From 8dcb6d0af07fda3607b541857e4f3970a74ed55b Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Tue, 26 Apr 2022 14:23:02 +0200 Subject: 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 --- dlfcn/dladdr.c | 2 +- dlfcn/dladdr1.c | 2 +- dlfcn/dlclose.c | 2 +- dlfcn/dlerror.c | 2 +- dlfcn/dlinfo.c | 2 +- dlfcn/dlmopen.c | 2 +- dlfcn/dlopen.c | 2 +- dlfcn/dlopenold.c | 2 +- dlfcn/dlsym.c | 2 +- dlfcn/dlvsym.c | 2 +- elf/Makefile | 6 +++ elf/dl-libc.c | 8 ++-- elf/tst-audit26.c | 35 +++++++++++++++++ elf/tst-auditmod26.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++ 14 files changed, 159 insertions(+), 14 deletions(-) create mode 100644 elf/tst-audit26.c create mode 100644 elf/tst-auditmod26.c diff --git a/dlfcn/dladdr.c b/dlfcn/dladdr.c index ead117326f..d188d0e289 100644 --- a/dlfcn/dladdr.c +++ b/dlfcn/dladdr.c @@ -24,7 +24,7 @@ int __dladdr (const void *address, Dl_info *info) { #ifdef SHARED - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dladdr (address, info); #endif return _dl_addr (address, info, NULL, NULL); diff --git a/dlfcn/dladdr1.c b/dlfcn/dladdr1.c index 5dadfd1220..e0c9526c90 100644 --- a/dlfcn/dladdr1.c +++ b/dlfcn/dladdr1.c @@ -24,7 +24,7 @@ int __dladdr1 (const void *address, Dl_info *info, void **extra, int flags) { #ifdef SHARED - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dladdr1 (address, info, extra, flags); #endif diff --git a/dlfcn/dlclose.c b/dlfcn/dlclose.c index a9921c3169..aab88c47fc 100644 --- a/dlfcn/dlclose.c +++ b/dlfcn/dlclose.c @@ -24,7 +24,7 @@ int __dlclose (void *handle) { #ifdef SHARED - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dlclose (handle); #endif diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c index 3bf6049e3c..b899d252a1 100644 --- a/dlfcn/dlerror.c +++ b/dlfcn/dlerror.c @@ -32,7 +32,7 @@ char * __dlerror (void) { # ifdef SHARED - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dlerror (); # endif diff --git a/dlfcn/dlinfo.c b/dlfcn/dlinfo.c index fc63c02681..068db5260c 100644 --- a/dlfcn/dlinfo.c +++ b/dlfcn/dlinfo.c @@ -89,7 +89,7 @@ dlinfo_implementation (void *handle, int request, void *arg) int ___dlinfo (void *handle, int request, void *arg) { - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dlinfo (handle, request, arg); else return dlinfo_implementation (handle, request, arg); diff --git a/dlfcn/dlmopen.c b/dlfcn/dlmopen.c index 2437f5ce22..b41778f16c 100644 --- a/dlfcn/dlmopen.c +++ b/dlfcn/dlmopen.c @@ -80,7 +80,7 @@ dlmopen_implementation (Lmid_t nsid, const char *file, int mode, void * ___dlmopen (Lmid_t nsid, const char *file, int mode) { - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dlmopen (nsid, file, mode, RETURN_ADDRESS (0)); else return dlmopen_implementation (nsid, file, mode, RETURN_ADDRESS (0)); diff --git a/dlfcn/dlopen.c b/dlfcn/dlopen.c index 846ca38338..2696dde4b1 100644 --- a/dlfcn/dlopen.c +++ b/dlfcn/dlopen.c @@ -75,7 +75,7 @@ dlopen_implementation (const char *file, int mode, void *dl_caller) void * ___dlopen (const char *file, int mode) { - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dlopen (file, mode, RETURN_ADDRESS (0)); else return dlopen_implementation (file, mode, RETURN_ADDRESS (0)); diff --git a/dlfcn/dlopenold.c b/dlfcn/dlopenold.c index 67601434df..5c21a00496 100644 --- a/dlfcn/dlopenold.c +++ b/dlfcn/dlopenold.c @@ -70,7 +70,7 @@ __dlopen_nocheck (const char *file, int mode) mode |= RTLD_LAZY; args.mode = mode; - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dlopen (file, mode, RETURN_ADDRESS (0)); return _dlerror_run (dlopen_doit, &args) ? NULL : args.new; diff --git a/dlfcn/dlsym.c b/dlfcn/dlsym.c index a71f8ae247..2e9ff98e79 100644 --- a/dlfcn/dlsym.c +++ b/dlfcn/dlsym.c @@ -62,7 +62,7 @@ dlsym_implementation (void *handle, const char *name, void *dl_caller) void * ___dlsym (void *handle, const char *name) { - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dlsym (handle, name, RETURN_ADDRESS (0)); else return dlsym_implementation (handle, name, RETURN_ADDRESS (0)); diff --git a/dlfcn/dlvsym.c b/dlfcn/dlvsym.c index 72219d6da6..caa46ba1e0 100644 --- a/dlfcn/dlvsym.c +++ b/dlfcn/dlvsym.c @@ -65,7 +65,7 @@ dlvsym_implementation (void *handle, const char *name, const char *version, void * ___dlvsym (void *handle, const char *name, const char *version) { - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->dlvsym (handle, name, version, RETURN_ADDRESS (0)); else diff --git a/elf/Makefile b/elf/Makefile index 8ed6c3b0b1..e4907d5de9 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -390,6 +390,7 @@ tests += \ tst-audit24d \ tst-audit25a \ tst-audit25b \ + tst-audit26 \ tst-auditmany \ tst-auxobj \ tst-auxobj-dlopen \ @@ -767,6 +768,7 @@ modules-names = \ tst-auditmod24c \ tst-auditmod24d \ tst-auditmod25 \ + tst-auditmod26 \ tst-auxvalmod \ tst-big-note-lib \ tst-deep1mod1 \ @@ -2286,6 +2288,10 @@ $(objpfx)tst-audit25b: $(objpfx)tst-audit25mod1.so \ LDFLAGS-tst-audit25b = -Wl,-z,now tst-audit25b-ARGS = -- $(host-test-program-cmd) +$(objpfx)tst-audit26.out: $(objpfx)tst-auditmod26.so +$(objpfx)tst-auditmod26.so: $(libsupport) +tst-audit26-ENV = LD_AUDIT=$(objpfx)tst-auditmod26.so + # tst-sonamemove links against an older implementation of the library. LDFLAGS-tst-sonamemove-linkmod1.so = \ -Wl,--version-script=tst-sonamemove-linkmod1.map \ diff --git a/elf/dl-libc.c b/elf/dl-libc.c index a7180d0af8..266e068da6 100644 --- a/elf/dl-libc.c +++ b/elf/dl-libc.c @@ -156,7 +156,7 @@ __libc_dlopen_mode (const char *name, int mode) args.caller_dlopen = RETURN_ADDRESS (0); #ifdef SHARED - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->libc_dlopen_mode (name, mode); #endif return dlerror_run (do_dlopen, &args) ? NULL : (void *) args.map; @@ -184,7 +184,7 @@ __libc_dlsym (void *map, const char *name) args.name = name; #ifdef SHARED - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->libc_dlsym (map, name); #endif return (dlerror_run (do_dlsym, &args) ? NULL @@ -198,7 +198,7 @@ void * __libc_dlvsym (void *map, const char *name, const char *version) { #ifdef SHARED - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->libc_dlvsym (map, name, version); #endif @@ -221,7 +221,7 @@ int __libc_dlclose (void *map) { #ifdef SHARED - if (!rtld_active ()) + if (GLRO (dl_dlfcn_hook) != NULL) return GLRO (dl_dlfcn_hook)->libc_dlclose (map); #endif return dlerror_run (do_dlclose, map); diff --git a/elf/tst-audit26.c b/elf/tst-audit26.c new file mode 100644 index 0000000000..3f920e83ba --- /dev/null +++ b/elf/tst-audit26.c @@ -0,0 +1,35 @@ +/* Check the usability of functions in audit modules. + 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 + . */ + +#include + +#include +#include + +static int +do_test (void) +{ + /* Check that the audit module has been loaded. */ + void *handle = xdlopen ("mapped to libc", RTLD_LOCAL | RTLD_NOW); + TEST_VERIFY (handle + == xdlopen (LIBC_SO, RTLD_LOCAL | RTLD_NOW | RTLD_NOLOAD)); + + return 0; +} + +#include 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 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 + . */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +unsigned int +la_version (unsigned int current) +{ + /* Exercise various 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; +} -- cgit 1.4.1