diff options
Diffstat (limited to 'sysdeps/x86/dl-prop.h')
| -rw-r--r-- | sysdeps/x86/dl-prop.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h new file mode 100644 index 0000000000..26c3131ac5 --- /dev/null +++ b/sysdeps/x86/dl-prop.h @@ -0,0 +1,164 @@ +/* Support for GNU properties. x86 version. + Copyright (C) 2018 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 + <http://www.gnu.org/licenses/>. */ + +#ifndef _DL_PROP_H +#define _DL_PROP_H + +#include <not-cancel.h> + +extern void _dl_cet_check (struct link_map *, const char *) + attribute_hidden; +extern void _dl_cet_open_check (struct link_map *) + attribute_hidden; + +static inline void __attribute__ ((always_inline)) +_rtld_main_check (struct link_map *m, const char *program) +{ +#if CET_ENABLED + _dl_cet_check (m, program); +#endif +} + +static inline void __attribute__ ((always_inline)) +_dl_open_check (struct link_map *m) +{ +#if CET_ENABLED + _dl_cet_open_check (m); +#endif +} + +static inline void __attribute__ ((unused)) +_dl_process_cet_property_note (struct link_map *l, + const ElfW(Nhdr) *note, + const ElfW(Addr) size, + const ElfW(Addr) align) +{ +#if CET_ENABLED + /* The NT_GNU_PROPERTY_TYPE_0 note must be aliged to 4 bytes in + 32-bit objects and to 8 bytes in 64-bit objects. Skip notes + with incorrect alignment. */ + if (align != (__ELF_NATIVE_CLASS / 8)) + return; + + const ElfW(Addr) start = (ElfW(Addr)) note; + + while ((ElfW(Addr)) (note + 1) - start < size) + { + /* Find the NT_GNU_PROPERTY_TYPE_0 note. */ + if (note->n_namesz == 4 + && note->n_type == NT_GNU_PROPERTY_TYPE_0 + && memcmp (note + 1, "GNU", 4) == 0) + { + /* Check for invalid property. */ + if (note->n_descsz < 8 + || (note->n_descsz % sizeof (ElfW(Addr))) != 0) + break; + + /* Start and end of property array. */ + unsigned char *ptr = (unsigned char *) (note + 1) + 4; + unsigned char *ptr_end = ptr + note->n_descsz; + + do + { + unsigned int type = *(unsigned int *) ptr; + unsigned int datasz = *(unsigned int *) (ptr + 4); + + ptr += 8; + if ((ptr + datasz) > ptr_end) + break; + + if (type == GNU_PROPERTY_X86_FEATURE_1_AND) + { + /* The size of GNU_PROPERTY_X86_FEATURE_1_AND is 4 + bytes. When seeing GNU_PROPERTY_X86_FEATURE_1_AND, + we stop the search regardless if its size is correct + or not. There is no point to continue if this note + is ill-formed. */ + if (datasz == 4) + { + unsigned int feature_1 = *(unsigned int *) ptr; + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT)) + l->l_cet |= lc_ibt; + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK)) + l->l_cet |= lc_shstk; + } + return; + } + + /* Check the next property item. */ + ptr += ALIGN_UP (datasz, sizeof (ElfW(Addr))); + } + while ((ptr_end - ptr) >= 8); + } + + /* NB: Note sections like .note.ABI-tag and .note.gnu.build-id are + aligned to 4 bytes in 64-bit ELF objects. */ + note = ((const void *) note + + ELF_NOTE_NEXT_OFFSET (note->n_namesz, note->n_descsz, + align)); + } +#endif +} + +#ifdef FILEBUF_SIZE +static inline int __attribute__ ((unused)) +_dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph, + int fd, struct filebuf *fbp) +{ +# if CET_ENABLED + const ElfW(Nhdr) *note; + ElfW(Nhdr) *note_malloced = NULL; + ElfW(Addr) size = ph->p_filesz; + + if (ph->p_offset + size <= (size_t) fbp->len) + note = (const void *) (fbp->buf + ph->p_offset); + else + { + if (size < __MAX_ALLOCA_CUTOFF) + note = alloca (size); + else + { + note_malloced = malloc (size); + note = note_malloced; + } + __lseek (fd, ph->p_offset, SEEK_SET); + if (__read_nocancel (fd, (void *) note, size) != size) + { + if (note_malloced) + free (note_malloced); + return -1; + } + } + + _dl_process_cet_property_note (l, note, size, ph->p_align); + if (note_malloced) + free (note_malloced); +# endif + return 0; +} +#endif + +static inline int __attribute__ ((unused)) +_rtld_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph) +{ + const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr); + _dl_process_cet_property_note (l, note, ph->p_memsz, ph->p_align); + return 0; +} + +#endif /* _DL_PROP_H */ |