From: He Zhe <zhe.he@windriver.com>
To: oleg@redhat.com, linux-kernel@vger.kernel.org, zhe.he@windriver.com
Subject: [PATCH 2/2] ptrace: is_syscall_success: Add syscall return code handling for compat task
Date: Wed, 14 Apr 2021 16:02:45 +0800 [thread overview]
Message-ID: <20210414080245.25476-1-zhe.he@windriver.com> (raw)
When 32-bit userspace application is running on 64-bit kernel, the 32-bit
syscall return code would be changed from u32 to u64 in regs_return_value
and then changed to s64. Hence the negative return code would be treated
as a positive number and results in a non-error in, for example, audit
like below.
type=SYSCALL msg=audit(1611110715.887:582): arch=40000028 syscall=322
success=yes exit=4294967283
This patch forces the u32->s32->s64 for compat tasks.
Signed-off-by: He Zhe <zhe.he@windriver.com>
---
include/linux/ptrace.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index b5ebf6c01292..bc3056fff8a6 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -260,7 +260,9 @@ static inline void ptrace_release_task(struct task_struct *task)
* is an error value. On some systems like ia64 and powerpc they have different
* indicators of success/failure and must define their own.
*/
-#define is_syscall_success(regs) (!IS_ERR_VALUE((unsigned long)(regs_return_value(regs))))
+#define is_syscall_success(regs) (!IS_ERR_VALUE(is_compat_task() ? \
+ (unsigned long)(s64)(s32)(regs_return_value(regs)) : \
+ (unsigned long)(regs_return_value(regs))))
#endif
/*
--
2.17.1
next reply other threads:[~2021-04-14 8:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 8:02 He Zhe [this message]
2021-04-14 15:08 ` [PATCH 2/2] ptrace: is_syscall_success: Add syscall return code handling for compat task Oleg Nesterov
2021-04-14 16:17 ` David Laight
2021-04-14 16:55 ` Oleg Nesterov
2021-04-14 21:39 ` David Laight
2021-04-15 5:12 ` He Zhe
2021-04-15 5:48 ` Oleg Nesterov
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