diff options
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/Makefile | 11 | ||||
| -rw-r--r-- | elf/Versions | 4 | ||||
| -rw-r--r-- | elf/rtld.c | 54 | ||||
| -rw-r--r-- | elf/stackguard-macros.h | 30 | ||||
| -rw-r--r-- | elf/tst-stackguard1-static.c | 1 | ||||
| -rw-r--r-- | elf/tst-stackguard1.c | 196 |
6 files changed, 270 insertions, 26 deletions
diff --git a/elf/Makefile b/elf/Makefile index d988baca3b..c43eb02f5b 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -87,7 +87,8 @@ distribute := rtld-Rules \ unload3mod1.c unload3mod2.c unload3mod3.c unload3mod4.c \ unload4mod1.c unload4mod2.c unload4mod3.c unload4mod4.c \ unload6mod1.c unload6mod2.c unload6mod3.c tst-auditmod1.c \ - order2mod1.c order2mod2.c order2mod3.c order2mod4.c + order2mod1.c order2mod2.c order2mod3.c order2mod4.c \ + tst-stackguard1.c tst-stackguard1-static.c CFLAGS-dl-runtime.c = -fexceptions -fasynchronous-unwind-tables CFLAGS-dl-lookup.c = -fexceptions -fasynchronous-unwind-tables @@ -140,7 +141,7 @@ ifeq (yes,$(have-initfini-array)) tests += tst-array1 tst-array2 tst-array3 tst-array4 endif ifeq (yes,$(build-static)) -tests-static = tst-tls1-static tst-tls2-static +tests-static = tst-tls1-static tst-tls2-static tst-stackguard1-static ifeq (yesyesyes,$(build-static)$(build-shared)$(elf)) tests-static += tst-tls9-static tst-tls9-static-ENV = \ @@ -162,7 +163,8 @@ tests += loadtest restest1 preloadtest loadfail multiload origtest resolvfail \ tst-tls10 tst-tls11 tst-tls12 tst-tls13 tst-tls14 tst-tls15 tst-align \ tst-align2 $(tests-execstack-$(have-z-execstack)) tst-dlmodcount \ tst-dlopenrpath tst-deep1 tst-dlmopen1 tst-dlmopen2 tst-dlmopen3 \ - unload3 unload4 unload5 unload6 tst-audit1 tst-global1 order2 + unload3 unload4 unload5 unload6 tst-audit1 tst-global1 order2 \ + tst-stackguard1 # reldep9 test-srcs = tst-pathopt tests-vis-yes = vismain @@ -843,3 +845,6 @@ $(objpfx)order2mod1.so: $(objpfx)order2mod4.so $(objpfx)order2mod4.so: $(objpfx)order2mod3.so $(objpfx)order2mod2.so: $(objpfx)order2mod3.so order2mod2.so-no-z-defs = yes + +tst-stackguard1-ARGS = --command "$(built-program-cmd) --child" +tst-stackguard1-static-ARGS = --command "$(objpfx)tst-stackguard1-static --child" diff --git a/elf/Versions b/elf/Versions index aaacf3e4ea..9c53f1615e 100644 --- a/elf/Versions +++ b/elf/Versions @@ -43,6 +43,10 @@ ld { # runtime interface to TLS __tls_get_addr; } + GLIBC_2.4 { + # stack canary + __stack_chk_guard; + } GLIBC_PRIVATE { # Those are in the dynamic linker, but used by libc.so. __libc_enable_secure; diff --git a/elf/rtld.c b/elf/rtld.c index bd171e977d..21365af2ba 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -80,6 +80,12 @@ char **_dl_argv attribute_relro = NULL; #endif INTDEF(_dl_argv) +#ifndef THREAD_SET_STACK_GUARD +/* Only exported for architectures that don't store the stack guard canary + in thread local area. */ +uintptr_t __stack_chk_guard attribute_relro; +#endif + /* Nonzero if we were run directly. */ unsigned int _dl_skip_args attribute_relro attribute_hidden; @@ -1398,9 +1404,6 @@ ld.so does not support TLS, but program uses it!\n"); always allocate the static block, we never defer it even if no DF_STATIC_TLS bit is set. The reason is that we know glibc will use the static model. */ -# ifndef TLS_INIT_TP_EXPENSIVE -# define TLS_INIT_TP_EXPENSIVE 0 -# endif /* Since we start using the auditing DSOs right away we need to initialize the data structures now. */ @@ -1807,10 +1810,18 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n", used. Trying to do it lazily is too hairy to try when there could be multiple threads (from a non-TLS-using libpthread). */ bool was_tls_init_tp_called = tls_init_tp_called; - if (tcbp == NULL && (!TLS_INIT_TP_EXPENSIVE || GL(dl_tls_max_dtv_idx) > 0)) + if (tcbp == NULL) tcbp = init_tls (); #endif + /* Set up the stack checker's canary. */ + uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (); +#ifdef THREAD_SET_STACK_GUARD + THREAD_SET_STACK_GUARD (stack_chk_guard); +#else + __stack_chk_guard = stack_chk_guard; +#endif + if (__builtin_expect (mode, normal) != normal) { /* We were run just to list the shared libraries. It is @@ -2230,29 +2241,26 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n", #endif #ifdef USE_TLS - if (GL(dl_tls_max_dtv_idx) > 0 || USE___THREAD || !TLS_INIT_TP_EXPENSIVE) - { - if (!was_tls_init_tp_called && GL(dl_tls_max_dtv_idx) > 0) - ++GL(dl_tls_generation); + if (!was_tls_init_tp_called && GL(dl_tls_max_dtv_idx) > 0) + ++GL(dl_tls_generation); - /* Now that we have completed relocation, the initializer data - for the TLS blocks has its final values and we can copy them - into the main thread's TLS area, which we allocated above. */ - _dl_allocate_tls_init (tcbp); + /* Now that we have completed relocation, the initializer data + for the TLS blocks has its final values and we can copy them + into the main thread's TLS area, which we allocated above. */ + _dl_allocate_tls_init (tcbp); - /* And finally install it for the main thread. If ld.so itself uses - TLS we know the thread pointer was initialized earlier. */ - if (! tls_init_tp_called) - { - const char *lossage = TLS_INIT_TP (tcbp, USE___THREAD); - if (__builtin_expect (lossage != NULL, 0)) - _dl_fatal_printf ("cannot set up thread-local storage: %s\n", - lossage); - } + /* And finally install it for the main thread. If ld.so itself uses + TLS we know the thread pointer was initialized earlier. */ + if (! tls_init_tp_called) + { + const char *lossage = TLS_INIT_TP (tcbp, USE___THREAD); + if (__builtin_expect (lossage != NULL, 0)) + _dl_fatal_printf ("cannot set up thread-local storage: %s\n", + lossage); } - else +#else + NONTLS_INIT_TP; #endif - NONTLS_INIT_TP; #ifdef SHARED /* Auditing checkpoint: we have added all objects. */ diff --git a/elf/stackguard-macros.h b/elf/stackguard-macros.h new file mode 100644 index 0000000000..0fbf4d2c0b --- /dev/null +++ b/elf/stackguard-macros.h @@ -0,0 +1,30 @@ +#include <stdint.h> + +#ifdef __i386__ +# define STACK_CHK_GUARD \ + ({ uintptr_t x; asm ("movl %%gs:0x14, %0" : "=r" (x)); x; }) +#elif defined __x86_64__ +# define STACK_CHK_GUARD \ + ({ uintptr_t x; asm ("movq %%fs:0x28, %0" : "=r" (x)); x; }) +#elif defined __powerpc64__ +# define STACK_CHK_GUARD \ + ({ uintptr_t x; asm ("ld %0,-28688(13)" : "=r" (x)); x; }) +#elif defined __powerpc__ +# define STACK_CHK_GUARD \ + ({ uintptr_t x; asm ("lwz %0,-28680(2)" : "=r" (x)); x; }) +#elif defined __sparc__ && defined __arch64__ +# define STACK_CHK_GUARD \ + ({ uintptr_t x; asm ("ldx [%%g7+0x28], %0" : "=r" (x)); x; }) +#elif defined __sparc__ +# define STACK_CHK_GUARD \ + ({ uintptr_t x; asm ("ld [%%g7+0x14], %0" : "=r" (x)); x; }) +#elif defined __s390x__ +# define STACK_CHK_GUARD \ + ({ uintptr_t x; asm ("ear %0,%a0; sllg %0,%0,32; ear %0,%a1; lg %0,0x28(%0)" : "=r" (x)); x; }) +#elif defined __s390__ +# define STACK_CHK_GUARD \ + ({ uintptr_t x; asm ("ear %0,%%a0; l %0,0x14(%0)" : "=r" (x)); x; }) +#else +extern uintptr_t __stack_chk_guard; +# define STACK_CHK_GUARD __stack_chk_guard +#endif diff --git a/elf/tst-stackguard1-static.c b/elf/tst-stackguard1-static.c new file mode 100644 index 0000000000..db1e21554d --- /dev/null +++ b/elf/tst-stackguard1-static.c @@ -0,0 +1 @@ +#include "tst-stackguard1.c" diff --git a/elf/tst-stackguard1.c b/elf/tst-stackguard1.c new file mode 100644 index 0000000000..480f9297d0 --- /dev/null +++ b/elf/tst-stackguard1.c @@ -0,0 +1,196 @@ +/* Copyright (C) 2005 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Jakub Jelinek <jakub@redhat.com>, 2005. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <errno.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/wait.h> +#include <stackguard-macros.h> +#include <unistd.h> + +static const char *command; +static bool child; +static uintptr_t stack_chk_guard_copy; +static bool stack_chk_guard_copy_set; +static int fds[2]; + +static void __attribute__ ((constructor)) +con (void) +{ + stack_chk_guard_copy = STACK_CHK_GUARD; + stack_chk_guard_copy_set = true; +} + +static int +uintptr_t_cmp (const void *a, const void *b) +{ + if (*(uintptr_t *) a < *(uintptr_t *) b) + return 1; + if (*(uintptr_t *) a > *(uintptr_t *) b) + return -1; + return 0; +} + +static int +do_test (void) +{ + if (!stack_chk_guard_copy_set) + { + puts ("constructor has not been run"); + return 1; + } + + if (stack_chk_guard_copy != STACK_CHK_GUARD) + { + puts ("STACK_CHK_GUARD changed between constructor and do_test"); + return 1; + } + + if (child) + { + write (2, &stack_chk_guard_copy, sizeof (stack_chk_guard_copy)); + return 0; + } + + if (command == NULL) + { + puts ("missing --command or --child argument"); + return 1; + } + +#define N 16 + uintptr_t child_stack_chk_guards[N + 1]; + child_stack_chk_guards[N] = stack_chk_guard_copy; + int i; + for (i = 0; i < N; ++i) + { + if (pipe (fds) < 0) + { + printf ("couldn't create pipe: %m\n"); + return 1; + } + + pid_t pid = fork (); + if (pid < 0) + { + printf ("fork failed: %m\n"); + return 1; + } + + if (!pid) + { + if (stack_chk_guard_copy != STACK_CHK_GUARD) + { + puts ("STACK_CHK_GUARD changed after fork"); + exit (1); + } + + close (fds[0]); + close (2); + dup2 (fds[1], 2); + close (fds[1]); + + system (command); + exit (0); + } + + close (fds[1]); + + if (TEMP_FAILURE_RETRY (read (fds[0], &child_stack_chk_guards[i], + sizeof (uintptr_t))) != sizeof (uintptr_t)) + { + puts ("could not read stack_chk_guard value from child"); + return 1; + } + + close (fds[0]); + + pid_t termpid; + int status; + termpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)); + if (termpid == -1) + { + printf ("waitpid failed: %m\n"); + return 1; + } + else if (termpid != pid) + { + printf ("waitpid returned %ld != %ld\n", + (long int) termpid, (long int) pid); + return 1; + } + else if (!WIFEXITED (status) || WEXITSTATUS (status)) + { + puts ("child hasn't exited with exit status 0"); + return 1; + } + } + + qsort (child_stack_chk_guards, N + 1, sizeof (uintptr_t), uintptr_t_cmp); + + uintptr_t default_guard = 0; + unsigned char *p = (unsigned char *) &default_guard; + p[sizeof (uintptr_t) - 1] = 255; + p[sizeof (uintptr_t) - 2] = '\n'; + p[0] = 0; + + /* Test if the stack guard canaries are either randomized, + or equal to the default stack guard canary value. + Even with randomized stack guards it might happen + that the random number generator generates the same + values, but if that happens in more than half from + the 16 runs, something is very wrong. */ + int ndifferences = 0; + int ndefaults = 0; + for (i = 0; i < N; ++i) + { + if (child_stack_chk_guards[i] != child_stack_chk_guards[i+1]) + ndifferences++; + else if (child_stack_chk_guards[i] == default_guard) + ndefaults++; + } + + printf ("differences %d defaults %d\n", ndifferences, ndefaults); + + if (ndifferences < N / 2 && ndefaults < N / 2) + { + puts ("stack guard canaries are not randomized enough"); + puts ("nor equal to the default canary value"); + return 1; + } + + return 0; +} + +#define OPT_COMMAND 10000 +#define OPT_CHILD 10001 +#define CMDLINE_OPTIONS \ + { "command", required_argument, NULL, OPT_COMMAND }, \ + { "child", no_argument, NULL, OPT_CHILD }, +#define CMDLINE_PROCESS \ + case OPT_COMMAND: \ + command = optarg; \ + break; \ + case OPT_CHILD: \ + child = true; \ + break; +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" |