diff options
| -rw-r--r-- | arch/x86/kernel/ptrace.c | 46 |
1 files changed, 38 insertions, 8 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index bedca011459c..87a4143aa7d7 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -704,6 +704,9 @@ void ptrace_disable(struct task_struct *child) #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION static const struct user_regset_view user_x86_32_view; /* Initialized below. */ #endif +#ifdef CONFIG_X86_64 +static const struct user_regset_view user_x86_64_view; /* Initialized below. */ +#endif long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data) @@ -711,6 +714,14 @@ long arch_ptrace(struct task_struct *child, long request, int ret; unsigned long __user *datap = (unsigned long __user *)data; +#ifdef CONFIG_X86_64 + /* This is native 64-bit ptrace() */ + const struct user_regset_view *regset_view = &user_x86_64_view; +#else + /* This is native 32-bit ptrace() */ + const struct user_regset_view *regset_view = &user_x86_32_view; +#endif + switch (request) { /* read the word at location addr in the USER area. */ case PTRACE_PEEKUSR: { @@ -749,28 +760,28 @@ long arch_ptrace(struct task_struct *child, long request, case PTRACE_GETREGS: /* Get all gp regs from the child. */ return copy_regset_to_user(child, - task_user_regset_view(current), + regset_view, REGSET_GENERAL, 0, sizeof(struct user_regs_struct), datap); case PTRACE_SETREGS: /* Set all gp regs in the child. */ return copy_regset_from_user(child, - task_user_regset_view(current), + regset_view, REGSET_GENERAL, 0, sizeof(struct user_regs_struct), datap); case PTRACE_GETFPREGS: /* Get the child FPU state. */ return copy_regset_to_user(child, - task_user_regset_view(current), + regset_view, REGSET_FP, 0, sizeof(struct user_i387_struct), datap); case PTRACE_SETFPREGS: /* Set the child FPU state. */ return copy_regset_from_user(child, - task_user_regset_view(current), + regset_view, REGSET_FP, 0, sizeof(struct user_i387_struct), datap); @@ -1152,28 +1163,28 @@ static long x32_arch_ptrace(struct task_struct *child, case PTRACE_GETREGS: /* Get all gp regs from the child. */ return copy_regset_to_user(child, - task_user_regset_view(current), + &user_x86_64_view, REGSET_GENERAL, 0, sizeof(struct user_regs_struct), datap); case PTRACE_SETREGS: /* Set all gp regs in the child. */ return copy_regset_from_user(child, - task_user_regset_view(current), + &user_x86_64_view, REGSET_GENERAL, 0, sizeof(struct user_regs_struct), datap); case PTRACE_GETFPREGS: /* Get the child FPU state. */ return copy_regset_to_user(child, - task_user_regset_view(current), + &user_x86_64_view, REGSET_FP, 0, sizeof(struct user_i387_struct), datap); case PTRACE_SETFPREGS: /* Set the child FPU state. */ return copy_regset_from_user(child, - task_user_regset_view(current), + &user_x86_64_view, REGSET_FP, 0, sizeof(struct user_i387_struct), datap); @@ -1309,6 +1320,25 @@ void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask) xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask; } +/* + * This is used by the core dump code to decide which regset to dump. The + * core dump code writes out the resulting .e_machine and the corresponding + * regsets. This is suboptimal if the task is messing around with its CS.L + * field, but at worst the core dump will end up missing some information. + * + * Unfortunately, it is also used by the broken PTRACE_GETREGSET and + * PTRACE_SETREGSET APIs. These APIs look at the .regsets field but have + * no way to make sure that the e_machine they use matches the caller's + * expectations. The result is that the data format returned by + * PTRACE_GETREGSET depends on the returned CS field (and even the offset + * of the returned CS field depends on its value!) and the data format + * accepted by PTRACE_SETREGSET is determined by the old CS value. The + * upshot is that it is basically impossible to use these APIs correctly. + * + * The best way to fix it in the long run would probably be to add new + * improved ptrace() APIs to read and write registers reliably, possibly by + * allowing userspace to select the ELF e_machine variant that they expect. + */ const struct user_regset_view *task_user_regset_view(struct task_struct *task) { #ifdef CONFIG_IA32_EMULATION |