public inbox for glibc-cvs@sourceware.org help / color / mirror / Atom feed
From: Adhemerval Zanella <azanella@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc/azanella/ld-audit-fixes] elf: Issue audit la_objopen() for vDSO Date: Tue, 9 Nov 2021 18:19:11 +0000 (GMT) [thread overview] Message-ID: <20211109181911.66079385841C@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b0a5630a768dc02fcf87ffb84e6128c11629440e commit b0a5630a768dc02fcf87ffb84e6128c11629440e Author: Adhemerval Zanella <adhemerval.zanella@linaro.org> Date: Mon Jul 19 18:42:26 2021 -0300 elf: Issue audit la_objopen() for vDSO The vDSO is is listed in the link_map chain, but is never the subject of an la_objopen call. A new internal flag __RTLD_VDSO is added that acts as __RTLD_OPENEXEC to allocate the required 'struct auditstate' extra space for the 'struct link_map'. The return value from the callback() is currently ignored, since there is no PLT call involved by glibc when using the vDSO, neither the vDSO are exported directly. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Diff: --- elf/Makefile | 5 +++ elf/dl-object.c | 17 +++++--- elf/rtld.c | 7 +++ elf/setup-vdso.h | 2 +- elf/tst-audit22.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++ elf/tst-auditmod22.c | 37 ++++++++++++++++ include/dlfcn.h | 1 + 7 files changed, 180 insertions(+), 8 deletions(-) diff --git a/elf/Makefile b/elf/Makefile index f685831913..01bbbf5aea 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -230,6 +230,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \ tst-audit19 \ tst-audit20 \ tst-audit21 \ + tst-audit22 \ tst-single_threaded tst-single_threaded-pthread \ tst-tls-ie tst-tls-ie-dlmopen argv0test \ tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \ @@ -322,6 +323,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ tst-auditmod19 \ tst-auditmod20 tst-audit20mod \ tst-auditmod21 \ + tst-auditmod22 \ $(if $(CXX),tst-unique3lib tst-unique3lib2 tst-unique4lib \ tst-nodelete-uniquemod tst-nodelete-rtldmod \ tst-nodelete-zmod \ @@ -1577,6 +1579,9 @@ tst-audit20-ARGS = -- $(host-test-program-cmd) $(objpfx)tst-audit21.out: $(objpfx)tst-auditmod21.so tst-audit21-ENV = LD_AUDIT=$(objpfx)tst-auditmod21.so +$(objpfx)tst-audit22.out: $(objpfx)tst-auditmod22.so +tst-audit22-ARGS = -- $(host-test-program-cmd) + # 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-object.c b/elf/dl-object.c index eb2158a84b..6f26da4310 100644 --- a/elf/dl-object.c +++ b/elf/dl-object.c @@ -59,16 +59,19 @@ _dl_new_object (char *realname, const char *libname, int type, { #ifdef SHARED unsigned int naudit; - if (__glibc_unlikely ((mode & __RTLD_OPENEXEC) != 0)) + if (__glibc_unlikely ((mode & (__RTLD_OPENEXEC | __RTLD_VDSO)) != 0)) { - assert (type == lt_executable); - assert (nsid == LM_ID_BASE); + if (mode & __RTLD_OPENEXEC) + { + assert (type == lt_executable); + assert (nsid == LM_ID_BASE); - /* Ignore the specified libname for the main executable. It is - only known with an explicit loader invocation. */ - libname = ""; + /* Ignore the specified libname for the main executable. It is + only known with an explicit loader invocation. */ + libname = ""; + } - /* We create the map for the executable before we know whether + /* We create the map for the executable and vDSO before we know whether we have auditing libraries and if yes, how many. Assume the worst. */ naudit = DL_NNS; diff --git a/elf/rtld.c b/elf/rtld.c index faba319e5c..55b4eb91f2 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -1879,6 +1879,13 @@ dl_main (const ElfW(Phdr) *phdr, assert (i == npreloads); } +#ifdef NEED_DL_SYSINFO_DSO + /* Now that the audit modules are opened, call la_objopen() for the + vDSO. */ + if (GLRO(dl_sysinfo_map) != NULL) + _dl_audit_objopen (GLRO(dl_sysinfo_map), LM_ID_BASE, true); +#endif + /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD specified some libraries to load, these are inserted before the actual dependencies in the executable's searchlist for symbol resolution. */ diff --git a/elf/setup-vdso.h b/elf/setup-vdso.h index 3f20578046..2b013d974a 100644 --- a/elf/setup-vdso.h +++ b/elf/setup-vdso.h @@ -30,7 +30,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)), We just want our data structures to describe it as if we had just mapped and relocated it normally. */ struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL, - 0, LM_ID_BASE); + __RTLD_VDSO, LM_ID_BASE); if (__glibc_likely (l != NULL)) { l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso) diff --git a/elf/tst-audit22.c b/elf/tst-audit22.c new file mode 100644 index 0000000000..c1b301c4cc --- /dev/null +++ b/elf/tst-audit22.c @@ -0,0 +1,119 @@ +/* Check DTAUDIT and vDSO interaction. + Copyright (C) 2021 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 <errno.h> +#include <getopt.h> +#include <limits.h> +#include <inttypes.h> +#include <string.h> +#include <stdlib.h> +#include <support/capture_subprocess.h> +#include <support/check.h> +#include <support/xstdio.h> +#include <support/support.h> +#include <sys/auxv.h> + +static int restart; +#define CMDLINE_OPTIONS \ + { "restart", no_argument, &restart, 1 }, + +static uintptr_t vdso_addr; + +static int +handle_restart (void) +{ + fprintf (stderr, "vdso: %" PRIxPTR "\n", vdso_addr); + return 0; +} + +static unsigned long int +parse_address (const char *str) +{ + char *endptr; + long int ret; + errno = 0; + ret = strtol (str, &endptr, 10); + TEST_COMPARE (errno, 0); + TEST_VERIFY (ret >= 0 && ret <= INT_MAX); + return ret; +} + +static inline bool +startswith (const char *str, const char *pre) +{ + size_t lenpre = strlen (pre); + size_t lenstr = strlen (str); + return lenstr < lenpre ? false : memcmp (pre, str, lenpre) == 0; +} + +static int +do_test (int argc, char *argv[]) +{ + vdso_addr = getauxval (AT_SYSINFO_EHDR); + if (vdso_addr == 0) + FAIL_UNSUPPORTED ("getauxval (AT_SYSINFO_EHDR) returned 0"); + + /* We must have either: + - One our fource parameters left if called initially: + + path to ld.so optional + + "--library-path" optional + + the library path optional + + the application name */ + + if (restart) + return handle_restart (); + + + char *spargv[9]; + int i = 0; + for (; i < argc - 1; i++) + spargv[i] = argv[i + 1]; + spargv[i++] = (char *) "--direct"; + spargv[i++] = (char *) "--restart"; + spargv[i] = NULL; + + setenv ("LD_AUDIT", "tst-auditmod22.so", 0); + struct support_capture_subprocess result + = support_capture_subprogram (spargv[0], spargv); + support_capture_subprocess_check (&result, "tst-audit22", 0, sc_allow_stderr); + + unsigned long vdso_process = 0; + unsigned long vdso_audit = 0; + + FILE *out = fmemopen (result.err.buffer, result.err.length, "r"); + TEST_VERIFY (out != NULL); + char *buffer = NULL; + size_t buffer_length = 0; + while (xgetline (&buffer, &buffer_length, out)) + { + if (startswith (buffer, "vdso: ")) + vdso_process = parse_address (buffer + strlen ("vdso: ")); + else if (startswith (buffer, "vdso found: ")) + vdso_audit = parse_address (buffer + strlen ("vdso found: ")); + } + + TEST_COMPARE (vdso_process, vdso_audit); + + free (buffer); + xfclose (out); + + return 0; +} + +#define TEST_FUNCTION_ARGV do_test +#include <support/test-driver.c> diff --git a/elf/tst-auditmod22.c b/elf/tst-auditmod22.c new file mode 100644 index 0000000000..02275bed57 --- /dev/null +++ b/elf/tst-auditmod22.c @@ -0,0 +1,37 @@ +/* Check DTAUDIT and vDSO interaction. + Copyright (C) 2021 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 <link.h> +#include <inttypes.h> +#include <stdio.h> +#include <sys/auxv.h> + +unsigned int +la_version (unsigned int version) +{ + return LAV_CURRENT; +} + +unsigned int +la_objopen (struct link_map *map, Lmid_t lmid, uintptr_t *cookie) +{ + if (map->l_addr == getauxval (AT_SYSINFO_EHDR)) + fprintf (stderr, "vdso found: %" PRIxPTR "\n", (uintptr_t) map->l_addr); + + return 0; +} diff --git a/include/dlfcn.h b/include/dlfcn.h index a4c283728f..66bcf2dff9 100644 --- a/include/dlfcn.h +++ b/include/dlfcn.h @@ -12,6 +12,7 @@ #define __RTLD_AUDIT 0x08000000 #define __RTLD_SECURE 0x04000000 /* Apply additional security checks. */ #define __RTLD_NOIFUNC 0x02000000 /* Suppress calling ifunc functions. */ +#define __RTLD_VDSO 0x01000000 #define __LM_ID_CALLER -2
next reply other threads:[~2021-11-09 18:19 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-09 18:19 Adhemerval Zanella [this message] -- strict thread matches above, loose matches on Subject: below -- 2021-11-16 13:58 Adhemerval Zanella 2021-09-10 18:26 Adhemerval Zanella 2021-08-04 20:53 Adhemerval Zanella 2021-08-04 17:47 Adhemerval Zanella 2021-07-30 19:25 Adhemerval Zanella
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20211109181911.66079385841C@sourceware.org \ --to=azanella@sourceware.org \ --cc=glibc-cvs@sourceware.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).