| 1 | |
| 2 |
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| 3 | #include <linux/audit.h>
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| 4 | #include <linux/entry-common.h>
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| 5 | #include "common.h"
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| 6 |
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| 7 | #define CREATE_TRACE_POINTS
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| 8 | #include <trace/events/syscalls.h>
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| 9 |
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| 10 | static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
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| 11 | {
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| 12 | if (unlikely(audit_context())) {
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| 13 | unsigned long args[6];
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| 14 |
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| 15 | syscall_get_arguments(current, regs, args);
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| 16 | audit_syscall_entry(syscall, args[0], args[1], args[2], args[3]);
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| 17 | }
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| 18 | }
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| 19 |
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| 20 | long syscall_trace_enter(struct pt_regs *regs, long syscall,
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| 21 | unsigned long work)
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| 22 | {
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| 23 | long ret = 0;
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| 24 |
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| 25 | |
| 26 | * Handle Syscall User Dispatch. This must comes first, since
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| 27 | * the ABI here can be something that doesn't make sense for
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| 28 | * other syscall_work features.
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| 29 |
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| 30 | if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
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| 31 | if (syscall_user_dispatch(regs))
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| 32 | return -1L;
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| 33 | }
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| 34 |
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| 35 |
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| 36 | if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
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| 37 | ret = ptrace_report_syscall_entry(regs);
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| 38 | if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
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| 39 | return -1L;
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| 40 | }
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| 41 |
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| 42 |
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| 43 | if (work & SYSCALL_WORK_SECCOMP) {
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| 44 | ret = __secure_computing();
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| 45 | if (ret == -1L)
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| 46 | return ret;
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| 47 | }
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| 48 |
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| 49 |
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| 50 | syscall = syscall_get_nr(current, regs);
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| 51 |
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| 52 | if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) {
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| 53 | trace_sys_enter(regs, syscall);
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| 54 | |
| 55 | * Probes or BPF hooks in the tracepoint may have changed the
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| 56 | * system call number as well.
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| 57 |
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| 58 | syscall = syscall_get_nr(current, regs);
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| 59 | }
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| 60 |
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| 61 | syscall_enter_audit(regs, syscall);
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| 62 |
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| 63 | return ret ? : syscall;
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| 64 | }
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| 65 |
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| 66 | noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
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| 67 | {
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| 68 | enter_from_user_mode(regs);
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| 69 | instrumentation_begin();
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| 70 | local_irq_enable();
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| 71 | instrumentation_end();
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| 72 | }
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| 73 |
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| 74 | |
| 75 | * If SYSCALL_EMU is set, then the only reason to report is when
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| 76 | * SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP). This syscall
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| 77 | * instruction has been already reported in syscall_enter_from_user_mode().
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| 78 |
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| 79 | static inline bool report_single_step(unsigned long work)
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| 80 | {
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| 81 | if (work & SYSCALL_WORK_SYSCALL_EMU)
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| 82 | return false;
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| 83 |
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| 84 | return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP;
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| 85 | }
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| 86 |
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| 87 | void syscall_exit_work(struct pt_regs *regs, unsigned long work)
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| 88 | {
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| 89 | bool step;
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| 90 |
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| 91 | |
| 92 | * If the syscall was rolled back due to syscall user dispatching,
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| 93 | * then the tracers below are not invoked for the same reason as
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| 94 | * the entry side was not invoked in syscall_trace_enter(): The ABI
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| 95 | * of these syscalls is unknown.
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| 96 |
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| 97 | if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
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| 98 | if (unlikely(current->syscall_dispatch.on_dispatch)) {
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| 99 | current->syscall_dispatch.on_dispatch = false;
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| 100 | return;
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| 101 | }
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| 102 | }
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| 103 |
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| 104 | audit_syscall_exit(regs);
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| 105 |
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| 106 | if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT)
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| 107 | trace_sys_exit(regs, syscall_get_return_value(current, regs));
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| 108 |
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| 109 | step = report_single_step(work);
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| 110 | if (step || work & SYSCALL_WORK_SYSCALL_TRACE)
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| 111 | ptrace_report_syscall_exit(regs, step);
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| 112 | }
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