From f6a54a304223666ea4af73260c99c830d7726eca Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Fri, 15 Oct 2021 14:35:31 -0300 Subject: [PATCH] elf: Fix elf_get_dynamic_info() for bootstrap THe d6d89608ac8c 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. (cherry picked from commit 5118dcac68c4eadfd6304bb33adde63d062dc07f) Resolved conflicts: elf/rtld.c - Manual merge. --- elf/dl-load.c | 2 +- elf/dl-reloc-static-pie.c | 3 +- elf/get-dynamic-info.h | 95 +++++++++++++++++++++++---------------- elf/rtld.c | 4 +- elf/setup-vdso.h | 2 +- 5 files changed, 61 insertions(+), 45 deletions(-) diff --git a/elf/dl-load.c b/elf/dl-load.c index fb3da5aa56..a920b12a90 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -1296,7 +1296,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, if (l->l_ld != 0) 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. */ diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c index ababafcf98..757205affe 100644 --- a/elf/dl-reloc-static-pie.c +++ b/elf/dl-reloc-static-pie.c @@ -25,7 +25,6 @@ #include -#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); diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h index 1ac0663d1f..f63e07dc6d 100644 --- a/elf/get-dynamic-info.h +++ b/elf/get-dynamic-info.h @@ -26,7 +26,8 @@ #include 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 diff --git a/elf/rtld.c b/elf/rtld.c index 0a4c3d4fed..e52e9cd66e 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -548,7 +548,7 @@ _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 (); bootstrap_map.l_ld_readonly = DL_RO_DYN_SECTION; - 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; @@ -1616,7 +1616,7 @@ 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 diff --git a/elf/setup-vdso.h b/elf/setup-vdso.h index f44748bc98..3f20578046 100644 --- a/elf/setup-vdso.h +++ b/elf/setup-vdso.h @@ -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;