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Updates for miscellaneous x86 areas:

Browse Source 
- Reserve a new boot loader type for barebox which is usally used on ARM
     and MIPS, but can also be utilized as EFI payload on x86 to provide
     watchdog-supervised boot up.
 
   - Consolidate the native and compat 32bit signal handling code and split
     the 64bit version out into a separate source file
 
   - Switch the ESPFIX random usage to get_random_long().
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Merge tag 'x86-misc-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 updates from Thomas Gleixner:
 "Updates for miscellaneous x86 areas:

   - Reserve a new boot loader type for barebox which is usally used on
     ARM and MIPS, but can also be utilized as EFI payload on x86 to
     provide watchdog-supervised boot up.

   - Consolidate the native and compat 32bit signal handling code and
     split the 64bit version out into a separate source file

   - Switch the ESPFIX random usage to get_random_long()"

* tag 'x86-misc-2022-12-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/espfix: Use get_random_long() rather than archrandom
  x86/signal/64: Move 64-bit signal code to its own file
  x86/signal/32: Merge native and compat 32-bit signal code
  x86/signal: Add ABI prefixes to frame setup functions
  x86/signal: Merge get_sigframe()
  x86: Remove __USER32_DS
  signal/compat: Remove compat_sigset_t override
  x86/signal: Remove sigset_t parameter from frame setup functions
  x86/signal: Remove sig parameter from frame setup functions
  Documentation/x86/boot: Reserve type_of_loader=13 for barebox
This commit is contained in:
Linus Torvalds 2022-12-12 13:01:14 -08:00
commit 631aa74442
16 changed files with 497 additions and 723 deletions
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1
Documentation/x86/boot.rst
View File

@ -455,6 +455,7 @@ Protocol: 2.00+
11 Minimal Linux Bootloader
<http://sebastian-plotz.blogspot.de>
12 OVMF UEFI virtualization stack
13 barebox
== =======================================
Please contact <hpa@zytor.com> if you need a bootloader ID value assigned.

4
arch/x86/entry/entry_64_compat.S
View File

@ -61,7 +61,7 @@ SYM_CODE_START(entry_SYSENTER_compat)
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
/* Construct struct pt_regs on stack */
pushq $__USER32_DS /* pt_regs->ss */
pushq $__USER_DS /* pt_regs->ss */
pushq $0 /* pt_regs->sp = 0 (placeholder) */
/*
@ -197,7 +197,7 @@ SYM_INNER_LABEL(entry_SYSCALL_compat_safe_stack, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
/* Construct struct pt_regs on stack */
pushq $__USER32_DS /* pt_regs->ss */
pushq $__USER_DS /* pt_regs->ss */
pushq %r8 /* pt_regs->sp */
pushq %r11 /* pt_regs->flags */
pushq $__USER32_CS /* pt_regs->cs */

2
arch/x86/ia32/Makefile
View File

@ -3,7 +3,5 @@
# Makefile for the ia32 kernel emulation subsystem.
#
obj-$(CONFIG_IA32_EMULATION) := ia32_signal.o
audit-class-$(CONFIG_AUDIT) := audit.o
obj-$(CONFIG_IA32_EMULATION) += $(audit-class-y)

4
arch/x86/include/asm/elf.h
View File

@ -152,10 +152,6 @@ do { \
(elf_check_arch_ia32(x) || \
(IS_ENABLED(CONFIG_X86_X32_ABI) && (x)->e_machine == EM_X86_64))
#if __USER32_DS != __USER_DS
# error "The following code assumes __USER32_DS == __USER_DS"
#endif
static inline void elf_common_init(struct thread_struct *t,
struct pt_regs *regs, const u16 ds)
{

7
arch/x86/include/asm/fpu/signal.h
View File

@ -13,16 +13,9 @@
#ifdef CONFIG_X86_64
# include <uapi/asm/sigcontext.h>
# include <asm/user32.h>
struct ksignal;
int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
compat_sigset_t *set, struct pt_regs *regs);
int ia32_setup_frame(int sig, struct ksignal *ksig,
compat_sigset_t *set, struct pt_regs *regs);
#else
# define user_i387_ia32_struct user_i387_struct
# define user32_fxsr_struct user_fxsr_struct
# define ia32_setup_frame __setup_frame
# define ia32_setup_rt_frame __setup_rt_frame
#endif
extern void convert_from_fxsr(struct user_i387_ia32_struct *env,

2
arch/x86/include/asm/segment.h
View File

@ -135,6 +135,7 @@
#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
#define __USER32_CS __USER_CS
#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS*8)
/* segment for calling fn: */
@ -210,7 +211,6 @@
#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS*8)
#define __USER32_CS (GDT_ENTRY_DEFAULT_USER32_CS*8 + 3)
#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS*8 + 3)
#define __USER32_DS __USER_DS
#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS*8 + 3)
#define __CPUNODE_SEG (GDT_ENTRY_CPUNODE*8 + 3)

9
arch/x86/include/asm/sighandling.h
View File

@ -15,4 +15,13 @@
void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
void __user *
get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size,
void __user **fpstate);
int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs);
int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs);
int x64_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs);
int x32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs);
#endif /* _ASM_X86_SIGHANDLING_H */

5
arch/x86/include/asm/signal.h
View File

@ -28,11 +28,6 @@ typedef struct {
#define SA_IA32_ABI 0x02000000u
#define SA_X32_ABI 0x01000000u
#ifndef CONFIG_COMPAT
#define compat_sigset_t compat_sigset_t
typedef sigset_t compat_sigset_t;
#endif
#endif /* __ASSEMBLY__ */
#include <uapi/asm/signal.h>
#ifndef __ASSEMBLY__

4
arch/x86/kernel/Makefile
View File

@ -44,7 +44,7 @@ obj-y += head_$(BITS).o
obj-y += head$(BITS).o
obj-y += ebda.o
obj-y += platform-quirks.o
obj-y += process_$(BITS).o signal.o
obj-y += process_$(BITS).o signal.o signal_$(BITS).o
obj-$(CONFIG_COMPAT) += signal_compat.o
obj-y += traps.o idt.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
obj-y += time.o ioport.o dumpstack.o nmi.o
@ -54,7 +54,7 @@ obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_IRQ_WORK) += irq_work.o
obj-y += probe_roms.o
obj-$(CONFIG_X86_32) += sys_ia32.o
obj-$(CONFIG_IA32_EMULATION) += sys_ia32.o
obj-$(CONFIG_IA32_EMULATION) += sys_ia32.o signal_32.o
obj-$(CONFIG_X86_64) += sys_x86_64.o
obj-$(CONFIG_X86_ESPFIX64) += espfix_64.o
obj-$(CONFIG_SYSFS) += ksysfs.o

12
arch/x86/kernel/espfix_64.c
View File

@ -94,17 +94,7 @@ static inline unsigned long espfix_base_addr(unsigned int cpu)
static void init_espfix_random(void)
{
unsigned long rand;
/*
* This is run before the entropy pools are initialized,
* but this is hopefully better than nothing.
*/
if (!arch_get_random_longs(&rand, 1)) {
/* The constant is an arbitrary large prime */
rand = rdtsc();
rand *= 0xc345c6b72fd16123UL;
}
unsigned long rand = get_random_long();
slot_random = rand % ESPFIX_STACKS_PER_PAGE;
page_random = (rand / ESPFIX_STACKS_PER_PAGE)

658
arch/x86/kernel/signal.c
View File

@ -37,179 +37,26 @@
#include <asm/sighandling.h>
#include <asm/vm86.h>
#ifdef CONFIG_X86_64
#include <linux/compat.h>
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
#include <asm/fpu/xstate.h>
#endif /* CONFIG_X86_64 */
#include <asm/syscall.h>
#include <asm/sigframe.h>
#include <asm/signal.h>
#ifdef CONFIG_X86_64
/*
* If regs->ss will cause an IRET fault, change it. Otherwise leave it
* alone. Using this generally makes no sense unless
* user_64bit_mode(regs) would return true.
*/
static void force_valid_ss(struct pt_regs *regs)
static inline int is_ia32_compat_frame(struct ksignal *ksig)
{
u32 ar;
asm volatile ("lar %[old_ss], %[ar]\n\t"
"jz 1f\n\t" /* If invalid: */
"xorl %[ar], %[ar]\n\t" /* set ar = 0 */
"1:"
: [ar] "=r" (ar)
: [old_ss] "rm" ((u16)regs->ss));
/*
* For a valid 64-bit user context, we need DPL 3, type
* read-write data or read-write exp-down data, and S and P
* set. We can't use VERW because VERW doesn't check the
* P bit.
*/
ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK;
if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) &&
ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN))
regs->ss = __USER_DS;
}
# define CONTEXT_COPY_SIZE offsetof(struct sigcontext, reserved1)
#else
# define CONTEXT_COPY_SIZE sizeof(struct sigcontext)
#endif
static bool restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *usc,
unsigned long uc_flags)
{
struct sigcontext sc;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE))
return false;
#ifdef CONFIG_X86_32
loadsegment(gs, sc.gs);
regs->fs = sc.fs;
regs->es = sc.es;
regs->ds = sc.ds;
#endif /* CONFIG_X86_32 */
regs->bx = sc.bx;
regs->cx = sc.cx;
regs->dx = sc.dx;
regs->si = sc.si;
regs->di = sc.di;
regs->bp = sc.bp;
regs->ax = sc.ax;
regs->sp = sc.sp;
regs->ip = sc.ip;
#ifdef CONFIG_X86_64
regs->r8 = sc.r8;
regs->r9 = sc.r9;
regs->r10 = sc.r10;
regs->r11 = sc.r11;
regs->r12 = sc.r12;
regs->r13 = sc.r13;
regs->r14 = sc.r14;
regs->r15 = sc.r15;
#endif /* CONFIG_X86_64 */
/* Get CS/SS and force CPL3 */
regs->cs = sc.cs | 0x03;
regs->ss = sc.ss | 0x03;
regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS);
/* disable syscall checks */
regs->orig_ax = -1;
#ifdef CONFIG_X86_64
/*
* Fix up SS if needed for the benefit of old DOSEMU and
* CRIU.
*/
if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && user_64bit_mode(regs)))
force_valid_ss(regs);
#endif
return fpu__restore_sig((void __user *)sc.fpstate,
IS_ENABLED(CONFIG_X86_32));
return IS_ENABLED(CONFIG_IA32_EMULATION) &&
ksig->ka.sa.sa_flags & SA_IA32_ABI;
}
static __always_inline int
__unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
struct pt_regs *regs, unsigned long mask)
static inline int is_ia32_frame(struct ksignal *ksig)
{
#ifdef CONFIG_X86_32
unsigned int gs;
savesegment(gs, gs);
unsafe_put_user(gs, (unsigned int __user *)&sc->gs, Efault);
unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault);
unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault);
unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault);
#endif /* CONFIG_X86_32 */
unsafe_put_user(regs->di, &sc->di, Efault);
unsafe_put_user(regs->si, &sc->si, Efault);
unsafe_put_user(regs->bp, &sc->bp, Efault);
unsafe_put_user(regs->sp, &sc->sp, Efault);
unsafe_put_user(regs->bx, &sc->bx, Efault);
unsafe_put_user(regs->dx, &sc->dx, Efault);
unsafe_put_user(regs->cx, &sc->cx, Efault);
unsafe_put_user(regs->ax, &sc->ax, Efault);
#ifdef CONFIG_X86_64
unsafe_put_user(regs->r8, &sc->r8, Efault);
unsafe_put_user(regs->r9, &sc->r9, Efault);
unsafe_put_user(regs->r10, &sc->r10, Efault);
unsafe_put_user(regs->r11, &sc->r11, Efault);
unsafe_put_user(regs->r12, &sc->r12, Efault);
unsafe_put_user(regs->r13, &sc->r13, Efault);
unsafe_put_user(regs->r14, &sc->r14, Efault);
unsafe_put_user(regs->r15, &sc->r15, Efault);
#endif /* CONFIG_X86_64 */
unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault);
unsafe_put_user(current->thread.error_code, &sc->err, Efault);
unsafe_put_user(regs->ip, &sc->ip, Efault);
#ifdef CONFIG_X86_32
unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault);
unsafe_put_user(regs->flags, &sc->flags, Efault);
unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault);
unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault);
#else /* !CONFIG_X86_32 */
unsafe_put_user(regs->flags, &sc->flags, Efault);
unsafe_put_user(regs->cs, &sc->cs, Efault);
unsafe_put_user(0, &sc->gs, Efault);
unsafe_put_user(0, &sc->fs, Efault);
unsafe_put_user(regs->ss, &sc->ss, Efault);
#endif /* CONFIG_X86_32 */
unsafe_put_user(fpstate, (unsigned long __user *)&sc->fpstate, Efault);
/* non-iBCS2 extensions.. */
unsafe_put_user(mask, &sc->oldmask, Efault);
unsafe_put_user(current->thread.cr2, &sc->cr2, Efault);
return 0;
Efault:
return -EFAULT;
return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);
}
#define unsafe_put_sigcontext(sc, fp, regs, set, label) \
do { \
if (__unsafe_setup_sigcontext(sc, fp, regs, set->sig[0])) \
goto label; \
} while(0);
#define unsafe_put_sigmask(set, frame, label) \
unsafe_put_user(*(__u64 *)(set), \
(__u64 __user *)&(frame)->uc.uc_sigmask, \
label)
static inline int is_x32_frame(struct ksignal *ksig)
{
return IS_ENABLED(CONFIG_X86_X32_ABI) &&
ksig->ka.sa.sa_flags & SA_X32_ABI;
}
/*
* Set up a signal frame.
@ -223,24 +70,12 @@ do { \
/*
* Determine which stack to use..
*/
static unsigned long align_sigframe(unsigned long sp)
{
#ifdef CONFIG_X86_32
/*
* Align the stack pointer according to the i386 ABI,
* i.e. so that on function entry ((sp + 4) & 15) == 0.
*/
sp = ((sp + 4) & -FRAME_ALIGNMENT) - 4;
#else /* !CONFIG_X86_32 */
sp = round_down(sp, FRAME_ALIGNMENT) - 8;
#endif
return sp;
}
static void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
void __user *
get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size,
void __user **fpstate)
{
struct k_sigaction *ka = &ksig->ka;
int ia32_frame = is_ia32_frame(ksig);
/* Default to using normal stack */
bool nested_altstack = on_sig_stack(regs->sp);
bool entering_altstack = false;
@ -249,7 +84,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
unsigned long buf_fx = 0;
/* redzone */
if (IS_ENABLED(CONFIG_X86_64))
if (!ia32_frame)
sp -= 128;
/* This is the X/Open sanctioned signal stack switching. */
@ -263,7 +98,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
sp = current->sas_ss_sp + current->sas_ss_size;
entering_altstack = true;
}
} else if (IS_ENABLED(CONFIG_X86_32) &&
} else if (ia32_frame &&
!nested_altstack &&
regs->ss != __USER_DS &&
!(ka->sa.sa_flags & SA_RESTORER) &&
@ -273,11 +108,19 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
entering_altstack = true;
}
sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),
&buf_fx, &math_size);
sp = fpu__alloc_mathframe(sp, ia32_frame, &buf_fx, &math_size);
*fpstate = (void __user *)sp;
sp = align_sigframe(sp - frame_size);
sp -= frame_size;
if (ia32_frame)
/*
* Align the stack pointer according to the i386 ABI,
* i.e. so that on function entry ((sp + 4) & 15) == 0.
*/
sp = ((sp + 4) & -FRAME_ALIGNMENT) - 4;
else
sp = round_down(sp, FRAME_ALIGNMENT) - 8;
/*
* If we are on the alternate signal stack and would overflow it, don't.
@ -300,391 +143,6 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
return (void __user *)sp;
}
#ifdef CONFIG_X86_32
static const struct {
u16 poplmovl;
u32 val;
u16 int80;
} __attribute__((packed)) retcode = {
0xb858, /* popl %eax; movl $..., %eax */
__NR_sigreturn,
0x80cd, /* int $0x80 */
};
static const struct {
u8 movl;
u32 val;
u16 int80;
u8 pad;
} __attribute__((packed)) rt_retcode = {
0xb8, /* movl $..., %eax */
__NR_rt_sigreturn,
0x80cd, /* int $0x80 */
0
};
static int
__setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct sigframe __user *frame;
void __user *restorer;
void __user *fp = NULL;
frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
unsafe_put_user(sig, &frame->sig, Efault);
unsafe_put_sigcontext(&frame->sc, fp, regs, set, Efault);
unsafe_put_user(set->sig[1], &frame->extramask[0], Efault);
if (current->mm->context.vdso)
restorer = current->mm->context.vdso +
vdso_image_32.sym___kernel_sigreturn;
else
restorer = &frame->retcode;
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ksig->ka.sa.sa_restorer;
/* Set up to return from userspace. */
unsafe_put_user(restorer, &frame->pretcode, Efault);
/*
* This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
*
* WE DO NOT USE IT ANY MORE! It's only left here for historical
* reasons and because gdb uses it as a signature to notice
* signal handler stack frames.
*/
unsafe_put_user(*((u64 *)&retcode), (u64 *)frame->retcode, Efault);
user_access_end();
/* Set up registers for signal handler */
regs->sp = (unsigned long)frame;
regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
regs->ax = (unsigned long)sig;
regs->dx = 0;
regs->cx = 0;
regs->ds = __USER_DS;
regs->es = __USER_DS;
regs->ss = __USER_DS;
regs->cs = __USER_CS;
return 0;
Efault:
user_access_end();
return -EFAULT;
}
static int __setup_rt_frame(int sig, struct ksignal *ksig,
sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
void __user *restorer;
void __user *fp = NULL;
frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
unsafe_put_user(sig, &frame->sig, Efault);
unsafe_put_user(&frame->info, &frame->pinfo, Efault);
unsafe_put_user(&frame->uc, &frame->puc, Efault);
/* Create the ucontext. */
if (static_cpu_has(X86_FEATURE_XSAVE))
unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault);
else
unsafe_put_user(0, &frame->uc.uc_flags, Efault);
unsafe_put_user(0, &frame->uc.uc_link, Efault);
unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
/* Set up to return from userspace. */
restorer = current->mm->context.vdso +
vdso_image_32.sym___kernel_rt_sigreturn;
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ksig->ka.sa.sa_restorer;
unsafe_put_user(restorer, &frame->pretcode, Efault);
/*
* This is movl $__NR_rt_sigreturn, %ax ; int $0x80
*
* WE DO NOT USE IT ANY MORE! It's only left here for historical
* reasons and because gdb uses it as a signature to notice
* signal handler stack frames.
*/
unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault);
unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
unsafe_put_sigmask(set, frame, Efault);
user_access_end();
if (copy_siginfo_to_user(&frame->info, &ksig->info))
return -EFAULT;
/* Set up registers for signal handler */
regs->sp = (unsigned long)frame;
regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
regs->ax = (unsigned long)sig;
regs->dx = (unsigned long)&frame->info;
regs->cx = (unsigned long)&frame->uc;
regs->ds = __USER_DS;
regs->es = __USER_DS;
regs->ss = __USER_DS;
regs->cs = __USER_CS;
return 0;
Efault:
user_access_end();
return -EFAULT;
}
#else /* !CONFIG_X86_32 */
static unsigned long frame_uc_flags(struct pt_regs *regs)
{
unsigned long flags;
if (boot_cpu_has(X86_FEATURE_XSAVE))
flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS;
else
flags = UC_SIGCONTEXT_SS;
if (likely(user_64bit_mode(regs)))
flags |= UC_STRICT_RESTORE_SS;
return flags;
}
static int __setup_rt_frame(int sig, struct ksignal *ksig,
sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
void __user *fp = NULL;
unsigned long uc_flags;
/* x86-64 should always use SA_RESTORER. */
if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
return -EFAULT;
frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
uc_flags = frame_uc_flags(regs);
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
/* Create the ucontext. */
unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
unsafe_put_user(0, &frame->uc.uc_link, Efault);
unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault);
unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
unsafe_put_sigmask(set, frame, Efault);
user_access_end();
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
if (copy_siginfo_to_user(&frame->info, &ksig->info))
return -EFAULT;
}
/* Set up registers for signal handler */
regs->di = sig;
/* In case the signal handler was declared without prototypes */
regs->ax = 0;
/* This also works for non SA_SIGINFO handlers because they expect the
next argument after the signal number on the stack. */
regs->si = (unsigned long)&frame->info;
regs->dx = (unsigned long)&frame->uc;
regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
regs->sp = (unsigned long)frame;
/*
* Set up the CS and SS registers to run signal handlers in
* 64-bit mode, even if the handler happens to be interrupting
* 32-bit or 16-bit code.
*
* SS is subtle. In 64-bit mode, we don't need any particular
* SS descriptor, but we do need SS to be valid. It's possible
* that the old SS is entirely bogus -- this can happen if the
* signal we're trying to deliver is #GP or #SS caused by a bad
* SS value. We also have a compatibility issue here: DOSEMU
* relies on the contents of the SS register indicating the
* SS value at the time of the signal, even though that code in
* DOSEMU predates sigreturn's ability to restore SS. (DOSEMU
* avoids relying on sigreturn to restore SS; instead it uses
* a trampoline.) So we do our best: if the old SS was valid,
* we keep it. Otherwise we replace it.
*/
regs->cs = __USER_CS;
if (unlikely(regs->ss != __USER_DS))
force_valid_ss(regs);
return 0;
Efault:
user_access_end();
return -EFAULT;
}
#endif /* CONFIG_X86_32 */
#ifdef CONFIG_X86_X32_ABI
static int x32_copy_siginfo_to_user(struct compat_siginfo __user *to,
const struct kernel_siginfo *from)
{
struct compat_siginfo new;
copy_siginfo_to_external32(&new, from);
if (from->si_signo == SIGCHLD) {
new._sifields._sigchld_x32._utime = from->si_utime;
new._sifields._sigchld_x32._stime = from->si_stime;
}
if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
return -EFAULT;
return 0;
}
int copy_siginfo_to_user32(struct compat_siginfo __user *to,
const struct kernel_siginfo *from)
{
if (in_x32_syscall())
return x32_copy_siginfo_to_user(to, from);
return __copy_siginfo_to_user32(to, from);
}
#endif /* CONFIG_X86_X32_ABI */
static int x32_setup_rt_frame(struct ksignal *ksig,
compat_sigset_t *set,
struct pt_regs *regs)
{
#ifdef CONFIG_X86_X32_ABI
struct rt_sigframe_x32 __user *frame;
unsigned long uc_flags;
void __user *restorer;
void __user *fp = NULL;
if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
return -EFAULT;
frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
uc_flags = frame_uc_flags(regs);
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
/* Create the ucontext. */
unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
unsafe_put_user(0, &frame->uc.uc_link, Efault);
unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
unsafe_put_user(0, &frame->uc.uc__pad0, Efault);
restorer = ksig->ka.sa.sa_restorer;
unsafe_put_user(restorer, (unsigned long __user *)&frame->pretcode, Efault);
unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
unsafe_put_sigmask(set, frame, Efault);
user_access_end();
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
if (x32_copy_siginfo_to_user(&frame->info, &ksig->info))
return -EFAULT;
}
/* Set up registers for signal handler */
regs->sp = (unsigned long) frame;
regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
/* We use the x32 calling convention here... */
regs->di = ksig->sig;
regs->si = (unsigned long) &frame->info;
regs->dx = (unsigned long) &frame->uc;
loadsegment(ds, __USER_DS);
loadsegment(es, __USER_DS);
regs->cs = __USER_CS;
regs->ss = __USER_DS;
#endif /* CONFIG_X86_X32_ABI */
return 0;
#ifdef CONFIG_X86_X32_ABI
Efault:
user_access_end();
return -EFAULT;
#endif
}
/*
* Do a signal return; undo the signal stack.
*/
#ifdef CONFIG_X86_32
SYSCALL_DEFINE0(sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct sigframe __user *frame;
sigset_t set;
frame = (struct sigframe __user *)(regs->sp - 8);
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], &frame->sc.oldmask) ||
__get_user(set.sig[1], &frame->extramask[0]))
goto badframe;
set_current_blocked(&set);
/*
* x86_32 has no uc_flags bits relevant to restore_sigcontext.
* Save a few cycles by skipping the __get_user.
*/
if (!restore_sigcontext(regs, &frame->sc, 0))
goto badframe;
return regs->ax;
badframe:
signal_fault(regs, frame, "sigreturn");
return 0;
}
#endif /* CONFIG_X86_32 */
SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe __user *frame;
sigset_t set;
unsigned long uc_flags;
frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask))
goto badframe;
if (__get_user(uc_flags, &frame->uc.uc_flags))
goto badframe;
set_current_blocked(&set);
if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return regs->ax;
badframe:
signal_fault(regs, frame, "rt_sigreturn");
return 0;
}
/*
* There are four different struct types for signal frame: sigframe_ia32,
* rt_sigframe_ia32, rt_sigframe_x32, and rt_sigframe. Use the worst case
@ -743,43 +201,22 @@ unsigned long get_sigframe_size(void)
return max_frame_size;
}
static inline int is_ia32_compat_frame(struct ksignal *ksig)
{
return IS_ENABLED(CONFIG_IA32_EMULATION) &&
ksig->ka.sa.sa_flags & SA_IA32_ABI;
}
static inline int is_ia32_frame(struct ksignal *ksig)
{
return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);
}
static inline int is_x32_frame(struct ksignal *ksig)
{
return IS_ENABLED(CONFIG_X86_X32_ABI) &&
ksig->ka.sa.sa_flags & SA_X32_ABI;
}
static int
setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
{
int usig = ksig->sig;
sigset_t *set = sigmask_to_save();
compat_sigset_t *cset = (compat_sigset_t *) set;
/* Perform fixup for the pre-signal frame. */
rseq_signal_deliver(ksig, regs);
/* Set up the stack frame */
if (is_ia32_frame(ksig)) {
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
return ia32_setup_rt_frame(usig, ksig, cset, regs);
return ia32_setup_rt_frame(ksig, regs);
else
return ia32_setup_frame(usig, ksig, cset, regs);
return ia32_setup_frame(ksig, regs);
} else if (is_x32_frame(ksig)) {
return x32_setup_rt_frame(ksig, cset, regs);
return x32_setup_rt_frame(ksig, regs);
} else {
return __setup_rt_frame(ksig->sig, ksig, set, regs);
return x64_setup_rt_frame(ksig, regs);
}
}
@ -969,36 +406,3 @@ bool sigaltstack_size_valid(size_t ss_size)
return true;
}
#endif /* CONFIG_DYNAMIC_SIGFRAME */
#ifdef CONFIG_X86_X32_ABI
COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe_x32 __user *frame;
sigset_t set;
unsigned long uc_flags;
frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
goto badframe;
if (__get_user(uc_flags, &frame->uc.uc_flags))
goto badframe;
set_current_blocked(&set);
if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
goto badframe;
if (compat_restore_altstack(&frame->uc.uc_stack))
goto badframe;
return regs->ax;
badframe:
signal_fault(regs, frame, "x32 rt_sigreturn");
return 0;
}
#endif

117
arch/x86/ia32/ia32_signal.c → arch/x86/kernel/signal_32.c
View File

@ -1,7 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
/*
* linux/arch/x86_64/ia32/ia32_signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
@ -26,7 +24,6 @@
#include <linux/uaccess.h>
#include <asm/fpu/signal.h>
#include <asm/ptrace.h>
#include <asm/ia32_unistd.h>
#include <asm/user32.h>
#include <uapi/asm/sigcontext.h>
#include <asm/proto.h>
@ -35,6 +32,9 @@
#include <asm/sighandling.h>
#include <asm/smap.h>
#ifdef CONFIG_IA32_EMULATION
#include <asm/ia32_unistd.h>
static inline void reload_segments(struct sigcontext_32 *sc)
{
unsigned int cur;
@ -53,6 +53,21 @@ static inline void reload_segments(struct sigcontext_32 *sc)
loadsegment(es, sc->es | 0x03);
}
#define sigset32_t compat_sigset_t
#define restore_altstack32 compat_restore_altstack
#define unsafe_save_altstack32 unsafe_compat_save_altstack
#else
#define sigset32_t sigset_t
#define __NR_ia32_sigreturn __NR_sigreturn
#define __NR_ia32_rt_sigreturn __NR_rt_sigreturn
#define restore_altstack32 restore_altstack
#define unsafe_save_altstack32 unsafe_save_altstack
#define __copy_siginfo_to_user32 copy_siginfo_to_user
#endif
/*
* Do a signal return; undo the signal stack.
*/
@ -86,6 +101,7 @@ static bool ia32_restore_sigcontext(struct pt_regs *regs,
/* disable syscall checks */
regs->orig_ax = -1;
#ifdef CONFIG_IA32_EMULATION
/*
* Reload fs and gs if they have changed in the signal
* handler. This does not handle long fs/gs base changes in
@ -93,10 +109,17 @@ static bool ia32_restore_sigcontext(struct pt_regs *regs,
* normal case.
*/
reload_segments(&sc);
#else
loadsegment(gs, sc.gs);
regs->fs = sc.fs;
regs->es = sc.es;
regs->ds = sc.ds;
#endif
return fpu__restore_sig(compat_ptr(sc.fpstate), 1);
}
COMPAT_SYSCALL_DEFINE0(sigreturn)
SYSCALL32_DEFINE0(sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8);
@ -119,7 +142,7 @@ badframe:
return 0;
}
COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
SYSCALL32_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe_ia32 __user *frame;
@ -129,7 +152,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask))
goto badframe;
set_current_blocked(&set);
@ -137,7 +160,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
if (compat_restore_altstack(&frame->uc.uc_stack))
if (restore_altstack32(&frame->uc.uc_stack))
goto badframe;
return regs->ax;
@ -159,9 +182,15 @@ __unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc,
struct pt_regs *regs, unsigned int mask)
{
unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault);
#ifdef CONFIG_IA32_EMULATION
unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault);
unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault);
unsafe_put_user(get_user_seg(es), (unsigned int __user *)&sc->es, Efault);
#else
unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault);
unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault);
unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault);
#endif
unsafe_put_user(regs->di, &sc->di, Efault);
unsafe_put_user(regs->si, &sc->si, Efault);
@ -196,43 +225,9 @@ do { \
goto label; \
} while(0)
/*
* Determine which stack to use..
*/
static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
size_t frame_size,
void __user **fpstate)
{
unsigned long sp, fx_aligned, math_size;
/* Default to using normal stack */
sp = regs->sp;
/* This is the X/Open sanctioned signal stack switching. */
if (ksig->ka.sa.sa_flags & SA_ONSTACK)
sp = sigsp(sp, ksig);
/* This is the legacy signal stack switching. */
else if (regs->ss != __USER32_DS &&
!(ksig->ka.sa.sa_flags & SA_RESTORER) &&
ksig->ka.sa.sa_restorer)
sp = (unsigned long) ksig->ka.sa.sa_restorer;
sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
*fpstate = (struct _fpstate_32 __user *) sp;
if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
math_size))
return (void __user *) -1L;
sp -= frame_size;
/* Align the stack pointer according to the i386 ABI,
* i.e. so that on function entry ((sp + 4) & 15) == 0. */
sp = ((sp + 4) & -16ul) - 4;
return (void __user *) sp;
}
int ia32_setup_frame(int sig, struct ksignal *ksig,
compat_sigset_t *set, struct pt_regs *regs)
int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs)
{
sigset32_t *set = (sigset32_t *) sigmask_to_save();
struct sigframe_ia32 __user *frame;
void __user *restorer;
void __user *fp = NULL;
@ -264,7 +259,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
unsafe_put_user(sig, &frame->sig, Efault);
unsafe_put_user(ksig->sig, &frame->sig, Efault);
unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault);
unsafe_put_user(set->sig[1], &frame->extramask[0], Efault);
unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault);
@ -280,15 +275,20 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
/* Make -mregparm=3 work */
regs->ax = sig;
regs->ax = ksig->sig;
regs->dx = 0;
regs->cx = 0;
loadsegment(ds, __USER32_DS);
loadsegment(es, __USER32_DS);
#ifdef CONFIG_IA32_EMULATION
loadsegment(ds, __USER_DS);
loadsegment(es, __USER_DS);
#else
regs->ds = __USER_DS;
regs->es = __USER_DS;
#endif
regs->cs = __USER32_CS;
regs->ss = __USER32_DS;
regs->ss = __USER_DS;
return 0;
Efault:
@ -296,9 +296,9 @@ Efault:
return -EFAULT;
}
int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
compat_sigset_t *set, struct pt_regs *regs)
int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
{
sigset32_t *set = (sigset32_t *) sigmask_to_save();
struct rt_sigframe_ia32 __user *frame;
void __user *restorer;
void __user *fp = NULL;
@ -321,7 +321,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
unsafe_put_user(sig, &frame->sig, Efault);
unsafe_put_user(ksig->sig, &frame->sig, Efault);
unsafe_put_user(ptr_to_compat(&frame->info), &frame->pinfo, Efault);
unsafe_put_user(ptr_to_compat(&frame->uc), &frame->puc, Efault);
@ -331,7 +331,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
else
unsafe_put_user(0, &frame->uc.uc_flags, Efault);
unsafe_put_user(0, &frame->uc.uc_link, Efault);
unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
unsafe_save_altstack32(&frame->uc.uc_stack, regs->sp, Efault);
if (ksig->ka.sa.sa_flags & SA_RESTORER)
restorer = ksig->ka.sa.sa_restorer;
@ -357,15 +357,20 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
/* Make -mregparm=3 work */
regs->ax = sig;
regs->ax = ksig->sig;
regs->dx = (unsigned long) &frame->info;
regs->cx = (unsigned long) &frame->uc;
loadsegment(ds, __USER32_DS);
loadsegment(es, __USER32_DS);
#ifdef CONFIG_IA32_EMULATION
loadsegment(ds, __USER_DS);
loadsegment(es, __USER_DS);
#else
regs->ds = __USER_DS;
regs->es = __USER_DS;
#endif
regs->cs = __USER32_CS;
regs->ss = __USER32_DS;
regs->ss = __USER_DS;
return 0;
Efault:

383
arch/x86/kernel/signal_64.c Normal file
View File

@ -0,0 +1,383 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <asm/ucontext.h>
#include <asm/fpu/signal.h>
#include <asm/sighandling.h>
#include <asm/syscall.h>
#include <asm/sigframe.h>
#include <asm/signal.h>
/*
* If regs->ss will cause an IRET fault, change it. Otherwise leave it
* alone. Using this generally makes no sense unless
* user_64bit_mode(regs) would return true.
*/
static void force_valid_ss(struct pt_regs *regs)
{
u32 ar;
asm volatile ("lar %[old_ss], %[ar]\n\t"
"jz 1f\n\t" /* If invalid: */
"xorl %[ar], %[ar]\n\t" /* set ar = 0 */
"1:"
: [ar] "=r" (ar)
: [old_ss] "rm" ((u16)regs->ss));
/*
* For a valid 64-bit user context, we need DPL 3, type
* read-write data or read-write exp-down data, and S and P
* set. We can't use VERW because VERW doesn't check the
* P bit.
*/
ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK;
if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) &&
ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN))
regs->ss = __USER_DS;
}
static bool restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *usc,
unsigned long uc_flags)
{
struct sigcontext sc;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
if (copy_from_user(&sc, usc, offsetof(struct sigcontext, reserved1)))
return false;
regs->bx = sc.bx;
regs->cx = sc.cx;
regs->dx = sc.dx;
regs->si = sc.si;
regs->di = sc.di;
regs->bp = sc.bp;
regs->ax = sc.ax;
regs->sp = sc.sp;
regs->ip = sc.ip;
regs->r8 = sc.r8;
regs->r9 = sc.r9;
regs->r10 = sc.r10;
regs->r11 = sc.r11;
regs->r12 = sc.r12;
regs->r13 = sc.r13;
regs->r14 = sc.r14;
regs->r15 = sc.r15;
/* Get CS/SS and force CPL3 */
regs->cs = sc.cs | 0x03;
regs->ss = sc.ss | 0x03;
regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS);
/* disable syscall checks */
regs->orig_ax = -1;
/*
* Fix up SS if needed for the benefit of old DOSEMU and
* CRIU.
*/
if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && user_64bit_mode(regs)))
force_valid_ss(regs);
return fpu__restore_sig((void __user *)sc.fpstate, 0);
}
static __always_inline int
__unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
struct pt_regs *regs, unsigned long mask)
{
unsafe_put_user(regs->di, &sc->di, Efault);
unsafe_put_user(regs->si, &sc->si, Efault);
unsafe_put_user(regs->bp, &sc->bp, Efault);
unsafe_put_user(regs->sp, &sc->sp, Efault);
unsafe_put_user(regs->bx, &sc->bx, Efault);
unsafe_put_user(regs->dx, &sc->dx, Efault);
unsafe_put_user(regs->cx, &sc->cx, Efault);
unsafe_put_user(regs->ax, &sc->ax, Efault);
unsafe_put_user(regs->r8, &sc->r8, Efault);
unsafe_put_user(regs->r9, &sc->r9, Efault);
unsafe_put_user(regs->r10, &sc->r10, Efault);
unsafe_put_user(regs->r11, &sc->r11, Efault);
unsafe_put_user(regs->r12, &sc->r12, Efault);
unsafe_put_user(regs->r13, &sc->r13, Efault);
unsafe_put_user(regs->r14, &sc->r14, Efault);
unsafe_put_user(regs->r15, &sc->r15, Efault);
unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault);
unsafe_put_user(current->thread.error_code, &sc->err, Efault);
unsafe_put_user(regs->ip, &sc->ip, Efault);
unsafe_put_user(regs->flags, &sc->flags, Efault);
unsafe_put_user(regs->cs, &sc->cs, Efault);
unsafe_put_user(0, &sc->gs, Efault);
unsafe_put_user(0, &sc->fs, Efault);
unsafe_put_user(regs->ss, &sc->ss, Efault);
unsafe_put_user(fpstate, (unsigned long __user *)&sc->fpstate, Efault);
/* non-iBCS2 extensions.. */
unsafe_put_user(mask, &sc->oldmask, Efault);
unsafe_put_user(current->thread.cr2, &sc->cr2, Efault);
return 0;
Efault:
return -EFAULT;
}
#define unsafe_put_sigcontext(sc, fp, regs, set, label) \
do { \
if (__unsafe_setup_sigcontext(sc, fp, regs, set->sig[0])) \
goto label; \
} while(0);
#define unsafe_put_sigmask(set, frame, label) \
unsafe_put_user(*(__u64 *)(set), \
(__u64 __user *)&(frame)->uc.uc_sigmask, \
label)
static unsigned long frame_uc_flags(struct pt_regs *regs)
{
unsigned long flags;
if (boot_cpu_has(X86_FEATURE_XSAVE))
flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS;
else
flags = UC_SIGCONTEXT_SS;
if (likely(user_64bit_mode(regs)))
flags |= UC_STRICT_RESTORE_SS;
return flags;
}
int x64_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
{
sigset_t *set = sigmask_to_save();
struct rt_sigframe __user *frame;
void __user *fp = NULL;
unsigned long uc_flags;
/* x86-64 should always use SA_RESTORER. */
if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
return -EFAULT;
frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe), &fp);
uc_flags = frame_uc_flags(regs);
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
/* Create the ucontext. */
unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
unsafe_put_user(0, &frame->uc.uc_link, Efault);
unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault);
unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
unsafe_put_sigmask(set, frame, Efault);
user_access_end();
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
if (copy_siginfo_to_user(&frame->info, &ksig->info))
return -EFAULT;
}
/* Set up registers for signal handler */
regs->di = ksig->sig;
/* In case the signal handler was declared without prototypes */
regs->ax = 0;
/* This also works for non SA_SIGINFO handlers because they expect the
next argument after the signal number on the stack. */
regs->si = (unsigned long)&frame->info;
regs->dx = (unsigned long)&frame->uc;
regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
regs->sp = (unsigned long)frame;
/*
* Set up the CS and SS registers to run signal handlers in
* 64-bit mode, even if the handler happens to be interrupting
* 32-bit or 16-bit code.
*
* SS is subtle. In 64-bit mode, we don't need any particular
* SS descriptor, but we do need SS to be valid. It's possible
* that the old SS is entirely bogus -- this can happen if the
* signal we're trying to deliver is #GP or #SS caused by a bad
* SS value. We also have a compatibility issue here: DOSEMU
* relies on the contents of the SS register indicating the
* SS value at the time of the signal, even though that code in
* DOSEMU predates sigreturn's ability to restore SS. (DOSEMU
* avoids relying on sigreturn to restore SS; instead it uses
* a trampoline.) So we do our best: if the old SS was valid,
* we keep it. Otherwise we replace it.
*/
regs->cs = __USER_CS;
if (unlikely(regs->ss != __USER_DS))
force_valid_ss(regs);
return 0;
Efault:
user_access_end();
return -EFAULT;
}
/*
* Do a signal return; undo the signal stack.
*/
SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe __user *frame;
sigset_t set;
unsigned long uc_flags;
frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask))
goto badframe;
if (__get_user(uc_flags, &frame->uc.uc_flags))
goto badframe;
set_current_blocked(&set);
if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return regs->ax;
badframe:
signal_fault(regs, frame, "rt_sigreturn");
return 0;
}
#ifdef CONFIG_X86_X32_ABI
static int x32_copy_siginfo_to_user(struct compat_siginfo __user *to,
const struct kernel_siginfo *from)
{
struct compat_siginfo new;
copy_siginfo_to_external32(&new, from);
if (from->si_signo == SIGCHLD) {
new._sifields._sigchld_x32._utime = from->si_utime;
new._sifields._sigchld_x32._stime = from->si_stime;
}
if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
return -EFAULT;
return 0;
}
int copy_siginfo_to_user32(struct compat_siginfo __user *to,
const struct kernel_siginfo *from)
{
if (in_x32_syscall())
return x32_copy_siginfo_to_user(to, from);
return __copy_siginfo_to_user32(to, from);
}
int x32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
{
compat_sigset_t *set = (compat_sigset_t *) sigmask_to_save();
struct rt_sigframe_x32 __user *frame;
unsigned long uc_flags;
void __user *restorer;
void __user *fp = NULL;
if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
return -EFAULT;
frame = get_sigframe(ksig, regs, sizeof(*frame), &fp);
uc_flags = frame_uc_flags(regs);
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
/* Create the ucontext. */
unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
unsafe_put_user(0, &frame->uc.uc_link, Efault);
unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
unsafe_put_user(0, &frame->uc.uc__pad0, Efault);
restorer = ksig->ka.sa.sa_restorer;
unsafe_put_user(restorer, (unsigned long __user *)&frame->pretcode, Efault);
unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
unsafe_put_sigmask(set, frame, Efault);
user_access_end();
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
if (x32_copy_siginfo_to_user(&frame->info, &ksig->info))
return -EFAULT;
}
/* Set up registers for signal handler */
regs->sp = (unsigned long) frame;
regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
/* We use the x32 calling convention here... */
regs->di = ksig->sig;
regs->si = (unsigned long) &frame->info;
regs->dx = (unsigned long) &frame->uc;
loadsegment(ds, __USER_DS);
loadsegment(es, __USER_DS);
regs->cs = __USER_CS;
regs->ss = __USER_DS;
return 0;
Efault:
user_access_end();
return -EFAULT;
}
COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe_x32 __user *frame;
sigset_t set;
unsigned long uc_flags;
frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
goto badframe;
if (__get_user(uc_flags, &frame->uc.uc_flags))
goto badframe;
set_current_blocked(&set);
if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
goto badframe;
if (compat_restore_altstack(&frame->uc.uc_stack))
goto badframe;
return regs->ax;
badframe:
signal_fault(regs, frame, "x32 rt_sigreturn");
return 0;
}
#endif /* CONFIG_X86_X32_ABI */

8
arch/x86/xen/xen-asm.S
View File

@ -262,10 +262,10 @@ SYM_CODE_START(xen_entry_SYSCALL_compat)
/*
* Neither Xen nor the kernel really knows what the old SS and
* CS were. The kernel expects __USER32_DS and __USER32_CS, so
* CS were. The kernel expects __USER_DS and __USER32_CS, so
* report those values even though Xen will guess its own values.
*/
movq $__USER32_DS, 4*8(%rsp)
movq $__USER_DS, 4*8(%rsp)
movq $__USER32_CS, 1*8(%rsp)
jmp entry_SYSCALL_compat_after_hwframe
@ -284,10 +284,10 @@ SYM_CODE_START(xen_entry_SYSENTER_compat)
/*
* Neither Xen nor the kernel really knows what the old SS and
* CS were. The kernel expects __USER32_DS and __USER32_CS, so
* CS were. The kernel expects __USER_DS and __USER32_CS, so
* report those values even though Xen will guess its own values.
*/
movq $__USER32_DS, 4*8(%rsp)
movq $__USER_DS, 4*8(%rsp)
movq $__USER32_CS, 1*8(%rsp)
jmp entry_SYSENTER_compat_after_hwframe

2
include/linux/compat.h
View File

@ -126,11 +126,9 @@ struct compat_tms {
#define _COMPAT_NSIG_WORDS (_COMPAT_NSIG / _COMPAT_NSIG_BPW)
#ifndef compat_sigset_t
typedef struct {
compat_sigset_word sig[_COMPAT_NSIG_WORDS];
} compat_sigset_t;
#endif
int set_compat_user_sigmask(const compat_sigset_t __user *umask,
size_t sigsetsize);

2
include/linux/syscalls.h
View File

@ -264,6 +264,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
#define SC_VAL64(type, name) ((type) name##_hi << 32 | name##_lo)
#ifdef CONFIG_COMPAT
#define SYSCALL32_DEFINE0 COMPAT_SYSCALL_DEFINE0
#define SYSCALL32_DEFINE1 COMPAT_SYSCALL_DEFINE1
#define SYSCALL32_DEFINE2 COMPAT_SYSCALL_DEFINE2
#define SYSCALL32_DEFINE3 COMPAT_SYSCALL_DEFINE3
@ -271,6 +272,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
#define SYSCALL32_DEFINE5 COMPAT_SYSCALL_DEFINE5
#define SYSCALL32_DEFINE6 COMPAT_SYSCALL_DEFINE6
#else
#define SYSCALL32_DEFINE0 SYSCALL_DEFINE0
#define SYSCALL32_DEFINE1 SYSCALL_DEFINE1
#define SYSCALL32_DEFINE2 SYSCALL_DEFINE2
#define SYSCALL32_DEFINE3 SYSCALL_DEFINE3