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elf: Fix elf_get_dynamic_info() for bootstrap

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THe d6d89608ac broke powerpc for --enable-bind-now because it turned
out that different than patch assumption rtld elf_get_dynamic_info()
does require to handle RTLD_BOOTSTRAP to avoid DT_FLAGS and
DT_RUNPATH (more specially the GLRO usage which is not reallocate
yet).

This patch fixes by passing two arguments to elf_get_dynamic_info()
to inform that by rtld (bootstrap) or static pie initialization
(static_pie_bootstrap).  I think using explicit argument is way more
clear and burried C preprocessor, and compiler should remove the
dead code.

I checked on x86_64 and i686 with default options, --enable-bind-now,
and --enable-bind-now and --enable--static-pie.  I also check on
aarch64, armhf, powerpc64, and powerpc with default and
--enable-bind-now.
This commit is contained in:
Adhemerval Zanella 2021-10-15 14:35:31 -03:00
parent 1d3decee99
commit 5118dcac68
5 changed files with 61 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
elf/dl-load.c
View File

@ -1298,7 +1298,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
else
l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr);
elf_get_dynamic_info (l);
elf_get_dynamic_info (l, false, false);
/* Make sure we are not dlopen'ing an object that has the
DF_1_NOOPEN flag set, or a PIE object. */

3
elf/dl-reloc-static-pie.c
View File

@ -25,7 +25,6 @@
#include <dl-machine.h>
#define STATIC_PIE_BOOTSTRAP
#define RESOLVE_MAP(map, scope, sym, version, flags) map
#include "dynamic-link.h"
#include "get-dynamic-info.h"
@ -52,7 +51,7 @@ _dl_relocate_static_pie (void)
break;
}
elf_get_dynamic_info (main_map);
elf_get_dynamic_info (main_map, false, true);
# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
ELF_MACHINE_BEFORE_RTLD_RELOC (main_map, main_map->l_info);

95
elf/get-dynamic-info.h
View File

@ -26,7 +26,8 @@
#include <libc-diag.h>
static inline void __attribute__ ((unused, always_inline))
elf_get_dynamic_info (struct link_map *l)
elf_get_dynamic_info (struct link_map *l, bool bootstrap,
bool static_pie_bootstrap)
{
#if __ELF_NATIVE_CLASS == 32
typedef Elf32_Word d_tag_utype;
@ -35,7 +36,7 @@ elf_get_dynamic_info (struct link_map *l)
#endif
#ifndef STATIC_PIE_BOOTSTRAP
if (l->l_ld == NULL)
if (!bootstrap && l->l_ld == NULL)
return;
#endif
@ -112,47 +113,63 @@ elf_get_dynamic_info (struct link_map *l)
if (info[DT_REL] != NULL)
assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
#endif
#ifdef STATIC_PIE_BOOTSTRAP
assert (info[DT_RUNPATH] == NULL);
assert (info[DT_RPATH] == NULL);
#endif
if (info[DT_FLAGS] != NULL)
if (bootstrap || static_pie_bootstrap)
{
/* Flags are used. Translate to the old form where available.
Since these l_info entries are only tested for NULL pointers it
is ok if they point to the DT_FLAGS entry. */
l->l_flags = info[DT_FLAGS]->d_un.d_val;
if (l->l_flags & DF_SYMBOLIC)
info[DT_SYMBOLIC] = info[DT_FLAGS];
if (l->l_flags & DF_TEXTREL)
info[DT_TEXTREL] = info[DT_FLAGS];
if (l->l_flags & DF_BIND_NOW)
info[DT_BIND_NOW] = info[DT_FLAGS];
assert (info[DT_RUNPATH] == NULL);
assert (info[DT_RPATH] == NULL);
}
if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
if (bootstrap)
{
l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
if (l->l_flags_1 & DF_1_NODELETE)
l->l_nodelete_pending = true;
/* Only DT_1_SUPPORTED_MASK bits are supported, and we would like
to assert this, but we can't. Users have been setting
unsupported DF_1_* flags for a long time and glibc has ignored
them. Therefore to avoid breaking existing applications the
best we can do is add a warning during debugging with the
intent of notifying the user of the problem. */
if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0)
&& l->l_flags_1 & ~DT_1_SUPPORTED_MASK)
_dl_debug_printf ("\nWARNING: Unsupported flag value(s) of 0x%x in DT_FLAGS_1.\n",
l->l_flags_1 & ~DT_1_SUPPORTED_MASK);
if (l->l_flags_1 & DF_1_NOW)
info[DT_BIND_NOW] = info[VERSYMIDX (DT_FLAGS_1)];
/* Only the bind now flags are allowed. */
assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
|| (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
/* Flags must not be set for ld.so. */
assert (info[DT_FLAGS] == NULL
|| (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
}
if (info[DT_RUNPATH] != NULL)
/* If both RUNPATH and RPATH are given, the latter is ignored. */
info[DT_RPATH] = NULL;
else
{
if (info[DT_FLAGS] != NULL)
{
/* Flags are used. Translate to the old form where available.
Since these l_info entries are only tested for NULL pointers it
is ok if they point to the DT_FLAGS entry. */
l->l_flags = info[DT_FLAGS]->d_un.d_val;
if (l->l_flags & DF_SYMBOLIC)
info[DT_SYMBOLIC] = info[DT_FLAGS];
if (l->l_flags & DF_TEXTREL)
info[DT_TEXTREL] = info[DT_FLAGS];
if (l->l_flags & DF_BIND_NOW)
info[DT_BIND_NOW] = info[DT_FLAGS];
}
if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
{
l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
if (l->l_flags_1 & DF_1_NODELETE)
l->l_nodelete_pending = true;
/* Only DT_1_SUPPORTED_MASK bits are supported, and we would like
to assert this, but we can't. Users have been setting
unsupported DF_1_* flags for a long time and glibc has ignored
them. Therefore to avoid breaking existing applications the
best we can do is add a warning during debugging with the
intent of notifying the user of the problem. */
if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0)
&& l->l_flags_1 & ~DT_1_SUPPORTED_MASK)
_dl_debug_printf ("\nWARNING: Unsupported flag value(s) of 0x%x "
"in DT_FLAGS_1.\n",
l->l_flags_1 & ~DT_1_SUPPORTED_MASK);
if (l->l_flags_1 & DF_1_NOW)
info[DT_BIND_NOW] = info[VERSYMIDX (DT_FLAGS_1)];
}
if (info[DT_RUNPATH] != NULL)
/* If both RUNPATH and RPATH are given, the latter is ignored. */
info[DT_RPATH] = NULL;
}
}
#endif

4
elf/rtld.c
View File

@ -547,7 +547,7 @@ _dl_start (void *arg)
/* Read our own dynamic section and fill in the info array. */
bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
elf_get_dynamic_info (&bootstrap_map);
elf_get_dynamic_info (&bootstrap_map, true, false);
#if NO_TLS_OFFSET != 0
bootstrap_map.l_tls_offset = NO_TLS_OFFSET;
@ -1615,7 +1615,7 @@ dl_main (const ElfW(Phdr) *phdr,
if (! rtld_is_main)
{
/* Extract the contents of the dynamic section for easy access. */
elf_get_dynamic_info (main_map);
elf_get_dynamic_info (main_map, false, false);
/* If the main map is libc.so, update the base namespace to
refer to this map. If libc.so is loaded later, this happens

2
elf/setup-vdso.h
View File

@ -64,7 +64,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
l->l_map_end += l->l_addr;
l->l_text_end += l->l_addr;
l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
elf_get_dynamic_info (l);
elf_get_dynamic_info (l, false, false);
_dl_setup_hash (l);
l->l_relocated = 1;