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author | Florian Weimer <fweimer@redhat.com> | 2022-04-26 14:23:02 +0200 |
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committer | Florian Weimer <fweimer@redhat.com> | 2022-04-26 14:24:36 +0200 |
commit | 8dcb6d0af07fda3607b541857e4f3970a74ed55b (patch) | |
tree | 06a15719ac286241c9faf9bfd4a802d57ee08bc8 /elf/tst-auditmod26.c | |
parent | c935789bdf40ba22b5698da869d3a4789797e09f (diff) | |
download | glibc-8dcb6d0af07fda3607b541857e4f3970a74ed55b.tar.gz glibc-8dcb6d0af07fda3607b541857e4f3970a74ed55b.tar.xz glibc-8dcb6d0af07fda3607b541857e4f3970a74ed55b.zip |
dlfcn: Do not use rtld_active () to determine ld.so state (bug 29078)
When audit modules are loaded, ld.so initialization is not yet complete, and rtld_active () returns false even though ld.so is mostly working. Instead, the static dlopen hook is used, but that does not work at all because this is not a static dlopen situation. Commit 466c1ea15f461edb8e3ffaf5d86d708876343bbf ("dlfcn: Rework static dlopen hooks") moved the hook pointer into _rtld_global_ro, which means that separate protection is not needed anymore and the hook pointer can be checked directly. The guard for disabling libio vtable hardening in _IO_vtable_check should stay for now. Fixes commit 8e1472d2c1e25e6eabc2059170731365f6d5b3d1 ("ld.so: Examine GLRO to detect inactive loader [BZ #20204]"). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'elf/tst-auditmod26.c')
-rw-r--r-- | elf/tst-auditmod26.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/elf/tst-auditmod26.c b/elf/tst-auditmod26.c new file mode 100644 index 0000000000..db7ba95abe --- /dev/null +++ b/elf/tst-auditmod26.c @@ -0,0 +1,104 @@ +/* Check the usability of <dlfcn.h> functions in audit modules. Audit module. + Copyright (C) 2022 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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, see + <https://www.gnu.org/licenses/>. */ + +#include <dlfcn.h> +#include <first-versions.h> +#include <gnu/lib-names.h> +#include <link.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> + +#include <support/check.h> +#include <support/xdlfcn.h> + +unsigned int +la_version (unsigned int current) +{ + /* Exercise various <dlfcn.h> functions. */ + + /* Check dlopen, dlsym, dlclose. */ + void *handle = xdlopen (LIBM_SO, RTLD_LOCAL | RTLD_NOW); + void *ptr = xdlsym (handle, "sincos"); + TEST_VERIFY (ptr != NULL); + ptr = dlsym (handle, "SINCOS"); + TEST_VERIFY (ptr == NULL); + const char *message = dlerror (); + TEST_VERIFY (strstr (message, ": undefined symbol: SINCOS") != NULL); + ptr = dlsym (handle, "SINCOS"); + TEST_VERIFY (ptr == NULL); + xdlclose (handle); + TEST_COMPARE_STRING (dlerror (), NULL); + + handle = xdlopen (LIBC_SO, RTLD_LOCAL | RTLD_NOW | RTLD_NOLOAD); + + /* Check dlvsym. _exit is unlikely to gain another symbol + version. */ + TEST_VERIFY (xdlsym (handle, "_exit") + == xdlvsym (handle, "_exit", FIRST_VERSION_libc__exit_STRING)); + + /* Check dlinfo. */ + { + void *handle2 = NULL; + TEST_COMPARE (dlinfo (handle, RTLD_DI_LINKMAP, &handle2), 0); + TEST_VERIFY (handle2 == handle); + } + + /* Check dladdr and dladdr1. */ + Dl_info info = { }; + TEST_VERIFY (dladdr (&_exit, &info) != 0); + if (strcmp (info.dli_sname, "_Exit") != 0) /* _Exit is an alias. */ + TEST_COMPARE_STRING (info.dli_sname, "_exit"); + TEST_VERIFY (info.dli_saddr == &_exit); + TEST_VERIFY (strstr (info.dli_fname, LIBC_SO)); + void *extra_info; + memset (&info, 0, sizeof (info)); + TEST_VERIFY (dladdr1 (&_exit, &info, &extra_info, RTLD_DL_LINKMAP) != 0); + TEST_VERIFY (extra_info == handle); + + /* Verify that dlmopen creates a new namespace. */ + void *dlmopen_handle = xdlmopen (LM_ID_NEWLM, LIBC_SO, RTLD_NOW); + TEST_VERIFY (dlmopen_handle != handle); + memset (&info, 0, sizeof (info)); + extra_info = NULL; + ptr = xdlsym (dlmopen_handle, "_exit"); + TEST_VERIFY (dladdr1 (ptr, &info, &extra_info, RTLD_DL_LINKMAP) != 0); + TEST_VERIFY (extra_info == dlmopen_handle); + xdlclose (dlmopen_handle); + + /* Terminate the process with an error state. This does not happen + automatically because the audit module state is not shared with + the main program. */ + if (support_record_failure_is_failed ()) + { + fflush (stdout); + fflush (stderr); + _exit (1); + } + + return LAV_CURRENT; +} + +char * +la_objsearch (const char *name, uintptr_t *cookie, unsigned int flag) +{ + if (strcmp (name, "mapped to libc") == 0) + return (char *) LIBC_SO; + else + return (char *) name; +} |