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Message-ID: <20161121105443.249ddff8@gandalf.local.home>
Date: Mon, 21 Nov 2016 10:54:43 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: alexander.levin@...izon.com
Cc: "dvyukov@...gle.com" <dvyukov@...gle.com>,
"tglx@...utronix.de" <tglx@...utronix.de>,
"scientist@...com" <scientist@...com>,
"glider@...gle.com" <glider@...gle.com>,
"andreyknvl@...gle.com" <andreyknvl@...gle.com>,
"arnd@...db.de" <arnd@...db.de>,
"mathieu.desnoyers@...icios.com" <mathieu.desnoyers@...icios.com>,
"daniel.vetter@...ll.ch" <daniel.vetter@...ll.ch>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC 2/3] abi_spec: hooks into syscall to allow pre and post
checking
On Wed, 16 Nov 2016 17:37:01 +0000
alexander.levin@...izon.com wrote:
> This is a simple way to be able to verify syscall parameters before the
> call to the actual syscall, and also verify the return value after the
> call.
>
> Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
> ---
> include/linux/syscalls.h | 7 ++++++-
> kernel/Makefile | 2 ++
> kernel/abi_spec.c | 15 +++++++++++++++
> 3 files changed, 23 insertions(+), 1 deletion(-)
> create mode 100644 kernel/abi_spec.c
>
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 91a740f..6aa3228 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -79,6 +79,7 @@ union bpf_attr;
> #include <linux/quota.h>
> #include <linux/key.h>
> #include <trace/syscall.h>
> +#include <linux/abi_spec.h>
>
> /*
> * __MAP - apply a macro to syscall arguments
> @@ -192,13 +193,17 @@ extern struct trace_event_functions exit_syscall_print_funcs;
>
> #define __PROTECT(...) asmlinkage_protect(__VA_ARGS__)
> #define __SYSCALL_DEFINEx(x, name, ...) \
> + extern const struct syscall_spec syscall_spec##name; \
> asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
> __attribute__((alias(__stringify(SyS##name)))); \
> static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
> asmlinkage long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
> asmlinkage long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
> { \
> - long ret = SYSC##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \
> + long ret; \
> + abispec_check_pre(&syscall_spec##name, __MAP(x,__SC_CAST,__VA_ARGS__)); \
> + ret = SYSC##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \
> + abispec_check_post(&syscall_spec##name, ret, __MAP(x,__SC_CAST,__VA_ARGS__)); \
Do you want this for DEFINE0() too? Or does this not care about system
calls with no arguments?
-- Steve
> __MAP(x,__SC_TEST,__VA_ARGS__); \
> __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
> return ret; \
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