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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2019-11-29 10:44:59 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2020-01-03 11:22:07 -0300
commit1bdda52fe92fd01b424cd6fbb63e3df96a95015c (patch)
treed25214e63bf5c96ab48c11ec0df28b5d96ca99da /elf
parent57013650f7e796428ac2c0b7512757e99327bfc9 (diff)
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elf: Move vDSO setup to rtld (BZ#24967)
This patch moves the vDSO setup from libc to loader code, just after the vDSO link_map setup. For static case the initialization is moved to _dl_non_dynamic_init instead. Instead of using the mangled pointer, the vDSO data is set as attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for static). It is read-only even with partial relro. It fixes BZ#24967 now that the vDSO pointer is setup earlier than malloc interposition is called. Also, vDSO calls should not be a problem for static dlopen as indicated by BZ#20802. The vDSO pointer would be zero-initialized and the syscall will be issued instead. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and sparcv9-linux-gnu. I also run some tests on mips. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Diffstat (limited to 'elf')
-rw-r--r--elf/dl-support.c7
-rw-r--r--elf/rtld.c7
2 files changed, 13 insertions, 1 deletions
diff --git a/elf/dl-support.c b/elf/dl-support.c
index 508a5c1..ad791ab 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -34,6 +34,8 @@
#include <unsecvars.h>
#include <hp-timing.h>
#include <stackinfo.h>
+#include <dl-vdso.h>
+#include <dl-vdso-setup.h>
extern char *__progname;
char **_dl_argv = &__progname; /* This is checked for some error messages. */
@@ -201,6 +203,8 @@ struct link_map *_dl_sysinfo_map;
# include "get-dynamic-info.h"
#endif
#include "setup-vdso.h"
+/* Define the vDSO function pointers. */
+#include <dl-vdso-setup.c>
/* During the program run we must not modify the global data of
loaded shared object simultanously in two threads. Therefore we
@@ -315,6 +319,9 @@ _dl_non_dynamic_init (void)
so they can influence _dl_init_paths. */
setup_vdso (NULL, NULL);
+ /* With vDSO setup we can initialize the function pointers. */
+ setup_vdso_pointers ();
+
/* Initialize the data structures for the search paths for shared
objects. */
_dl_init_paths (getenv ("LD_LIBRARY_PATH"));
diff --git a/elf/rtld.c b/elf/rtld.c
index 817fb86..553cfbd 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -39,6 +39,8 @@
#include <dl-osinfo.h>
#include <dl-procinfo.h>
#include <dl-prop.h>
+#include <dl-vdso.h>
+#include <dl-vdso-setup.h>
#include <tls.h>
#include <stap-probe.h>
#include <stackinfo.h>
@@ -833,7 +835,7 @@ security_init (void)
_dl_random = NULL;
}
-#include "setup-vdso.h"
+#include <setup-vdso.h>
/* The library search path. */
static const char *library_path attribute_relro;
@@ -1538,6 +1540,9 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
so they can influence _dl_init_paths. */
setup_vdso (main_map, &first_preload);
+ /* With vDSO setup we can initialize the function pointers. */
+ setup_vdso_pointers ();
+
#ifdef DL_SYSDEP_OSCHECK
DL_SYSDEP_OSCHECK (_dl_fatal_printf);
#endif