mirror of
https://github.com/Fishwaldo/linux-bl808.git
synced 2025-06-17 20:25:19 +00:00
ebeb8c82ff
Extend ARCH_HAS_SYSCALL_WRAPPER for i386 emulation and for x32 on 64-bit
x86.
For x32, all we need to do is to create an additional stub for each
compat syscall which decodes the parameters in x86-64 ordering, e.g.:
asmlinkage long __compat_sys_x32_xyzzy(struct pt_regs *regs)
{
return c_SyS_xyzzy(regs->di, regs->si, regs->dx);
}
For i386 emulation, we need to teach compat_sys_*() to take struct
pt_regs as its only argument, e.g.:
asmlinkage long __compat_sys_ia32_xyzzy(struct pt_regs *regs)
{
return c_SyS_xyzzy(regs->bx, regs->cx, regs->dx);
}
In addition, we need to create additional stubs for common syscalls
(that is, for syscalls which have the same parameters on 32-bit and
64-bit), e.g.:
asmlinkage long __sys_ia32_xyzzy(struct pt_regs *regs)
{
return c_sys_xyzzy(regs->bx, regs->cx, regs->dx);
}
This approach avoids leaking random user-provided register content down
the call chain.
This patch is based on an original proof-of-concept
| From: Linus Torvalds <torvalds@linux-foundation.org>
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
and was split up and heavily modified by me, in particular to base it on
ARCH_HAS_SYSCALL_WRAPPER.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180405095307.3730-6-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
179 lines
6.6 KiB
C
179 lines
6.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* syscall_wrapper.h - x86 specific wrappers to syscall definitions
|
|
*/
|
|
|
|
#ifndef _ASM_X86_SYSCALL_WRAPPER_H
|
|
#define _ASM_X86_SYSCALL_WRAPPER_H
|
|
|
|
/* Mapping of registers to parameters for syscalls on x86-64 and x32 */
|
|
#define SC_X86_64_REGS_TO_ARGS(x, ...) \
|
|
__MAP(x,__SC_ARGS \
|
|
,,regs->di,,regs->si,,regs->dx \
|
|
,,regs->r10,,regs->r8,,regs->r9) \
|
|
|
|
/* Mapping of registers to parameters for syscalls on i386 */
|
|
#define SC_IA32_REGS_TO_ARGS(x, ...) \
|
|
__MAP(x,__SC_ARGS \
|
|
,,(unsigned int)regs->bx,,(unsigned int)regs->cx \
|
|
,,(unsigned int)regs->dx,,(unsigned int)regs->si \
|
|
,,(unsigned int)regs->di,,(unsigned int)regs->bp)
|
|
|
|
#ifdef CONFIG_IA32_EMULATION
|
|
/*
|
|
* For IA32 emulation, we need to handle "compat" syscalls *and* create
|
|
* additional wrappers (aptly named __sys_ia32_sys_xyzzy) which decode the
|
|
* ia32 regs in the proper order for shared or "common" syscalls. As some
|
|
* syscalls may not be implemented, we need to expand COND_SYSCALL in
|
|
* kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this
|
|
* case as well.
|
|
*/
|
|
#define COMPAT_SC_IA32_STUBx(x, name, ...) \
|
|
asmlinkage long __compat_sys_ia32##name(const struct pt_regs *regs);\
|
|
ALLOW_ERROR_INJECTION(__compat_sys_ia32##name, ERRNO); \
|
|
asmlinkage long __compat_sys_ia32##name(const struct pt_regs *regs)\
|
|
{ \
|
|
return c_SyS##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\
|
|
} \
|
|
|
|
#define SC_IA32_WRAPPERx(x, name, ...) \
|
|
asmlinkage long __sys_ia32##name(const struct pt_regs *regs); \
|
|
ALLOW_ERROR_INJECTION(__sys_ia32##name, ERRNO); \
|
|
asmlinkage long __sys_ia32##name(const struct pt_regs *regs) \
|
|
{ \
|
|
return SyS##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__)); \
|
|
}
|
|
|
|
#define COND_SYSCALL(name) \
|
|
cond_syscall(sys_##name); \
|
|
cond_syscall(__sys_ia32_##name)
|
|
|
|
#define SYS_NI(name) \
|
|
SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers); \
|
|
SYSCALL_ALIAS(__sys_ia32_##name, sys_ni_posix_timers)
|
|
|
|
#else /* CONFIG_IA32_EMULATION */
|
|
#define COMPAT_SC_IA32_STUBx(x, name, ...)
|
|
#define SC_IA32_WRAPPERx(x, fullname, name, ...)
|
|
#endif /* CONFIG_IA32_EMULATION */
|
|
|
|
|
|
#ifdef CONFIG_X86_X32
|
|
/*
|
|
* For the x32 ABI, we need to create a stub for compat_sys_*() which is aware
|
|
* of the x86-64-style parameter ordering of x32 syscalls. The syscalls common
|
|
* with x86_64 obviously do not need such care.
|
|
*/
|
|
#define COMPAT_SC_X32_STUBx(x, name, ...) \
|
|
asmlinkage long __compat_sys_x32##name(const struct pt_regs *regs);\
|
|
ALLOW_ERROR_INJECTION(__compat_sys_x32##name, ERRNO); \
|
|
asmlinkage long __compat_sys_x32##name(const struct pt_regs *regs)\
|
|
{ \
|
|
return c_SyS##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\
|
|
} \
|
|
|
|
#else /* CONFIG_X86_X32 */
|
|
#define COMPAT_SC_X32_STUBx(x, name, ...)
|
|
#endif /* CONFIG_X86_X32 */
|
|
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
/*
|
|
* Compat means IA32_EMULATION and/or X86_X32. As they use a different
|
|
* mapping of registers to parameters, we need to generate stubs for each
|
|
* of them. There is no need to implement COMPAT_SYSCALL_DEFINE0, as it is
|
|
* unused on x86.
|
|
*/
|
|
#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
|
|
static long c_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
|
|
static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
|
|
COMPAT_SC_IA32_STUBx(x, name, __VA_ARGS__) \
|
|
COMPAT_SC_X32_STUBx(x, name, __VA_ARGS__) \
|
|
static long c_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
|
|
{ \
|
|
return C_SYSC##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \
|
|
} \
|
|
static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__))
|
|
|
|
/*
|
|
* As some compat syscalls may not be implemented, we need to expand
|
|
* COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in
|
|
* kernel/time/posix-stubs.c to cover this case as well.
|
|
*/
|
|
#define COND_SYSCALL_COMPAT(name) \
|
|
cond_syscall(__compat_sys_ia32_##name); \
|
|
cond_syscall(__compat_sys_x32_##name)
|
|
|
|
#define COMPAT_SYS_NI(name) \
|
|
SYSCALL_ALIAS(__compat_sys_ia32_##name, sys_ni_posix_timers); \
|
|
SYSCALL_ALIAS(__compat_sys_x32_##name, sys_ni_posix_timers)
|
|
|
|
#endif /* CONFIG_COMPAT */
|
|
|
|
|
|
/*
|
|
* Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes
|
|
* struct pt_regs *regs as the only argument of the syscall stub named
|
|
* sys_*(). It decodes just the registers it needs and passes them on to
|
|
* the SyS_*() wrapper and then to the SYSC_*() function doing the actual job.
|
|
* These wrappers and functions are inlined, meaning that the assembly looks
|
|
* as follows (slightly re-ordered):
|
|
*
|
|
* <sys_recv>: <-- syscall with 4 parameters
|
|
* callq <__fentry__>
|
|
*
|
|
* mov 0x70(%rdi),%rdi <-- decode regs->di
|
|
* mov 0x68(%rdi),%rsi <-- decode regs->si
|
|
* mov 0x60(%rdi),%rdx <-- decode regs->dx
|
|
* mov 0x38(%rdi),%rcx <-- decode regs->r10
|
|
*
|
|
* xor %r9d,%r9d <-- clear %r9
|
|
* xor %r8d,%r8d <-- clear %r8
|
|
*
|
|
* callq __sys_recvfrom <-- do the actual work in __sys_recvfrom()
|
|
* which takes 6 arguments
|
|
*
|
|
* cltq <-- extend return value to 64-bit
|
|
* retq <-- return
|
|
*
|
|
* This approach avoids leaking random user-provided register content down
|
|
* the call chain.
|
|
*
|
|
* If IA32_EMULATION is enabled, this macro generates an additional wrapper
|
|
* named __sys_ia32_*() which decodes the struct pt_regs *regs according
|
|
* to the i386 calling convention (bx, cx, dx, si, di, bp).
|
|
*
|
|
* As the generic SYSCALL_DEFINE0() macro does not decode any parameters for
|
|
* obvious reasons, and passing struct pt_regs *regs to it in %rdi does not
|
|
* hurt, there is no need to override it, or to define it differently for
|
|
* IA32_EMULATION.
|
|
*/
|
|
#define __SYSCALL_DEFINEx(x, name, ...) \
|
|
asmlinkage long sys##name(const struct pt_regs *regs); \
|
|
ALLOW_ERROR_INJECTION(sys##name, ERRNO); \
|
|
static long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
|
|
static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
|
|
asmlinkage long sys##name(const struct pt_regs *regs) \
|
|
{ \
|
|
return SyS##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\
|
|
} \
|
|
SC_IA32_WRAPPERx(x, name, __VA_ARGS__) \
|
|
static long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
|
|
{ \
|
|
long ret = SYSC##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \
|
|
__MAP(x,__SC_TEST,__VA_ARGS__); \
|
|
__PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
|
|
return ret; \
|
|
} \
|
|
static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__))
|
|
|
|
/*
|
|
* For VSYSCALLS, we need to declare these three syscalls with the new
|
|
* pt_regs-based calling convention for in-kernel use.
|
|
*/
|
|
struct pt_regs;
|
|
asmlinkage long sys_getcpu(const struct pt_regs *regs); /* di,si,dx */
|
|
asmlinkage long sys_gettimeofday(const struct pt_regs *regs); /* di,si */
|
|
asmlinkage long sys_time(const struct pt_regs *regs); /* di */
|
|
|
|
#endif /* _ASM_X86_SYSCALL_WRAPPER_H */
|