| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Verify longjmp fortify checking does not reject signal stacks. |
| 2 | |
| 3 | Test case mostly written by Paolo Bonzini <pbonzini@redhat.com>. */ |
| 4 | #include <assert.h> |
| 5 | #include <setjmp.h> |
| 6 | #include <signal.h> |
| 7 | #include <stdio.h> |
| 8 | #include <stdlib.h> |
| 9 | #include <sys/types.h> |
| 10 | #include <sys/time.h> |
| 11 | #include <sys/resource.h> |
| 12 | |
| 13 | |
| 14 | static jmp_buf mainloop; |
| 15 | static sigset_t mainsigset; |
| 16 | static int pass; |
| 17 | |
| 18 | |
| 19 | static void |
| 20 | stackoverflow_handler (int sig) |
| 21 | { |
| 22 | stack_t altstack; |
| 23 | /* Sanity check to keep test from looping forever (in case the longjmp |
| 24 | chk code is slightly broken). */ |
| 25 | pass++; |
| 26 | assert (pass < 5); |
| 27 | sigaltstack (NULL, &altstack); |
| 28 | /* Using printf is not really kosher in signal handlers but we know |
| 29 | it will work. */ |
| 30 | printf ("%*sin signal handler\n", pass, ""); |
| 31 | if (altstack.ss_flags & SS_ONSTACK) |
| 32 | printf ("%*son alternate stack\n", pass, ""); |
| 33 | siglongjmp (mainloop, pass); |
| 34 | } |
| 35 | |
| 36 | |
| 37 | static volatile int * |
| 38 | recurse_1 (int n, volatile int *p) |
| 39 | { |
| 40 | if (n >= 0) |
| 41 | *recurse_1 (n + 1, p) += n; |
| 42 | return p; |
| 43 | } |
| 44 | |
| 45 | |
| 46 | static int |
| 47 | recurse (int n) |
| 48 | { |
| 49 | int sum = 0; |
| 50 | return *recurse_1 (n, &sum); |
| 51 | } |
| 52 | |
| 53 | |
| 54 | static int |
| 55 | do_test (void) |
| 56 | { |
| 57 | char mystack[SIGSTKSZ]; |
| 58 | stack_t altstack; |
| 59 | struct sigaction action; |
| 60 | sigset_t emptyset; |
| 61 | /* Before starting the endless recursion, try to be friendly to the user's |
| 62 | machine. On some Linux 2.2.x systems, there is no stack limit for user |
| 63 | processes at all. We don't want to kill such systems. */ |
| 64 | struct rlimit rl; |
| 65 | rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */ |
| 66 | setrlimit (RLIMIT_STACK, &rl); |
| 67 | /* Install the alternate stack. */ |
| 68 | altstack.ss_sp = mystack; |
| 69 | altstack.ss_size = sizeof (mystack); |
| 70 | altstack.ss_flags = 0; /* no SS_DISABLE */ |
| 71 | if (sigaltstack (&altstack, NULL) < 0) |
| 72 | { |
| 73 | puts ("first sigaltstack failed"); |
| 74 | return 0; |
| 75 | } |
| 76 | /* Install the SIGSEGV handler. */ |
| 77 | sigemptyset (&action.sa_mask); |
| 78 | action.sa_handler = &stackoverflow_handler; |
| 79 | action.sa_flags = SA_ONSTACK; |
| 80 | sigaction (SIGSEGV, &action, (struct sigaction *) NULL); |
| 81 | sigaction (SIGBUS, &action, (struct sigaction *) NULL); |
| 82 | |
| 83 | /* Save the current signal mask. */ |
| 84 | sigemptyset (&emptyset); |
| 85 | sigprocmask (SIG_BLOCK, &emptyset, &mainsigset); |
| 86 | |
| 87 | /* Provoke two stack overflows in a row. */ |
| 88 | if (sigsetjmp (mainloop, 1) != 0) |
| 89 | { |
| 90 | assert (pass != 0); |
| 91 | printf ("%*sout of signal handler\n", pass, ""); |
| 92 | } |
| 93 | else |
| 94 | assert (pass == 0); |
| 95 | |
| 96 | sigaltstack (NULL, &altstack); |
| 97 | if (altstack.ss_flags & SS_ONSTACK) |
| 98 | printf ("%*son alternate stack\n", pass, ""); |
| 99 | else |
| 100 | printf ("%*snot on alternate stack\n", pass, ""); |
| 101 | |
| 102 | if (pass < 2) |
| 103 | { |
| 104 | recurse (0); |
| 105 | puts ("recurse call returned"); |
| 106 | return 2; |
| 107 | } |
| 108 | |
| 109 | altstack.ss_flags |= SS_DISABLE; |
| 110 | if (sigaltstack (&altstack, NULL) == -1) |
| 111 | printf ("disabling alternate stack failed\n"); |
| 112 | else |
| 113 | printf ("disabling alternate stack succeeded \n"); |
| 114 | |
| 115 | return 0; |
| 116 | } |
| 117 | |
| 118 | #define TEST_FUNCTION do_test () |
| 119 | #include "../test-skeleton.c" |