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* [PATCH 1/3] arm64: ptrace: Add is_syscall_success to handle compat
@ 2021-04-16  7:55 He Zhe
  2021-04-16  7:55 ` [PATCH 2/3] arm64: syscall.h: Add sign extension handling in syscall_get_return_value for compat He Zhe
                   ` (2 more replies)
  0 siblings, 3 replies; 18+ messages in thread
From: He Zhe @ 2021-04-16  7:55 UTC (permalink / raw)
  To: oleg, catalin.marinas, will, linux-arm-kernel, paul, eparis,
	linux-audit, linux-kernel, zhe.he

The general version of is_syscall_success does not handle 32-bit
compatible case, which would cause 32-bit negative return code to be
recoganized as a positive number later and seen as a "success".

Since is_compat_thread is defined in compat.h, implementing
is_syscall_success in ptrace.h would introduce build failure due to
recursive inclusion of some basic headers like mutex.h. We put the
implementation to ptrace.c

Signed-off-by: He Zhe <zhe.he@windriver.com>
---
 arch/arm64/include/asm/ptrace.h |  3 +++
 arch/arm64/kernel/ptrace.c      | 10 ++++++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index e58bca832dff..3c415e9e5d85 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -328,6 +328,9 @@ static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
 	regs->regs[0] = rc;
 }
 
+extern inline int is_syscall_success(struct pt_regs *regs);
+#define is_syscall_success(regs) is_syscall_success(regs)
+
 /**
  * regs_get_kernel_argument() - get Nth function argument in kernel
  * @regs:	pt_regs of that context
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 170f42fd6101..3266201f8c60 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1909,3 +1909,13 @@ int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task)
 	else
 		return valid_native_regs(regs);
 }
+
+inline int is_syscall_success(struct pt_regs *regs)
+{
+	unsigned long val = regs->regs[0];
+
+	if (is_compat_thread(task_thread_info(current)))
+		val = sign_extend64(val, 31);
+
+	return !IS_ERR_VALUE(val);
+}
-- 
2.17.1

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^ permalink raw reply	[flat|nested] 18+ messages in thread

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Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-16  7:55 [PATCH 1/3] arm64: ptrace: Add is_syscall_success to handle compat He Zhe
2021-04-16  7:55 ` [PATCH 2/3] arm64: syscall.h: Add sign extension handling in syscall_get_return_value for compat He Zhe
2021-04-16  9:43   ` Oleg Nesterov
2021-04-20  8:38     ` He Zhe
2021-04-21 17:41   ` Mark Rutland
2021-04-22 16:55     ` Mark Rutland
2021-04-16  7:55 ` [PATCH 3/3] audit: Use syscall_get_return_value to get syscall return code in audit_syscall_exit He Zhe
2021-04-16 12:33 ` [PATCH 1/3] arm64: ptrace: Add is_syscall_success to handle compat Catalin Marinas
2021-04-16 13:34   ` Mark Rutland
2021-04-17 13:19     ` David Laight
2021-04-19 12:19     ` Will Deacon
2021-04-20  8:54       ` He Zhe
2021-04-21 17:10       ` Mark Rutland
2021-04-22 16:07         ` Will Deacon
2021-04-22 16:42           ` Mark Rutland
2021-04-22 18:57             ` Dmitry V. Levin
2021-04-20  8:42   ` He Zhe
2021-04-21 17:17     ` Mark Rutland

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