diff options
| -rw-r--r-- | elf/dl-lookup.c | 5 | ||||
| -rw-r--r-- | sysdeps/generic/dl-protected.h | 54 |
2 files changed, 59 insertions, 0 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index eea217e..430359a 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -24,6 +24,7 @@ #include <ldsodefs.h> #include <dl-hash.h> #include <dl-machine.h> +#include <dl-protected.h> #include <sysdep-cancel.h> #include <libc-lock.h> #include <tls.h> @@ -527,6 +528,10 @@ do_lookup_x (const char *undef_name, uint_fast32_t new_hash, if (__glibc_unlikely (dl_symbol_visibility_binds_local_p (sym))) goto skip; + if (ELFW(ST_VISIBILITY) (sym->st_other) == STV_PROTECTED) + _dl_check_protected_symbol (undef_name, undef_map, ref, map, + type_class); + switch (ELFW(ST_BIND) (sym->st_info)) { case STB_WEAK: diff --git a/sysdeps/generic/dl-protected.h b/sysdeps/generic/dl-protected.h new file mode 100644 index 0000000..244d020 --- /dev/null +++ b/sysdeps/generic/dl-protected.h @@ -0,0 +1,54 @@ +/* Support for STV_PROTECTED visibility. Generic 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_PROTECTED_H +#define _DL_PROTECTED_H + +static inline void __attribute__ ((always_inline)) +_dl_check_protected_symbol (const char *undef_name, + const struct link_map *undef_map, + const ElfW(Sym) *ref, + const struct link_map *map, + int type_class) +{ + if (undef_map != NULL + && undef_map->l_type == lt_executable + && !(undef_map->l_1_needed + & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS) + && (map->l_1_needed + & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)) + { + if ((type_class & ELF_RTYPE_CLASS_COPY)) + /* Disallow copy relocations in executable against protected + data symbols in a shared object which needs indirect external + access. */ + _dl_signal_error (0, map->l_name, undef_name, + N_("copy relocation against non-copyable protected symbol")); + else if (ref->st_value != 0 + && ref->st_shndx == SHN_UNDEF + && (type_class & ELF_RTYPE_CLASS_PLT)) + /* Disallow non-zero symbol values of undefined symbols in + executable, which are used as the function pointer, against + protected function symbols in a shared object with indirect + external access. */ + _dl_signal_error (0, map->l_name, undef_name, + N_("non-canonical reference to canonical protected function")); + } +} + +#endif /* _DL_PROTECTED_H */ |