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Revert "Linux: Consolidate auxiliary vector parsing"

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This reverts commit 8c8510ab27.  The
revert is not perfect because the commit included a bug fix for
_dl_sysdep_start with an empty argv, introduced in commit
2d47fa6862 ("Linux: Remove
DL_FIND_ARG_COMPONENTS"), and this bug fix is kept.

The revert is necessary because the reverted commit introduced an
early memset call on aarch64, which leads to crash due to lack of TCB
initialization.

(cherry picked from commit d96d2995c1)
This commit is contained in:
Florian Weimer 2022-02-11 16:01:19 +01:00
parent 4b9cd5465d
commit 1cc4ddfeeb
6 changed files with 180 additions and 106 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

80
elf/dl-support.c
View File

@ -239,21 +239,93 @@ __rtld_lock_define_initialized_recursive (, _dl_load_tls_lock)
#ifdef HAVE_AUX_VECTOR
#include <dl-parse_auxv.h>
int _dl_clktck;
void
_dl_aux_init (ElfW(auxv_t) *av)
{
int seen = 0;
uid_t uid = 0;
gid_t gid = 0;
#ifdef NEED_DL_SYSINFO
/* NB: Avoid RELATIVE relocation in static PIE. */
GL(dl_sysinfo) = DL_SYSINFO_DEFAULT;
#endif
_dl_auxv = av;
dl_parse_auxv_t auxv_values = { 0, };
_dl_parse_auxv (av, auxv_values);
for (; av->a_type != AT_NULL; ++av)
switch (av->a_type)
{
case AT_PAGESZ:
if (av->a_un.a_val != 0)
GLRO(dl_pagesize) = av->a_un.a_val;
break;
case AT_CLKTCK:
GLRO(dl_clktck) = av->a_un.a_val;
break;
case AT_PHDR:
GL(dl_phdr) = (const void *) av->a_un.a_val;
break;
case AT_PHNUM:
GL(dl_phnum) = av->a_un.a_val;
break;
case AT_PLATFORM:
GLRO(dl_platform) = (void *) av->a_un.a_val;
break;
case AT_HWCAP:
GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
break;
case AT_HWCAP2:
GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
break;
case AT_FPUCW:
GLRO(dl_fpu_control) = av->a_un.a_val;
break;
#ifdef NEED_DL_SYSINFO
case AT_SYSINFO:
GL(dl_sysinfo) = av->a_un.a_val;
break;
#endif
#ifdef NEED_DL_SYSINFO_DSO
case AT_SYSINFO_EHDR:
GL(dl_sysinfo_dso) = (void *) av->a_un.a_val;
break;
#endif
case AT_UID:
uid ^= av->a_un.a_val;
seen |= 1;
break;
case AT_EUID:
uid ^= av->a_un.a_val;
seen |= 2;
break;
case AT_GID:
gid ^= av->a_un.a_val;
seen |= 4;
break;
case AT_EGID:
gid ^= av->a_un.a_val;
seen |= 8;
break;
case AT_SECURE:
seen = -1;
__libc_enable_secure = av->a_un.a_val;
__libc_enable_secure_decided = 1;
break;
case AT_RANDOM:
_dl_random = (void *) av->a_un.a_val;
break;
case AT_MINSIGSTKSZ:
_dl_minsigstacksize = av->a_un.a_val;
break;
DL_PLATFORM_AUXV
}
if (seen == 0xf)
{
__libc_enable_secure = uid != 0 || gid != 0;
__libc_enable_secure_decided = 1;
}
}
#endif

18
sysdeps/unix/sysv/linux/alpha/dl-auxv.h
View File

@ -20,8 +20,16 @@
extern long __libc_alpha_cache_shape[4];
#define DL_PLATFORM_AUXV \
__libc_alpha_cache_shape[0] = auxv_values[AT_L1I_CACHESHAPE]; \
__libc_alpha_cache_shape[1] = auxv_values[AT_L1D_CACHESHAPE]; \
__libc_alpha_cache_shape[2] = auxv_values[AT_L2_CACHESHAPE]; \
__libc_alpha_cache_shape[3] = auxv_values[AT_L3_CACHESHAPE];
#define DL_PLATFORM_AUXV \
case AT_L1I_CACHESHAPE: \
__libc_alpha_cache_shape[0] = av->a_un.a_val; \
break; \
case AT_L1D_CACHESHAPE: \
__libc_alpha_cache_shape[1] = av->a_un.a_val; \
break; \
case AT_L2_CACHESHAPE: \
__libc_alpha_cache_shape[2] = av->a_un.a_val; \
break; \
case AT_L3_CACHESHAPE: \
__libc_alpha_cache_shape[3] = av->a_un.a_val; \
break;

61
sysdeps/unix/sysv/linux/dl-parse_auxv.h
View File

@ -1,61 +0,0 @@
/* Parse the Linux auxiliary vector.
Copyright (C) 1995-2022 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 <elf.h>
#include <entry.h>
#include <fpu_control.h>
#include <ldsodefs.h>
#include <link.h>
typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1];
/* Copy the auxiliary vector into AUX_VALUES and set up GLRO
variables. */
static inline
void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values)
{
auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT;
auxv_values[AT_PAGESZ] = EXEC_PAGESIZE;
auxv_values[AT_FPUCW] = _FPU_DEFAULT;
/* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */
_Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
"CONSTANT_MINSIGSTKSZ is constant");
auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ;
for (; av->a_type != AT_NULL; av++)
if (av->a_type <= AT_MINSIGSTKSZ)
auxv_values[av->a_type] = av->a_un.a_val;
GLRO(dl_pagesize) = auxv_values[AT_PAGESZ];
__libc_enable_secure = auxv_values[AT_SECURE];
GLRO(dl_platform) = (void *) auxv_values[AT_PLATFORM];
GLRO(dl_hwcap) = auxv_values[AT_HWCAP];
GLRO(dl_hwcap2) = auxv_values[AT_HWCAP2];
GLRO(dl_clktck) = auxv_values[AT_CLKTCK];
GLRO(dl_fpu_control) = auxv_values[AT_FPUCW];
_dl_random = (void *) auxv_values[AT_RANDOM];
GLRO(dl_minsigstacksize) = auxv_values[AT_MINSIGSTKSZ];
GLRO(dl_sysinfo_dso) = (void *) auxv_values[AT_SYSINFO_EHDR];
#ifdef NEED_DL_SYSINFO
if (GLRO(dl_sysinfo_dso) != NULL)
GLRO(dl_sysinfo) = auxv_values[AT_SYSINFO];
#endif
DL_PLATFORM_AUXV
}

109
sysdeps/unix/sysv/linux/dl-sysdep.c
View File

@ -21,12 +21,13 @@
#include <dl-auxv.h>
#include <dl-hwcap-check.h>
#include <dl-osinfo.h>
#include <dl-parse_auxv.h>
#include <dl-procinfo.h>
#include <dl-tunables.h>
#include <elf.h>
#include <entry.h>
#include <errno.h>
#include <fcntl.h>
#include <fpu_control.h>
#include <ldsodefs.h>
#include <libc-internal.h>
#include <libintl.h>
@ -62,20 +63,20 @@ void *_dl_random attribute_relro = NULL;
# define DL_STACK_END(cookie) ((void *) (cookie))
#endif
/* Arguments passed to dl_main. */
struct dl_main_arguments
ElfW(Addr)
_dl_sysdep_start (void **start_argptr,
void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
{
const ElfW(Phdr) *phdr;
ElfW(Word) phnum;
const ElfW(Phdr) *phdr = NULL;
ElfW(Word) phnum = 0;
ElfW(Addr) user_entry;
};
ElfW(auxv_t) *av;
#ifdef NEED_DL_SYSINFO
uintptr_t new_sysinfo = 0;
#endif
/* Separate function, so that dl_main can be called without the large
array on the stack. */
static void
_dl_sysdep_parse_arguments (void **start_argptr,
struct dl_main_arguments *args)
{
__libc_stack_end = DL_STACK_END (start_argptr);
_dl_argc = (intptr_t) *start_argptr;
_dl_argv = (char **) (start_argptr + 1); /* Necessary aliasing violation. */
_environ = _dl_argv + _dl_argc + 1;
@ -87,26 +88,75 @@ _dl_sysdep_parse_arguments (void **start_argptr,
break;
}
dl_parse_auxv_t auxv_values = { 0, };
_dl_parse_auxv (GLRO(dl_auxv), auxv_values);
user_entry = (ElfW(Addr)) ENTRY_POINT;
GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */
args->phdr = (const ElfW(Phdr) *) auxv_values[AT_PHDR];
args->phnum = auxv_values[AT_PHNUM];
args->user_entry = auxv_values[AT_ENTRY];
}
/* NB: Default to a constant CONSTANT_MINSIGSTKSZ. */
_Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
"CONSTANT_MINSIGSTKSZ is constant");
GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ;
ElfW(Addr)
_dl_sysdep_start (void **start_argptr,
void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
{
__libc_stack_end = DL_STACK_END (start_argptr);
struct dl_main_arguments dl_main_args;
_dl_sysdep_parse_arguments (start_argptr, &dl_main_args);
for (av = GLRO(dl_auxv); av->a_type != AT_NULL; av++)
switch (av->a_type)
{
case AT_PHDR:
phdr = (void *) av->a_un.a_val;
break;
case AT_PHNUM:
phnum = av->a_un.a_val;
break;
case AT_PAGESZ:
GLRO(dl_pagesize) = av->a_un.a_val;
break;
case AT_ENTRY:
user_entry = av->a_un.a_val;
break;
case AT_SECURE:
__libc_enable_secure = av->a_un.a_val;
break;
case AT_PLATFORM:
GLRO(dl_platform) = (void *) av->a_un.a_val;
break;
case AT_HWCAP:
GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
break;
case AT_HWCAP2:
GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
break;
case AT_CLKTCK:
GLRO(dl_clktck) = av->a_un.a_val;
break;
case AT_FPUCW:
GLRO(dl_fpu_control) = av->a_un.a_val;
break;
#ifdef NEED_DL_SYSINFO
case AT_SYSINFO:
new_sysinfo = av->a_un.a_val;
break;
#endif
case AT_SYSINFO_EHDR:
GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
break;
case AT_RANDOM:
_dl_random = (void *) av->a_un.a_val;
break;
case AT_MINSIGSTKSZ:
GLRO(dl_minsigstacksize) = av->a_un.a_val;
break;
DL_PLATFORM_AUXV
}
dl_hwcap_check ();
#ifdef NEED_DL_SYSINFO
if (new_sysinfo != 0)
{
/* Only set the sysinfo value if we also have the vsyscall DSO. */
if (GLRO(dl_sysinfo_dso) != 0)
GLRO(dl_sysinfo) = new_sysinfo;
}
#endif
__tunables_init (_environ);
__brk (0); /* Initialize the break. */
@ -134,9 +184,8 @@ _dl_sysdep_start (void **start_argptr,
if (__builtin_expect (__libc_enable_secure, 0))
__libc_check_standard_fds ();
(*dl_main) (dl_main_args.phdr, dl_main_args.phnum,
&dl_main_args.user_entry, GLRO(dl_auxv));
return dl_main_args.user_entry;
(*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv));
return user_entry;
}
void

14
sysdeps/unix/sysv/linux/powerpc/dl-auxv.h
View File

@ -16,5 +16,15 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#define DL_PLATFORM_AUXV \
GLRO(dl_cache_line_size) = auxv_values[AT_DCACHEBSIZE];
#include <ldsodefs.h>
#if IS_IN (libc) && !defined SHARED
int GLRO(dl_cache_line_size);
#endif
/* Scan the Aux Vector for the "Data Cache Block Size" entry and assign it
to dl_cache_line_size. */
#define DL_PLATFORM_AUXV \
case AT_DCACHEBSIZE: \
GLRO(dl_cache_line_size) = av->a_un.a_val; \
break;

4
sysdeps/unix/sysv/linux/powerpc/dl-support.c
View File

@ -1,4 +0,0 @@
#include <elf/dl-support.c>
/* Populated from the auxiliary vector. */
int _dl_cache_line_size;