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>
2019-11-29 13:44:59 +00:00
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/* Data for vDSO support. Linux version.
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Copyright (C) 2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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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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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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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/* This file is included in three different modes for both static (libc.a)
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and shared (rtld) modes:
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1. PROCINFO_DECL is defined, meaning we are only interested in
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declarations. For static it requires use the extern keywork along with
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the attribute_relro while for shared it will be embedded in the
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rtld_global_ro.
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2. PROCINFO_DECL and SHARED are not defined. Nothing to do, the default
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zero initializion is suffice.
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3. PROCINFO_DECL is not defined while SHARED is. Similar to 2., the zero
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initialization of rtld_global_ro is suffice. */
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#ifndef PROCINFO_CLASS
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# define PROCINFO_CLASS
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#endif
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#ifndef SHARED
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# define RELRO attribute_relro
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#else
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# define RELRO
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#endif
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#if defined PROCINFO_DECL || !defined SHARED
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# ifdef HAVE_CLOCK_GETTIME_VSYSCALL
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PROCINFO_CLASS int (*_dl_vdso_clock_gettime) (clockid_t,
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struct timespec *) RELRO;
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#endif
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2019-12-11 14:13:50 +00:00
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# ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
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PROCINFO_CLASS int (*_dl_vdso_clock_gettime64) (clockid_t,
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struct __timespec64 *) RELRO;
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#endif
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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>
2019-11-29 13:44:59 +00:00
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# ifdef HAVE_GETTIMEOFDAY_VSYSCALL
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PROCINFO_CLASS int (*_dl_vdso_gettimeofday) (struct timeval *, void *) RELRO;
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#endif
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# ifdef HAVE_TIME_VSYSCALL
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PROCINFO_CLASS time_t (*_dl_vdso_time) (time_t *) RELRO;
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# endif
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# ifdef HAVE_GETCPU_VSYSCALL
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PROCINFO_CLASS int (*_dl_vdso_getcpu) (unsigned *, unsigned *, void *) RELRO;
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# endif
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# ifdef HAVE_CLOCK_GETRES_VSYSCALL
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PROCINFO_CLASS int (*_dl_vdso_clock_getres) (clockid_t,
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struct timespec *) RELRO;
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# endif
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/* PowerPC specific ones. */
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# ifdef HAVE_GET_TBFREQ
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PROCINFO_CLASS uint64_t (*_dl_vdso_get_tbfreq)(void) RELRO;
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# endif
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/* The sigtramp are used on powerpc backtrace without using
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INLINE_VSYSCALL, so there is no need to set their type. */
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# ifdef HAVE_SIGTRAMP_RT64
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PROCINFO_CLASS void *_dl_vdso_sigtramp_rt64 RELRO;
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# endif
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# ifdef HAVE_SIGTRAMP_RT32
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PROCINFO_CLASS void *_dl_vdso_sigtramp_rt32 RELRO;
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# endif
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# ifdef HAVE_SIGTRAMP_32
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PROCINFO_CLASS void *_dl_vdso_sigtramp_32 RELRO;
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# endif
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#endif
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#undef RELRO
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#undef PROCINFO_DECL
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#undef PROCINFO_CLASS
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