diff options
Diffstat (limited to 'arch/i386/kernel/ptrace.c')
-rw-r--r-- | arch/i386/kernel/ptrace.c | 79 |
1 files changed, 66 insertions, 13 deletions
diff --git a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c index 0da59b42843c..7b6368bf8974 100644 --- a/arch/i386/kernel/ptrace.c +++ b/arch/i386/kernel/ptrace.c @@ -271,6 +271,8 @@ static void clear_singlestep(struct task_struct *child) void ptrace_disable(struct task_struct *child) { clear_singlestep(child); + clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); } /* @@ -509,15 +511,20 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data) } break; + case PTRACE_SYSEMU: /* continue and stop at next syscall, which will not be executed */ case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ case PTRACE_CONT: /* restart after signal. */ ret = -EIO; if (!valid_signal(data)) break; - if (request == PTRACE_SYSCALL) { + if (request == PTRACE_SYSEMU) { + set_tsk_thread_flag(child, TIF_SYSCALL_EMU); + clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + } else if (request == PTRACE_SYSCALL) { set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); - } - else { + clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); + } else { + clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); } child->exit_code = data; @@ -542,10 +549,17 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data) wake_up_process(child); break; + case PTRACE_SYSEMU_SINGLESTEP: /* Same as SYSEMU, but singlestep if not syscall */ case PTRACE_SINGLESTEP: /* set the trap flag. */ ret = -EIO; if (!valid_signal(data)) break; + + if (request == PTRACE_SYSEMU_SINGLESTEP) + set_tsk_thread_flag(child, TIF_SYSCALL_EMU); + else + clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); + clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); set_singlestep(child); child->exit_code = data; @@ -678,27 +692,58 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code) * - triggered by current->work.syscall_trace */ __attribute__((regparm(3))) -void do_syscall_trace(struct pt_regs *regs, int entryexit) +int do_syscall_trace(struct pt_regs *regs, int entryexit) { - /* do the secure computing check first */ - secure_computing(regs->orig_eax); + int is_sysemu = test_thread_flag(TIF_SYSCALL_EMU); + /* + * With TIF_SYSCALL_EMU set we want to ignore TIF_SINGLESTEP for syscall + * interception + */ + int is_singlestep = !is_sysemu && test_thread_flag(TIF_SINGLESTEP); + int ret = 0; - if (unlikely(current->audit_context) && entryexit) - audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), regs->eax); + /* do the secure computing check first */ + if (!entryexit) + secure_computing(regs->orig_eax); + + if (unlikely(current->audit_context)) { + if (entryexit) + audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), + regs->eax); + /* Debug traps, when using PTRACE_SINGLESTEP, must be sent only + * on the syscall exit path. Normally, when TIF_SYSCALL_AUDIT is + * not used, entry.S will call us only on syscall exit, not + * entry; so when TIF_SYSCALL_AUDIT is used we must avoid + * calling send_sigtrap() on syscall entry. + * + * Note that when PTRACE_SYSEMU_SINGLESTEP is used, + * is_singlestep is false, despite his name, so we will still do + * the correct thing. + */ + else if (is_singlestep) + goto out; + } if (!(current->ptrace & PT_PTRACED)) goto out; + /* If a process stops on the 1st tracepoint with SYSCALL_TRACE + * and then is resumed with SYSEMU_SINGLESTEP, it will come in + * here. We have to check this and return */ + if (is_sysemu && entryexit) + return 0; + /* Fake a debug trap */ - if (test_thread_flag(TIF_SINGLESTEP)) + if (is_singlestep) send_sigtrap(current, regs, 0); - if (!test_thread_flag(TIF_SYSCALL_TRACE)) + if (!test_thread_flag(TIF_SYSCALL_TRACE) && !is_sysemu) goto out; /* the 0x80 provides a way for the tracing parent to distinguish between a syscall stop and SIGTRAP delivery */ - ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); + /* Note that the debugger could change the result of test_thread_flag!*/ + ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80:0)); /* * this isn't the same as continuing with a signal, but it will do @@ -709,9 +754,17 @@ void do_syscall_trace(struct pt_regs *regs, int entryexit) send_sig(current->exit_code, current, 1); current->exit_code = 0; } - out: + ret = is_sysemu; +out: if (unlikely(current->audit_context) && !entryexit) audit_syscall_entry(current, AUDIT_ARCH_I386, regs->orig_eax, regs->ebx, regs->ecx, regs->edx, regs->esi); - + if (ret == 0) + return 0; + + regs->orig_eax = -1; /* force skip of syscall restarting */ + if (unlikely(current->audit_context)) + audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), + regs->eax); + return 1; } |