194 lines
6.0 KiB
Diff
194 lines
6.0 KiB
Diff
From 25e8461cbe56a3f035df145d9d762b65aa3eedb7 Mon Sep 17 00:00:00 2001
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From: Jorge Gomes <jorge@lip.pt>
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Date: Mon, 13 Feb 2017 20:37:17 +0000
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Subject: [PATCH] fix event.c for seccomp and ptrace
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---
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src/tracee/event.c | 129 ++++++++++++++++++++++++++++++++++++-----------------
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1 file changed, 88 insertions(+), 41 deletions(-)
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diff --git src/tracee/event.c src/tracee/event.c
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index bafc3c5..64166f6 100644
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--- src/tracee/event.c
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+++ src/tracee/event.c
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@@ -20,6 +20,7 @@
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* 02110-1301 USA.
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*/
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+#include <stdio.h>
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#include <sched.h> /* CLONE_*, */
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#include <sys/types.h> /* pid_t, */
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#include <sys/ptrace.h> /* ptrace(1), PTRACE_*, */
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@@ -47,6 +48,7 @@
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#include "attribute.h"
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#include "compat.h"
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+
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/**
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* Start @tracee->exe with the given @argv[]. This function
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* returns -errno if an error occurred, otherwise 0.
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@@ -205,6 +207,27 @@ static void print_talloc_hierarchy(int signum, siginfo_t *siginfo UNUSED, void *
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static int last_exit_status = -1;
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/**
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+ * Check if kernel >= 4.8
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+ */
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+bool is_kernel_4_8(void) {
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+ struct utsname utsname;
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+ int status;
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+ static bool version_48 = false;
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+ static int major = 0;
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+ static int minor = 0;
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+ if (! major) {
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+ status = uname(&utsname);
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+ if (status < 0)
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+ return false;
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+ sscanf(utsname.release, "%d.%d", &major, &minor);
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+ if (major >= 4)
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+ if (minor >= 8)
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+ version_48 = true;
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+ }
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+ return version_48;
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+}
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+
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+/**
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* Check if this instance of PRoot can *technically* handle @tracee.
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*/
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static void check_architecture(Tracee *tracee)
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@@ -362,6 +385,7 @@ int event_loop()
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int handle_tracee_event(Tracee *tracee, int tracee_status)
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{
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static bool seccomp_detected = false;
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+ static bool seccomp_enabled = false;
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pid_t pid = tracee->pid;
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long status;
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int signal;
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@@ -432,6 +456,7 @@ int handle_tracee_event(Tracee *tracee, int tracee_status)
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status = ptrace(PTRACE_SETOPTIONS, tracee->pid, NULL,
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default_ptrace_options | PTRACE_O_TRACESECCOMP);
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if (status < 0) {
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+ seccomp_enabled = false;
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/* ... otherwise use default options only. */
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status = ptrace(PTRACE_SETOPTIONS, tracee->pid, NULL,
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default_ptrace_options);
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@@ -440,8 +465,71 @@ int handle_tracee_event(Tracee *tracee, int tracee_status)
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exit(EXIT_FAILURE);
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}
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}
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+ else {
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+ if (getenv("PROOT_NO_SECCOMP") == NULL)
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+ seccomp_enabled = true;
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+ }
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}
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/* Fall through. */
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+ case SIGTRAP | PTRACE_EVENT_SECCOMP2 << 8:
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+ case SIGTRAP | PTRACE_EVENT_SECCOMP << 8:
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+
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+ if (is_kernel_4_8()) {
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+ if (seccomp_enabled) {
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+ if (!seccomp_detected) {
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+ VERBOSE(tracee, 1, "ptrace acceleration (seccomp mode 2) enabled");
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+ tracee->seccomp = ENABLED;
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+ seccomp_detected = true;
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+ }
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+
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+ unsigned long flags = 0;
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+ status = ptrace(PTRACE_GETEVENTMSG, tracee->pid, NULL, &flags);
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+ if (status < 0)
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+ break;
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+ }
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+ }
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+ else if (signal == (SIGTRAP | PTRACE_EVENT_SECCOMP2 << 8) ||
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+ signal == (SIGTRAP | PTRACE_EVENT_SECCOMP << 8)) {
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+ unsigned long flags = 0;
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+
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+ signal = 0;
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+
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+ if (!seccomp_detected) {
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+ VERBOSE(tracee, 1, "ptrace acceleration (seccomp mode 2) enabled");
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+ tracee->seccomp = ENABLED;
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+ seccomp_detected = true;
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+ }
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+
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+ /* Use the common ptrace flow if seccomp was
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+ * explicitely disabled for this tracee. */
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+ if (tracee->seccomp != ENABLED)
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+ break;
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+
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+ status = ptrace(PTRACE_GETEVENTMSG, tracee->pid, NULL, &flags);
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+ if (status < 0)
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+ break;
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+
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+ /* Use the common ptrace flow when
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+ * sysexit has to be handled. */
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+ if ((flags & FILTER_SYSEXIT) != 0) {
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+ tracee->restart_how = PTRACE_SYSCALL;
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+ break;
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+ }
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+
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+ /* Otherwise, handle the sysenter
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+ * stage right now. */
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+ tracee->restart_how = PTRACE_CONT;
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+ translate_syscall(tracee);
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+
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+ /* This syscall has disabled seccomp, so move
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+ * the ptrace flow back to the common path to
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+ * ensure its sysexit will be handled. */
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+ if (tracee->seccomp == DISABLING)
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+ tracee->restart_how = PTRACE_SYSCALL;
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+ break;
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+ }
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+
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+ /* Fall through. */
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case SIGTRAP | 0x80:
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signal = 0;
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@@ -490,47 +578,6 @@ int handle_tracee_event(Tracee *tracee, int tracee_status)
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}
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break;
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- case SIGTRAP | PTRACE_EVENT_SECCOMP2 << 8:
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- case SIGTRAP | PTRACE_EVENT_SECCOMP << 8: {
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- unsigned long flags = 0;
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-
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- signal = 0;
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-
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- if (!seccomp_detected) {
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- VERBOSE(tracee, 1, "ptrace acceleration (seccomp mode 2) enabled");
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- tracee->seccomp = ENABLED;
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- seccomp_detected = true;
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- }
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-
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- /* Use the common ptrace flow if seccomp was
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- * explicitely disabled for this tracee. */
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- if (tracee->seccomp != ENABLED)
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- break;
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-
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- status = ptrace(PTRACE_GETEVENTMSG, tracee->pid, NULL, &flags);
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- if (status < 0)
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- break;
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-
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- /* Use the common ptrace flow when
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- * sysexit has to be handled. */
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- if ((flags & FILTER_SYSEXIT) != 0) {
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- tracee->restart_how = PTRACE_SYSCALL;
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- break;
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- }
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-
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- /* Otherwise, handle the sysenter
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- * stage right now. */
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- tracee->restart_how = PTRACE_CONT;
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- translate_syscall(tracee);
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-
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- /* This syscall has disabled seccomp, so move
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- * the ptrace flow back to the common path to
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- * ensure its sysexit will be handled. */
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- if (tracee->seccomp == DISABLING)
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- tracee->restart_how = PTRACE_SYSCALL;
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- break;
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- }
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-
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case SIGTRAP | PTRACE_EVENT_VFORK << 8:
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signal = 0;
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(void) new_child(tracee, CLONE_VFORK);
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