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ld.so: Replace DL_RO_DYN_SECTION with dl_relocate_ld [BZ #28340]
We can't relocate entries in dynamic section if it is readonly: 1. Add a l_ld_readonly field to struct link_map to indicate if dynamic section is readonly and set it based on p_flags of PT_DYNAMIC segment. 2. Replace DL_RO_DYN_SECTION with dl_relocate_ld to decide if dynamic section should be relocated. 3. Remove DL_RO_DYN_TEMP_CNT. 4. Don't use a static dynamic section to make readonly dynamic section in vDSO writable. 5. Remove the temp argument from elf_get_dynamic_info. This fixes BZ #28340. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This commit is contained in:
parent
4eff749e8f
commit
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11
elf/Makefile
11
elf/Makefile
@ -224,7 +224,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
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tst-tls-ie tst-tls-ie-dlmopen argv0test \
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tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
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tst-tls20 tst-tls21 tst-dlmopen-dlerror tst-dlmopen-gethostbyname \
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tst-dl-is_dso
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tst-dl-is_dso tst-ro-dynamic
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# reldep9
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tests-internal += loadtest unload unload2 circleload1 \
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neededtest neededtest2 neededtest3 neededtest4 \
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@ -360,7 +360,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
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libmarkermod4-1 libmarkermod4-2 libmarkermod4-3 libmarkermod4-4 \
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tst-tls20mod-bad tst-tls21mod tst-dlmopen-dlerror-mod \
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tst-auxvalmod \
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tst-dlmopen-gethostbyname-mod \
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tst-dlmopen-gethostbyname-mod tst-ro-dynamic-mod \
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# Most modules build with _ISOMAC defined, but those filtered out
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# depend on internal headers.
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@ -1911,3 +1911,10 @@ $(objpfx)tst-getauxval-static.out: $(objpfx)tst-auxvalmod.so
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tst-getauxval-static-ENV = LD_LIBRARY_PATH=$(objpfx):$(common-objpfx)
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$(objpfx)tst-dlmopen-gethostbyname.out: $(objpfx)tst-dlmopen-gethostbyname-mod.so
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$(objpfx)tst-ro-dynamic: $(objpfx)tst-ro-dynamic-mod.so
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$(objpfx)tst-ro-dynamic-mod.so: $(objpfx)tst-ro-dynamic-mod.os \
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tst-ro-dynamic-mod.map
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$(LINK.o) -nostdlib -nostartfiles -shared -o $@ \
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-Wl,--script=tst-ro-dynamic-mod.map \
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$(objpfx)tst-ro-dynamic-mod.os
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@ -1149,6 +1149,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
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such a segment to avoid a crash later. */
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l->l_ld = (void *) ph->p_vaddr;
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l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
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l->l_ld_readonly = (ph->p_flags & PF_W) == 0;
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}
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break;
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@ -1292,7 +1293,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
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else
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l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr);
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elf_get_dynamic_info (l, NULL);
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elf_get_dynamic_info (l);
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/* Make sure we are not dlopen'ing an object that has the
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DF_1_NOOPEN flag set, or a PIE object. */
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@ -40,7 +40,17 @@ _dl_relocate_static_pie (void)
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/* Read our own dynamic section and fill in the info array. */
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main_map->l_ld = ((void *) main_map->l_addr + elf_machine_dynamic ());
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elf_get_dynamic_info (main_map, NULL);
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const ElfW(Phdr) *ph, *phdr = GL(dl_phdr);
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size_t phnum = GL(dl_phnum);
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for (ph = phdr; ph < &phdr[phnum]; ++ph)
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if (ph->p_type == PT_DYNAMIC)
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{
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main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
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break;
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}
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elf_get_dynamic_info (main_map);
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# ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
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ELF_MACHINE_BEFORE_RTLD_RELOC (main_map->l_info);
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@ -28,7 +28,7 @@ static
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auto
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#endif
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inline void __attribute__ ((unused, always_inline))
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elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
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elf_get_dynamic_info (struct link_map *l)
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{
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#if __ELF_NATIVE_CLASS == 32
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typedef Elf32_Word d_tag_utype;
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@ -69,28 +69,15 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
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info[i] = dyn;
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}
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#define DL_RO_DYN_TEMP_CNT 8
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#ifndef DL_RO_DYN_SECTION
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/* Don't adjust .dynamic unnecessarily. */
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if (l->l_addr != 0)
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if (l->l_addr != 0 && dl_relocate_ld (l))
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{
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ElfW(Addr) l_addr = l->l_addr;
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int cnt = 0;
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# define ADJUST_DYN_INFO(tag) \
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do \
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if (info[tag] != NULL) \
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{ \
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if (temp) \
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{ \
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temp[cnt].d_tag = info[tag]->d_tag; \
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temp[cnt].d_un.d_ptr = info[tag]->d_un.d_ptr + l_addr; \
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info[tag] = temp + cnt++; \
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} \
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else \
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info[tag]->d_un.d_ptr += l_addr; \
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} \
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info[tag]->d_un.d_ptr += l_addr; \
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while (0)
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ADJUST_DYN_INFO (DT_HASH);
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@ -107,9 +94,7 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
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ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
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ADJUST_DYN_INFO (ADDRIDX (DT_GNU_HASH));
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# undef ADJUST_DYN_INFO
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assert (cnt <= DL_RO_DYN_TEMP_CNT);
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}
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#endif
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if (info[DT_PLTREL] != NULL)
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{
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#if ELF_MACHINE_NO_RELA
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@ -463,6 +463,7 @@ _dl_start_final (void *arg, struct dl_start_final_info *info)
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#ifndef DONT_USE_BOOTSTRAP_MAP
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GL(dl_rtld_map).l_addr = info->l.l_addr;
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GL(dl_rtld_map).l_ld = info->l.l_ld;
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GL(dl_rtld_map).l_ld_readonly = info->l.l_ld_readonly;
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memcpy (GL(dl_rtld_map).l_info, info->l.l_info,
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sizeof GL(dl_rtld_map).l_info);
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GL(dl_rtld_map).l_mach = info->l.l_mach;
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@ -546,7 +547,7 @@ _dl_start (void *arg)
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/* Read our own dynamic section and fill in the info array. */
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bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
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elf_get_dynamic_info (&bootstrap_map, NULL);
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elf_get_dynamic_info (&bootstrap_map);
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#if NO_TLS_OFFSET != 0
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bootstrap_map.l_tls_offset = NO_TLS_OFFSET;
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@ -1468,6 +1469,7 @@ dl_main (const ElfW(Phdr) *phdr,
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/* This tells us where to find the dynamic section,
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which tells us everything we need to do. */
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main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
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main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
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break;
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case PT_INTERP:
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/* This "interpreter segment" was used by the program loader to
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@ -1613,7 +1615,7 @@ dl_main (const ElfW(Phdr) *phdr,
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if (! rtld_is_main)
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{
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/* Extract the contents of the dynamic section for easy access. */
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elf_get_dynamic_info (main_map, NULL);
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elf_get_dynamic_info (main_map);
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/* If the main map is libc.so, update the base namespace to
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refer to this map. If libc.so is loaded later, this happens
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@ -33,8 +33,6 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
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0, LM_ID_BASE);
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if (__glibc_likely (l != NULL))
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{
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static ElfW(Dyn) dyn_temp[DL_RO_DYN_TEMP_CNT] attribute_relro;
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l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)
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+ GLRO(dl_sysinfo_dso)->e_phoff);
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l->l_phnum = GLRO(dl_sysinfo_dso)->e_phnum;
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@ -45,6 +43,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
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{
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l->l_ld = (void *) ph->p_vaddr;
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l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
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l->l_ld_readonly = (ph->p_flags & PF_W) == 0;
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}
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else if (ph->p_type == PT_LOAD)
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{
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@ -65,7 +64,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
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l->l_map_end += l->l_addr;
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l->l_text_end += l->l_addr;
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l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
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elf_get_dynamic_info (l, dyn_temp);
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elf_get_dynamic_info (l);
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_dl_setup_hash (l);
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l->l_relocated = 1;
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19
elf/tst-ro-dynamic-mod.c
Normal file
19
elf/tst-ro-dynamic-mod.c
Normal file
@ -0,0 +1,19 @@
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/* Test case for DSO with readonly dynamic section.
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Copyright (C) 2021 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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int foo = -1;
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16
elf/tst-ro-dynamic-mod.map
Normal file
16
elf/tst-ro-dynamic-mod.map
Normal file
@ -0,0 +1,16 @@
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SECTIONS
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{
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. = SIZEOF_HEADERS;
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.dynamic : { *(.dynamic) } :text :dynamic
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.rodata : { *(.data*) *(.bss*) } :text
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/DISCARD/ : {
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*(.note.gnu.property)
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}
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.note : { *(.note.*) } :text :note
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}
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PHDRS
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{
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text PT_LOAD FLAGS(5) FILEHDR PHDRS;
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dynamic PT_DYNAMIC FLAGS(4);
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note PT_NOTE FLAGS(4);
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}
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31
elf/tst-ro-dynamic.c
Normal file
31
elf/tst-ro-dynamic.c
Normal file
@ -0,0 +1,31 @@
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/* Test case for DSO with readonly dynamic section.
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Copyright (C) 2021 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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#include <support/check.h>
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#include <support/test-driver.h>
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extern int foo;
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static int
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do_test (void)
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{
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TEST_COMPARE (foo, -1);
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return 0;
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}
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#include <support/test-driver.c>
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@ -205,6 +205,7 @@ struct link_map
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unsigned int l_free_initfini:1; /* Nonzero if l_initfini can be
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freed, ie. not allocated with
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the dummy malloc in ld.so. */
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unsigned int l_ld_readonly:1; /* Nonzero if dynamic section is readonly. */
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/* NODELETE status of the map. Only valid for maps of type
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lt_loaded. Lazy binding sets l_nodelete_active directly,
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@ -342,6 +343,8 @@ struct link_map
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unsigned long long int l_serial;
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};
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#include <dl-relocate-ld.h>
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/* Information used by audit modules. For most link maps, this data
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immediate follows the link map in memory. For the dynamic linker,
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it is allocated separately. See link_map_audit_state in
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|
32
sysdeps/generic/dl-relocate-ld.h
Normal file
32
sysdeps/generic/dl-relocate-ld.h
Normal file
@ -0,0 +1,32 @@
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/* Check if dynamic section should be relocated. Generic version.
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Copyright (C) 2021 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
|
||||
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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#ifndef _DL_RELOCATE_LD_H
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#define _DL_RELOCATE_LD_H
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/* Return true if dynamic section in the shared library L should be
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relocated. */
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static inline bool
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dl_relocate_ld (const struct link_map *l)
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{
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/* Don't relocate dynamic section if it is readonly */
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return !l->l_ld_readonly;
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}
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#endif /* _DL_RELOCATE_LD_H */
|
@ -75,11 +75,8 @@ __BEGIN_DECLS
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have to be accessed via the D_PTR macro. The macro is needed since for
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most architectures the entry is already relocated - but for some not
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and we need to relocate at access time. */
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#ifdef DL_RO_DYN_SECTION
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# define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
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#else
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# define D_PTR(map, i) (map)->i->d_un.d_ptr
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#endif
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#define D_PTR(map, i) \
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((map)->i->d_un.d_ptr + (dl_relocate_ld (map) ? 0 : (map)->l_addr))
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/* Result of the lookup functions and how to retrieve the base address. */
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typedef struct link_map *lookup_t;
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|
32
sysdeps/mips/dl-relocate-ld.h
Normal file
32
sysdeps/mips/dl-relocate-ld.h
Normal file
@ -0,0 +1,32 @@
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/* Check if dynamic section should be relocated. MIPS version.
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Copyright (C) 2021 Free Software Foundation, Inc.
|
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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/>. */
|
||||
|
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#ifndef _DL_RELOCATE_LD_H
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#define _DL_RELOCATE_LD_H
|
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|
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/* Return true if dynamic section in the shared library L should be
|
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relocated. */
|
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|
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static inline bool
|
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dl_relocate_ld (const struct link_map *l)
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{
|
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/* Never relocate dynamic section. */
|
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return false;
|
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}
|
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|
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#endif /* _DL_RELOCATE_LD_H */
|
@ -75,10 +75,6 @@ struct La_mips_64_retval;
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struct La_mips_64_retval *, \
|
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const char *);
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/* The MIPS ABI specifies that the dynamic section has to be read-only. */
|
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|
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#define DL_RO_DYN_SECTION 1
|
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|
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#include_next <ldsodefs.h>
|
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|
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/* The 64-bit MIPS ELF ABI uses an unusual reloc format. Each
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|
32
sysdeps/riscv/dl-relocate-ld.h
Normal file
32
sysdeps/riscv/dl-relocate-ld.h
Normal file
@ -0,0 +1,32 @@
|
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/* Check if dynamic section should be relocated. RISC-V version.
|
||||
Copyright (C) 2021 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/>. */
|
||||
|
||||
#ifndef _DL_RELOCATE_LD_H
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#define _DL_RELOCATE_LD_H
|
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|
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/* Return true if dynamic section in the shared library L should be
|
||||
relocated. */
|
||||
|
||||
static inline bool
|
||||
dl_relocate_ld (const struct link_map *l)
|
||||
{
|
||||
/* Never relocate dynamic section for ABI compatibility. */
|
||||
return false;
|
||||
}
|
||||
|
||||
#endif /* _DL_RELOCATE_LD_H */
|
@ -38,11 +38,6 @@ struct La_riscv_retval;
|
||||
struct La_riscv_retval *, \
|
||||
const char *);
|
||||
|
||||
/* Although the RISC-V ABI does not specify that the dynamic section has
|
||||
to be read-only, it needs to be kept for ABI compatibility. */
|
||||
|
||||
#define DL_RO_DYN_SECTION 1
|
||||
|
||||
#include_next <ldsodefs.h>
|
||||
|
||||
#endif
|
||||
|
Loading…
Reference in New Issue
Block a user