forked from rpms/glibc
315 lines
10 KiB
Diff
315 lines
10 KiB
Diff
commit d1b9bee29a1c4e0b80db53f228e22550c3604894
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Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Date: Mon Jul 19 18:42:26 2021 -0300
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elf: Issue audit la_objopen for vDSO
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The vDSO is is listed in the link_map chain, but is never the subject of
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an la_objopen call. A new internal flag __RTLD_VDSO is added that
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acts as __RTLD_OPENEXEC to allocate the required 'struct auditstate'
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extra space for the 'struct link_map'.
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The return value from the callback is currently ignored, since there
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is no PLT call involved by glibc when using the vDSO, neither the vDSO
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are exported directly.
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Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
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Reviewed-by: Florian Weimer <fweimer@redhat.com>
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(cherry picked from commit f0e23d34a7bdf6b90fba954ee741419171ac41b2)
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Resolved conflicts:
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elf/Makefile
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diff --git a/elf/Makefile b/elf/Makefile
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index 29f545d2272bf6e2..465442bf59fa9794 100644
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--- a/elf/Makefile
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+++ b/elf/Makefile
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@@ -366,6 +366,7 @@ tests += \
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tst-audit17 \
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tst-audit18 \
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tst-audit19b \
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+ tst-audit22 \
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tst-auditmany \
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tst-auxobj \
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tst-auxobj-dlopen \
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@@ -649,6 +650,7 @@ modules-names = \
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tst-auditmod18 \
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tst-auditmod19a \
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tst-auditmod19b \
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+ tst-auditmod22 \
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tst-auxvalmod \
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tst-big-note-lib \
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tst-deep1mod1 \
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@@ -2035,6 +2037,9 @@ $(objpfx)tst-audit19b.out: $(objpfx)tst-auditmod19b.so
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$(objpfx)tst-audit19b: $(objpfx)tst-audit19bmod.so
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tst-audit19b-ARGS = -- $(host-test-program-cmd)
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+$(objpfx)tst-audit22.out: $(objpfx)tst-auditmod22.so
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+tst-audit22-ARGS = -- $(host-test-program-cmd)
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+
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# tst-sonamemove links against an older implementation of the library.
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LDFLAGS-tst-sonamemove-linkmod1.so = \
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-Wl,--version-script=tst-sonamemove-linkmod1.map \
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diff --git a/elf/dl-object.c b/elf/dl-object.c
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index 1875599eb274dc35..dee49a32d4fdf07d 100644
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--- a/elf/dl-object.c
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+++ b/elf/dl-object.c
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@@ -59,16 +59,19 @@ _dl_new_object (char *realname, const char *libname, int type,
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{
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#ifdef SHARED
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unsigned int naudit;
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- if (__glibc_unlikely ((mode & __RTLD_OPENEXEC) != 0))
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+ if (__glibc_unlikely ((mode & (__RTLD_OPENEXEC | __RTLD_VDSO)) != 0))
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{
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- assert (type == lt_executable);
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- assert (nsid == LM_ID_BASE);
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+ if (mode & __RTLD_OPENEXEC)
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+ {
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+ assert (type == lt_executable);
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+ assert (nsid == LM_ID_BASE);
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- /* Ignore the specified libname for the main executable. It is
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- only known with an explicit loader invocation. */
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- libname = "";
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+ /* Ignore the specified libname for the main executable. It is
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+ only known with an explicit loader invocation. */
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+ libname = "";
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+ }
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- /* We create the map for the executable before we know whether
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+ /* We create the map for the executable and vDSO before we know whether
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we have auditing libraries and if yes, how many. Assume the
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worst. */
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naudit = DL_NNS;
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diff --git a/elf/rtld.c b/elf/rtld.c
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index f632a767d7a269ef..b089e5cf4740443e 100644
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--- a/elf/rtld.c
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+++ b/elf/rtld.c
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@@ -1922,6 +1922,12 @@ dl_main (const ElfW(Phdr) *phdr,
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assert (i == npreloads);
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}
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+#ifdef NEED_DL_SYSINFO_DSO
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+ /* Now that the audit modules are opened, call la_objopen for the vDSO. */
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+ if (GLRO(dl_sysinfo_map) != NULL)
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+ _dl_audit_objopen (GLRO(dl_sysinfo_map), LM_ID_BASE);
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+#endif
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+
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/* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
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specified some libraries to load, these are inserted before the actual
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dependencies in the executable's searchlist for symbol resolution. */
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diff --git a/elf/setup-vdso.h b/elf/setup-vdso.h
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index 3f20578046de76ed..2b013d974a377a83 100644
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--- a/elf/setup-vdso.h
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+++ b/elf/setup-vdso.h
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@@ -30,7 +30,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
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We just want our data structures to describe it as if we had just
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mapped and relocated it normally. */
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struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL,
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- 0, LM_ID_BASE);
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+ __RTLD_VDSO, LM_ID_BASE);
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if (__glibc_likely (l != NULL))
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{
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l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)
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diff --git a/elf/tst-audit22.c b/elf/tst-audit22.c
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new file mode 100644
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index 0000000000000000..18fd22a760ddc3d8
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--- /dev/null
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+++ b/elf/tst-audit22.c
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@@ -0,0 +1,124 @@
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+/* Check DTAUDIT and vDSO interaction.
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+ Copyright (C) 2021 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <errno.h>
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+#include <getopt.h>
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+#include <limits.h>
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+#include <inttypes.h>
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+#include <string.h>
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+#include <stdlib.h>
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+#include <support/capture_subprocess.h>
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+#include <support/check.h>
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+#include <support/xstdio.h>
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+#include <support/support.h>
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+#include <sys/auxv.h>
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+
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+static int restart;
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+#define CMDLINE_OPTIONS \
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+ { "restart", no_argument, &restart, 1 },
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+
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+static uintptr_t vdso_addr;
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+
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+static int
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+handle_restart (void)
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+{
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+ fprintf (stderr, "vdso: %p\n", (void*) vdso_addr);
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+ return 0;
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+}
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+
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+static uintptr_t
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+parse_address (const char *str)
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+{
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+ void *r;
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+ TEST_COMPARE (sscanf (str, "%p\n", &r), 1);
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+ return (uintptr_t) r;
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+}
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+
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+static inline bool
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+startswith (const char *str, const char *pre)
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+{
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+ size_t lenpre = strlen (pre);
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+ size_t lenstr = strlen (str);
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+ return lenstr >= lenpre && memcmp (pre, str, lenpre) == 0;
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+}
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+
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+static int
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+do_test (int argc, char *argv[])
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+{
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+ vdso_addr = getauxval (AT_SYSINFO_EHDR);
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+ if (vdso_addr == 0)
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+ FAIL_UNSUPPORTED ("getauxval (AT_SYSINFO_EHDR) returned 0");
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+
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+ /* We must have either:
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+ - One our fource parameters left if called initially:
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+ + path to ld.so optional
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+ + "--library-path" optional
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+ + the library path optional
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+ + the application name */
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+ if (restart)
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+ return handle_restart ();
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+
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+ char *spargv[9];
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+ int i = 0;
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+ for (; i < argc - 1; i++)
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+ spargv[i] = argv[i + 1];
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+ spargv[i++] = (char *) "--direct";
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+ spargv[i++] = (char *) "--restart";
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+ spargv[i] = NULL;
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+
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+ setenv ("LD_AUDIT", "tst-auditmod22.so", 0);
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+ struct support_capture_subprocess result
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+ = support_capture_subprogram (spargv[0], spargv);
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+ support_capture_subprocess_check (&result, "tst-audit22", 0, sc_allow_stderr);
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+
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+ /* The respawned process should always print the vDSO address (otherwise it
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+ will fails as unsupported). However, on some architectures the audit
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+ module might see the vDSO with l_addr being 0, meaning a fixed mapping
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+ (linux-gate.so). In this case we don't check its value against
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+ AT_SYSINFO_EHDR one. */
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+ uintptr_t vdso_process = 0;
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+ bool vdso_audit_found = false;
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+ uintptr_t vdso_audit = 0;
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+
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+ FILE *out = fmemopen (result.err.buffer, result.err.length, "r");
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+ TEST_VERIFY (out != NULL);
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+ char *buffer = NULL;
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+ size_t buffer_length = 0;
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+ while (xgetline (&buffer, &buffer_length, out))
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+ {
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+ if (startswith (buffer, "vdso: "))
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+ vdso_process = parse_address (buffer + strlen ("vdso: "));
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+ else if (startswith (buffer, "vdso found: "))
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+ {
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+ vdso_audit = parse_address (buffer + strlen ("vdso found: "));
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+ vdso_audit_found = true;
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+ }
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+ }
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+
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+ TEST_COMPARE (vdso_audit_found, true);
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+ if (vdso_audit != 0)
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+ TEST_COMPARE (vdso_process, vdso_audit);
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+
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+ free (buffer);
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+ xfclose (out);
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+
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+ return 0;
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+}
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+
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+#define TEST_FUNCTION_ARGV do_test
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+#include <support/test-driver.c>
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diff --git a/elf/tst-auditmod22.c b/elf/tst-auditmod22.c
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new file mode 100644
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index 0000000000000000..8e05ce8cbb215dd5
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--- /dev/null
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+++ b/elf/tst-auditmod22.c
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@@ -0,0 +1,51 @@
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+/* Check DTAUDIT and vDSO interaction.
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+ Copyright (C) 2021 Free Software Foundation, Inc.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <link.h>
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+#include <inttypes.h>
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+#include <stdbool.h>
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+#include <string.h>
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+#include <stdio.h>
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+#include <sys/auxv.h>
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+
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+static inline bool
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+startswith (const char *str, const char *pre)
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+{
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+ size_t lenpre = strlen (pre);
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+ size_t lenstr = strlen (str);
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+ return lenstr < lenpre ? false : memcmp (pre, str, lenpre) == 0;
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+}
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+
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+unsigned int
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+la_version (unsigned int version)
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+{
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+ return LAV_CURRENT;
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+}
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+
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+unsigned int
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+la_objopen (struct link_map *map, Lmid_t lmid, uintptr_t *cookie)
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+{
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+ /* The linux-gate.so is placed at a fixed address, thus l_addr being 0,
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+ and it might be the value reported as the AT_SYSINFO_EHDR. */
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+ if (map->l_addr == 0 && startswith (map->l_name, "linux-gate.so"))
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+ fprintf (stderr, "vdso found: %p\n", NULL);
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+ else if (map->l_addr == getauxval (AT_SYSINFO_EHDR))
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+ fprintf (stderr, "vdso found: %p\n", (void*) map->l_addr);
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+
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+ return 0;
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+}
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diff --git a/include/dlfcn.h b/include/dlfcn.h
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index a4c283728f94deb4..e73294b0af587913 100644
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--- a/include/dlfcn.h
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+++ b/include/dlfcn.h
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@@ -12,6 +12,8 @@
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#define __RTLD_AUDIT 0x08000000
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#define __RTLD_SECURE 0x04000000 /* Apply additional security checks. */
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#define __RTLD_NOIFUNC 0x02000000 /* Suppress calling ifunc functions. */
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+#define __RTLD_VDSO 0x01000000 /* Tell _dl_new_object the object is
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+ system-loaded. */
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#define __LM_ID_CALLER -2
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