diff options
| -rw-r--r-- | sysdeps/aarch64/dl-bti.c | 67 | ||||
| -rw-r--r-- | sysdeps/aarch64/dl-prop.h | 8 | ||||
| -rw-r--r-- | sysdeps/aarch64/linkmap.h | 2 |
3 files changed, 52 insertions, 25 deletions
diff --git a/sysdeps/aarch64/dl-bti.c b/sysdeps/aarch64/dl-bti.c index 8f4728adce..34b5294f92 100644 --- a/sysdeps/aarch64/dl-bti.c +++ b/sysdeps/aarch64/dl-bti.c @@ -19,39 +19,62 @@ #include <errno.h> #include <libintl.h> #include <ldsodefs.h> +#include <sys/mman.h> -static int -enable_bti (struct link_map *map, const char *program) +/* See elf/dl-load.h. */ +#ifndef MAP_COPY +# define MAP_COPY (MAP_PRIVATE | MAP_DENYWRITE) +#endif + +/* Enable BTI protection for MAP. */ + +void +_dl_bti_protect (struct link_map *map, int fd) { + const size_t pagesz = GLRO(dl_pagesize); const ElfW(Phdr) *phdr; - unsigned prot; for (phdr = map->l_phdr; phdr < &map->l_phdr[map->l_phnum]; ++phdr) if (phdr->p_type == PT_LOAD && (phdr->p_flags & PF_X)) { - void *start = (void *) (phdr->p_vaddr + map->l_addr); - size_t len = phdr->p_memsz; + size_t vstart = ALIGN_DOWN (phdr->p_vaddr, pagesz); + size_t vend = ALIGN_UP (phdr->p_vaddr + phdr->p_filesz, pagesz); + off_t off = ALIGN_DOWN (phdr->p_offset, pagesz); + void *start = (void *) (vstart + map->l_addr); + size_t len = vend - vstart; - prot = PROT_EXEC | PROT_BTI; + /* Add PROT_BTI. */ + unsigned prot = PROT_EXEC | PROT_BTI; if (phdr->p_flags & PF_R) prot |= PROT_READ; if (phdr->p_flags & PF_W) prot |= PROT_WRITE; - if (__mprotect (start, len, prot) < 0) - { - if (program) - _dl_fatal_printf ("%s: mprotect failed to turn on BTI\n", - map->l_name); - else - _dl_signal_error (errno, map->l_name, "dlopen", - N_("mprotect failed to turn on BTI")); - } + if (fd == -1) + /* Ignore failures for kernel mapped binaries. */ + __mprotect (start, len, prot); + else + map->l_mach.bti_fail = __mmap (start, len, prot, + MAP_FIXED|MAP_COPY|MAP_FILE, + fd, off) == MAP_FAILED; } - return 0; } -/* Enable BTI for MAP and its dependencies. */ + +static void +bti_failed (struct link_map *l, const char *program) +{ + if (program) + _dl_fatal_printf ("%s: %s: failed to turn on BTI protection\n", + program, l->l_name); + else + /* Note: the errno value is not available any more. */ + _dl_signal_error (0, l->l_name, "dlopen", + N_("failed to turn on BTI protection")); +} + + +/* Report BTI protection failures for MAP and its dependencies. */ void _dl_bti_check (struct link_map *map, const char *program) @@ -59,16 +82,14 @@ _dl_bti_check (struct link_map *map, const char *program) if (!GLRO(dl_aarch64_cpu_features).bti) return; - if (map->l_mach.bti) - enable_bti (map, program); + if (map->l_mach.bti_fail) + bti_failed (map, program); unsigned int i = map->l_searchlist.r_nlist; while (i-- > 0) { struct link_map *l = map->l_initfini[i]; - if (l->l_init_called) - continue; - if (l->l_mach.bti) - enable_bti (l, program); + if (l->l_mach.bti_fail) + bti_failed (l, program); } } diff --git a/sysdeps/aarch64/dl-prop.h b/sysdeps/aarch64/dl-prop.h index 2016d1472e..e926e54984 100644 --- a/sysdeps/aarch64/dl-prop.h +++ b/sysdeps/aarch64/dl-prop.h @@ -19,6 +19,8 @@ #ifndef _DL_PROP_H #define _DL_PROP_H +extern void _dl_bti_protect (struct link_map *, int) attribute_hidden; + extern void _dl_bti_check (struct link_map *, const char *) attribute_hidden; @@ -43,6 +45,10 @@ static inline int _dl_process_gnu_property (struct link_map *l, int fd, uint32_t type, uint32_t datasz, void *data) { + if (!GLRO(dl_aarch64_cpu_features).bti) + /* Skip note processing. */ + return 0; + if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND) { /* Stop if the property note is ill-formed. */ @@ -51,7 +57,7 @@ _dl_process_gnu_property (struct link_map *l, int fd, uint32_t type, unsigned int feature_1 = *(unsigned int *) data; if (feature_1 & GNU_PROPERTY_AARCH64_FEATURE_1_BTI) - l->l_mach.bti = true; + _dl_bti_protect (l, fd); /* Stop if we processed the property note. */ return 0; diff --git a/sysdeps/aarch64/linkmap.h b/sysdeps/aarch64/linkmap.h index 847a03ace2..b3f7663b07 100644 --- a/sysdeps/aarch64/linkmap.h +++ b/sysdeps/aarch64/linkmap.h @@ -22,5 +22,5 @@ struct link_map_machine { ElfW(Addr) plt; /* Address of .plt */ void *tlsdesc_table; /* Address of TLS descriptor hash table. */ - bool bti; /* Branch Target Identification is enabled. */ + bool bti_fail; /* Failed to enable Branch Target Identification. */ }; |