ARM
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_MIGHT_HAVE_PC_PARPORT
+   select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
select ARCH_SUPPORTS_ATOMIC_RMW
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index eb5cd77bf1d8..88c72c4e44ad 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -12,6 +12,7 @@
 #include 
 #include 
 #include 
+#include 
 #ifdef CONFIG_AEABI
 #include 
 #endif
@@ -27,7 +28,6 @@
 
 #include "entry-header.S"
 
-
.align  5
 #if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))
 /*
@@ -40,9 +40,12 @@ ret_fast_syscall:
  UNWIND(.fnstart   )
  UNWIND(.cantunwind)
disable_irq_notrace @ disable interrupts
+   ldr r2, [tsk, #TI_ADDR_LIMIT]
ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing
tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
bne fast_work_pending
+   cmp r2, #TASK_SIZE
+   blneaddr_limit_fail
 
/* perform architecture specific actions before user return */
arch_ret_to_user r1, lr
@@ -66,6 +69,7 @@ ret_fast_syscall:
  UNWIND(.cantunwind)
str r0, [sp, #S_R0 + S_OFF]!@ save returned r0
disable_irq_notrace @ disable interrupts
+   ldr r2, [tsk, #TI_ADDR_LIMIT]
ldr r1, [tsk, #TI_FLAGS]@ re-check for syscall tracing
tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
beq no_work_pending
@@ -82,6 +86,7 @@ slow_work_pending:
mov r2, why @ 'syscall'
bl  do_work_pending
cmp r0, #0
+   ldreq   r2, [tsk, #TI_ADDR_LIMIT]
beq no_work_pending
movlt   scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
ldmia   sp, {r0 - r6}   @ have to reload r0 - r6
@@ -99,9 +104,12 @@ ret_slow_syscall:
disable_irq_notrace @ disable interrupts
 ENTRY(ret_to_user_from_irq)
ldr r1, [tsk, #TI_FLAGS]
+   ldr r2, [tsk, #TI_ADDR_LIMIT]
tst r1, #_TIF_WORK_MASK
bne slow_work_pending
 no_work_pending:
+   cmp r2, #TASK_SIZE
+   blneaddr_limit_fail
asm_trace_hardirqs_on save = 0
 
/* perform architecture specific actions before user return */
@@ -125,6 +133,12 @@ ENTRY(ret_from_fork)
b   ret_slow_syscall
 ENDPROC(ret_from_fork)
 
+addr_limit_fail:
+   stmfd   sp!, {r0, lr}
+   bl  asm_verify_pre_usermode_state
+   ldmfd   sp!, {r0, lr}
+   ret lr
+
 /*=
  * SWI handler
  *-
-- 
2.12.2.715.g7642488e1d-goog