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elf: Move vDSO setup to rtld (BZ#24967)

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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>
This commit is contained in:
Adhemerval Zanella
2019-11-29 10:44:59 -03:00
parent 57013650f7
commit 1bdda52fe9
31 changed files with 258 additions and 290 deletions
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5
malloc/tst-interpose-aux.c
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@ -28,6 +28,7 @@
#include <sys/mman.h>
#include <sys/uio.h>
#include <unistd.h>
#include <time.h>
#if INTERPOSE_THREADS
#include <pthread.h>
@ -96,6 +97,7 @@ struct __attribute__ ((aligned (__alignof__ (max_align_t)))) allocation_header
{
size_t allocation_index;
size_t allocation_size;
struct timespec ts;
};
/* Array of known allocations, to track invalid frees. */
@ -166,6 +168,9 @@ malloc_internal (size_t size)
.allocation_index = index,
.allocation_size = allocation_size
};
/* BZ#24967: Check if calling a symbol which may use the vDSO does not fail.
The CLOCK_REALTIME should be supported on all systems. */
clock_gettime (CLOCK_REALTIME, &allocations[index]->ts);
return allocations[index] + 1;
}