#define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "pthread_impl.h" #include "libc.h" #include "dynlink.h" #include "malloc_impl.h" static void error(const char *, ...); #define MAXP2(a,b) (-(-(a)&-(b))) #define ALIGN(x,y) ((x)+(y)-1 & -(y)) struct debug { int ver; void *head; void (*bp)(void); int state; void *base; }; struct td_index { size_t args[2]; struct td_index *next; }; struct dso { #if DL_FDPIC struct fdpic_loadmap *loadmap; #else unsigned char *base; #endif char *name; size_t *dynv; struct dso *next, *prev; Phdr *phdr; int phnum; size_t phentsize; Sym *syms; Elf_Symndx *hashtab; uint32_t *ghashtab; int16_t *versym; char *strings; struct dso *syms_next, *lazy_next; size_t *lazy, lazy_cnt; unsigned char *map; size_t map_len; dev_t dev; ino_t ino; char relocated; char constructed; char kernel_mapped; struct dso **deps, *needed_by; char *rpath_orig, *rpath; struct tls_module tls; size_t tls_id; size_t relro_start, relro_end; void **new_dtv; unsigned char *new_tls; volatile int new_dtv_idx, new_tls_idx; struct td_index *td_index; struct dso *fini_next; char *shortname; #if DL_FDPIC unsigned char *base; #else struct fdpic_loadmap *loadmap; #endif struct funcdesc { void *addr; size_t *got; } *funcdescs; size_t *got; char buf[]; }; struct symdef { Sym *sym; struct dso *dso; }; void __init_libc(char **, char *); static struct builtin_tls { char c; struct pthread pt; void *space[16]; } builtin_tls[1]; #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt) #define ADDEND_LIMIT 4096 static size_t *saved_addends, *apply_addends_to; static struct dso ldso; static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head; static char *env_path, *sys_path; static unsigned long long gencnt; static int runtime; static int ldd_mode; static int ldso_fail; static int noload; static jmp_buf *rtld_fail; static pthread_rwlock_t lock; static struct debug debug; static struct tls_module *tls_tail; static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN; static size_t static_tls_cnt; static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE }; static struct fdpic_loadmap *app_loadmap; static struct fdpic_dummy_loadmap app_dummy_loadmap; static struct dso *const nodeps_dummy; struct debug *_dl_debug_addr = &debug; extern hidden int __malloc_replaced; hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0; extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void); weak_alias(__init_array_start, __init_array_end); weak_alias(__fini_array_start, __fini_array_end); static int dl_strcmp(const char *l, const char *r) { for (; *l==*r && *l; l++, r++); return *(unsigned char *)l - *(unsigned char *)r; } #define strcmp(l,r) dl_strcmp(l,r) /* Compute load address for a virtual address in a given dso. */ #if DL_FDPIC static void *laddr(const struct dso *p, size_t v) { size_t j=0; if (!p->loadmap) return p->base + v; for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++); return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr); } static void *laddr_pg(const struct dso *p, size_t v) { size_t j=0; size_t pgsz = PAGE_SIZE; if (!p->loadmap) return p->base + v; for (j=0; ; j++) { size_t a = p->loadmap->segs[j].p_vaddr; size_t b = a + p->loadmap->segs[j].p_memsz; a &= -pgsz; b += pgsz-1; b &= -pgsz; if (v-aloadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr); } #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \ laddr(p, v), (p)->got }) #else #define laddr(p, v) (void *)((p)->base + (v)) #define laddr_pg(p, v) laddr(p, v) #define fpaddr(p, v) ((void (*)())laddr(p, v)) #endif static void decode_vec(size_t *v, size_t *a, size_t cnt) { size_t i; for (i=0; i>24 & 0xf0; } return h & 0xfffffff; } static uint32_t gnu_hash(const char *s0) { const unsigned char *s = (void *)s0; uint_fast32_t h = 5381; for (; *s; s++) h += h*32 + *s; return h; } static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso) { size_t i; Sym *syms = dso->syms; Elf_Symndx *hashtab = dso->hashtab; char *strings = dso->strings; for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) { if ((!dso->versym || dso->versym[i] >= 0) && (!strcmp(s, strings+syms[i].st_name))) return syms+i; } return 0; } static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s) { uint32_t nbuckets = hashtab[0]; uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4); uint32_t i = buckets[h1 % nbuckets]; if (!i) return 0; uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]); for (h1 |= 1; ; i++) { uint32_t h2 = *hashval++; if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0) && !strcmp(s, dso->strings + dso->syms[i].st_name)) return dso->syms+i; if (h2 & 1) break; } return 0; } static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask) { const size_t *bloomwords = (const void *)(hashtab+4); size_t f = bloomwords[fofs & (hashtab[2]-1)]; if (!(f & fmask)) return 0; f >>= (h1 >> hashtab[3]) % (8 * sizeof f); if (!(f & 1)) return 0; return gnu_lookup(h1, hashtab, dso, s); } #define OK_TYPES (1<syms_next) { Sym *sym; if ((ght = dso->ghashtab)) { sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm); } else { if (!h) h = sysv_hash(s); sym = sysv_lookup(s, h, dso); } if (!sym) continue; if (!sym->st_shndx) if (need_def || (sym->st_info&0xf) == STT_TLS || ARCH_SYM_REJECT_UND(sym)) continue; if (!sym->st_value) if ((sym->st_info&0xf) != STT_TLS) continue; if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue; if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue; def.sym = sym; def.dso = dso; break; } return def; } hidden ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic(); static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride) { unsigned char *base = dso->base; Sym *syms = dso->syms; char *strings = dso->strings; Sym *sym; const char *name; void *ctx; int type; int sym_index; struct symdef def; size_t *reloc_addr; size_t sym_val; size_t tls_val; size_t addend; int skip_relative = 0, reuse_addends = 0, save_slot = 0; if (dso == &ldso) { /* Only ldso's REL table needs addend saving/reuse. */ if (rel == apply_addends_to) reuse_addends = 1; skip_relative = 1; } for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) { if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue; type = R_TYPE(rel[1]); if (type == REL_NONE) continue; reloc_addr = laddr(dso, rel[0]); if (stride > 2) { addend = rel[2]; } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) { addend = 0; } else if (reuse_addends) { /* Save original addend in stage 2 where the dso * chain consists of just ldso; otherwise read back * saved addend since the inline one was clobbered. */ if (head==&ldso) saved_addends[save_slot] = *reloc_addr; addend = saved_addends[save_slot++]; } else { addend = *reloc_addr; } sym_index = R_SYM(rel[1]); if (sym_index) { sym = syms + sym_index; name = strings + sym->st_name; ctx = type==REL_COPY ? head->syms_next : head; def = (sym->st_info&0xf) == STT_SECTION ? (struct symdef){ .dso = dso, .sym = sym } : find_sym(ctx, name, type==REL_PLT); if (!def.sym && (sym->st_shndx != SHN_UNDEF || sym->st_info>>4 != STB_WEAK)) { if (dso->lazy && (type==REL_PLT || type==REL_GOT)) { dso->lazy[3*dso->lazy_cnt+0] = rel[0]; dso->lazy[3*dso->lazy_cnt+1] = rel[1]; dso->lazy[3*dso->lazy_cnt+2] = addend; dso->lazy_cnt++; continue; } error("Error relocating %s: %s: symbol not found", dso->name, name); if (runtime) longjmp(*rtld_fail, 1); continue; } } else { sym = 0; def.sym = 0; def.dso = dso; } sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0; tls_val = def.sym ? def.sym->st_value : 0; if ((type == REL_TPOFF || type == REL_TPOFF_NEG) && runtime && def.dso->tls_id > static_tls_cnt) { error("Error relocating %s: %s: initial-exec TLS " "resolves to dynamic definition in %s", dso->name, name, def.dso->name); longjmp(*rtld_fail, 1); } switch(type) { case REL_NONE: break; case REL_OFFSET: addend -= (size_t)reloc_addr; case REL_SYMBOLIC: case REL_GOT: case REL_PLT: *reloc_addr = sym_val + addend; break; case REL_RELATIVE: *reloc_addr = (size_t)base + addend; break; case REL_SYM_OR_REL: if (sym) *reloc_addr = sym_val + addend; else *reloc_addr = (size_t)base + addend; break; case REL_COPY: memcpy(reloc_addr, (void *)sym_val, sym->st_size); break; case REL_OFFSET32: *(uint32_t *)reloc_addr = sym_val + addend - (size_t)reloc_addr; break; case REL_FUNCDESC: *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs + (def.sym - def.dso->syms)) : 0; break; case REL_FUNCDESC_VAL: if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val; else *reloc_addr = sym_val; reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0; break; case REL_DTPMOD: *reloc_addr = def.dso->tls_id; break; case REL_DTPOFF: *reloc_addr = tls_val + addend - DTP_OFFSET; break; #ifdef TLS_ABOVE_TP case REL_TPOFF: *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend; break; #else case REL_TPOFF: *reloc_addr = tls_val - def.dso->tls.offset + addend; break; case REL_TPOFF_NEG: *reloc_addr = def.dso->tls.offset - tls_val + addend; break; #endif case REL_TLSDESC: if (stride<3) addend = reloc_addr[1]; if (runtime && def.dso->tls_id > static_tls_cnt) { struct td_index *new = malloc(sizeof *new); if (!new) { error( "Error relocating %s: cannot allocate TLSDESC for %s", dso->name, sym ? name : "(local)" ); longjmp(*rtld_fail, 1); } new->next = dso->td_index; dso->td_index = new; new->args[0] = def.dso->tls_id; new->args[1] = tls_val + addend; reloc_addr[0] = (size_t)__tlsdesc_dynamic; reloc_addr[1] = (size_t)new; } else { reloc_addr[0] = (size_t)__tlsdesc_static; #ifdef TLS_ABOVE_TP reloc_addr[1] = tls_val + def.dso->tls.offset + TPOFF_K + addend; #else reloc_addr[1] = tls_val - def.dso->tls.offset + addend; #endif } break; default: error("Error relocating %s: unsupported relocation type %d", dso->name, type); if (runtime) longjmp(*rtld_fail, 1); continue; } } } static void redo_lazy_relocs() { struct dso *p = lazy_head, *next; lazy_head = 0; for (; p; p=next) { next = p->lazy_next; size_t size = p->lazy_cnt*3*sizeof(size_t); p->lazy_cnt = 0; do_relocs(p, p->lazy, size, 3); if (p->lazy_cnt) { p->lazy_next = lazy_head; lazy_head = p; } else { free(p->lazy); p->lazy = 0; p->lazy_next = 0; } } } /* A huge hack: to make up for the wastefulness of shared libraries * needing at least a page of dirty memory even if they have no global * data, we reclaim the gaps at the beginning and end of writable maps * and "donate" them to the heap. */ static void reclaim(struct dso *dso, size_t start, size_t end) { if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end; if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start; if (start >= end) return; char *base = laddr_pg(dso, start); __malloc_donate(base, base+(end-start)); } static void reclaim_gaps(struct dso *dso) { Phdr *ph = dso->phdr; size_t phcnt = dso->phnum; for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) { if (ph->p_type!=PT_LOAD) continue; if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue; reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr); reclaim(dso, ph->p_vaddr+ph->p_memsz, ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE); } } static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off) { static int no_map_fixed; char *q; if (!no_map_fixed) { q = mmap(p, n, prot, flags|MAP_FIXED, fd, off); if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL) return q; no_map_fixed = 1; } /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */ if (flags & MAP_ANONYMOUS) { memset(p, 0, n); return p; } ssize_t r; if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED; for (q=p; n; q+=r, off+=r, n-=r) { r = read(fd, q, n); if (r < 0 && errno != EINTR) return MAP_FAILED; if (!r) { memset(q, 0, n); break; } } return p; } static void unmap_library(struct dso *dso) { if (dso->loadmap) { size_t i; for (i=0; iloadmap->nsegs; i++) { if (!dso->loadmap->segs[i].p_memsz) continue; munmap((void *)dso->loadmap->segs[i].addr, dso->loadmap->segs[i].p_memsz); } free(dso->loadmap); } else if (dso->map && dso->map_len) { munmap(dso->map, dso->map_len); } } static void *map_library(int fd, struct dso *dso) { Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)]; void *allocated_buf=0; size_t phsize; size_t addr_min=SIZE_MAX, addr_max=0, map_len; size_t this_min, this_max; size_t nsegs = 0; off_t off_start; Ehdr *eh; Phdr *ph, *ph0; unsigned prot; unsigned char *map=MAP_FAILED, *base; size_t dyn=0; size_t tls_image=0; size_t i; ssize_t l = read(fd, buf, sizeof buf); eh = buf; if (l<0) return 0; if (le_type != ET_DYN && eh->e_type != ET_EXEC)) goto noexec; phsize = eh->e_phentsize * eh->e_phnum; if (phsize > sizeof buf - sizeof *eh) { allocated_buf = malloc(phsize); if (!allocated_buf) return 0; l = pread(fd, allocated_buf, phsize, eh->e_phoff); if (l < 0) goto error; if (l != phsize) goto noexec; ph = ph0 = allocated_buf; } else if (eh->e_phoff + phsize > l) { l = pread(fd, buf+1, phsize, eh->e_phoff); if (l < 0) goto error; if (l != phsize) goto noexec; ph = ph0 = (void *)(buf + 1); } else { ph = ph0 = (void *)((char *)buf + eh->e_phoff); } for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) { if (ph->p_type == PT_DYNAMIC) { dyn = ph->p_vaddr; } else if (ph->p_type == PT_TLS) { tls_image = ph->p_vaddr; dso->tls.align = ph->p_align; dso->tls.len = ph->p_filesz; dso->tls.size = ph->p_memsz; } else if (ph->p_type == PT_GNU_RELRO) { dso->relro_start = ph->p_vaddr & -PAGE_SIZE; dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE; } if (ph->p_type != PT_LOAD) continue; nsegs++; if (ph->p_vaddr < addr_min) { addr_min = ph->p_vaddr; off_start = ph->p_offset; prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) | ((ph->p_flags&PF_W) ? PROT_WRITE: 0) | ((ph->p_flags&PF_X) ? PROT_EXEC : 0)); } if (ph->p_vaddr+ph->p_memsz > addr_max) { addr_max = ph->p_vaddr+ph->p_memsz; } } if (!dyn) goto noexec; if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) { dso->loadmap = calloc(1, sizeof *dso->loadmap + nsegs * sizeof *dso->loadmap->segs); if (!dso->loadmap) goto error; dso->loadmap->nsegs = nsegs; for (ph=ph0, i=0; ie_phentsize)) { if (ph->p_type != PT_LOAD) continue; prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) | ((ph->p_flags&PF_W) ? PROT_WRITE: 0) | ((ph->p_flags&PF_X) ? PROT_EXEC : 0)); map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1), prot, MAP_PRIVATE, fd, ph->p_offset & -PAGE_SIZE); if (map == MAP_FAILED) { unmap_library(dso); goto error; } dso->loadmap->segs[i].addr = (size_t)map + (ph->p_vaddr & PAGE_SIZE-1); dso->loadmap->segs[i].p_vaddr = ph->p_vaddr; dso->loadmap->segs[i].p_memsz = ph->p_memsz; i++; if (prot & PROT_WRITE) { size_t brk = (ph->p_vaddr & PAGE_SIZE-1) + ph->p_filesz; size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE; size_t pgend = brk + ph->p_memsz - ph->p_filesz + PAGE_SIZE-1 & -PAGE_SIZE; if (pgend > pgbrk && mmap_fixed(map+pgbrk, pgend-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, off_start) == MAP_FAILED) goto error; memset(map + brk, 0, pgbrk-brk); } } map = (void *)dso->loadmap->segs[0].addr; map_len = 0; goto done_mapping; } addr_max += PAGE_SIZE-1; addr_max &= -PAGE_SIZE; addr_min &= -PAGE_SIZE; off_start &= -PAGE_SIZE; map_len = addr_max - addr_min + off_start; /* The first time, we map too much, possibly even more than * the length of the file. This is okay because we will not * use the invalid part; we just need to reserve the right * amount of virtual address space to map over later. */ map = DL_NOMMU_SUPPORT ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) : mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start); if (map==MAP_FAILED) goto error; dso->map = map; dso->map_len = map_len; /* If the loaded file is not relocatable and the requested address is * not available, then the load operation must fail. */ if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) { errno = EBUSY; goto error; } base = map - addr_min; dso->phdr = 0; dso->phnum = 0; for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) { if (ph->p_type != PT_LOAD) continue; /* Check if the programs headers are in this load segment, and * if so, record the address for use by dl_iterate_phdr. */ if (!dso->phdr && eh->e_phoff >= ph->p_offset && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) { dso->phdr = (void *)(base + ph->p_vaddr + (eh->e_phoff-ph->p_offset)); dso->phnum = eh->e_phnum; dso->phentsize = eh->e_phentsize; } this_min = ph->p_vaddr & -PAGE_SIZE; this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE; off_start = ph->p_offset & -PAGE_SIZE; prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) | ((ph->p_flags&PF_W) ? PROT_WRITE: 0) | ((ph->p_flags&PF_X) ? PROT_EXEC : 0)); /* Reuse the existing mapping for the lowest-address LOAD */ if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT) if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED) goto error; if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) { size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz; size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE; memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1); if (pgbrk-(size_t)base < this_max && mmap_fixed((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) goto error; } } for (i=0; ((size_t *)(base+dyn))[i]; i+=2) if (((size_t *)(base+dyn))[i]==DT_TEXTREL) { if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) && errno != ENOSYS) goto error; break; } done_mapping: dso->base = base; dso->dynv = laddr(dso, dyn); if (dso->tls.size) dso->tls.image = laddr(dso, tls_image); free(allocated_buf); return map; noexec: errno = ENOEXEC; error: if (map!=MAP_FAILED) unmap_library(dso); free(allocated_buf); return 0; } static int path_open(const char *name, const char *s, char *buf, size_t buf_size) { size_t l; int fd; for (;;) { s += strspn(s, ":\n"); l = strcspn(s, ":\n"); if (l-1 >= INT_MAX) return -1; if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) { if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd; switch (errno) { case ENOENT: case ENOTDIR: case EACCES: case ENAMETOOLONG: break; default: /* Any negative value but -1 will inhibit * futher path search. */ return -2; } } s += l; } } static int fixup_rpath(struct dso *p, char *buf, size_t buf_size) { size_t n, l; const char *s, *t, *origin; char *d; if (p->rpath || !p->rpath_orig) return 0; if (!strchr(p->rpath_orig, '$')) { p->rpath = p->rpath_orig; return 0; } n = 0; s = p->rpath_orig; while ((t=strchr(s, '$'))) { if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9)) return 0; s = t+1; n++; } if (n > SSIZE_MAX/PATH_MAX) return 0; if (p->kernel_mapped) { /* $ORIGIN searches cannot be performed for the main program * when it is suid/sgid/AT_SECURE. This is because the * pathname is under the control of the caller of execve. * For libraries, however, $ORIGIN can be processed safely * since the library's pathname came from a trusted source * (either system paths or a call to dlopen). */ if (libc.secure) return 0; l = readlink("/proc/self/exe", buf, buf_size); if (l == -1) switch (errno) { case ENOENT: case ENOTDIR: case EACCES: break; default: return -1; } if (l >= buf_size) return 0; buf[l] = 0; origin = buf; } else { origin = p->name; } t = strrchr(origin, '/'); if (t) { l = t-origin; } else { /* Normally p->name will always be an absolute or relative * pathname containing at least one '/' character, but in the * case where ldso was invoked as a command to execute a * program in the working directory, app.name may not. Fix. */ origin = "."; l = 1; } /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */ if (libc.secure && *origin != '/') return 0; p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1); if (!p->rpath) return -1; d = p->rpath; s = p->rpath_orig; while ((t=strchr(s, '$'))) { memcpy(d, s, t-s); d += t-s; memcpy(d, origin, l); d += l; /* It was determined previously that the '$' is followed * either by "ORIGIN" or "{ORIGIN}". */ s = t + 7 + 2*(t[1]=='{'); } strcpy(d, s); return 0; } static void decode_dyn(struct dso *p) { size_t dyn[DYN_CNT]; decode_vec(p->dynv, dyn, DYN_CNT); p->syms = laddr(p, dyn[DT_SYMTAB]); p->strings = laddr(p, dyn[DT_STRTAB]); if (dyn[0]&(1<hashtab = laddr(p, dyn[DT_HASH]); if (dyn[0]&(1<rpath_orig = p->strings + dyn[DT_RPATH]; if (dyn[0]&(1<rpath_orig = p->strings + dyn[DT_RUNPATH]; if (dyn[0]&(1<got = laddr(p, dyn[DT_PLTGOT]); if (search_vec(p->dynv, dyn, DT_GNU_HASH)) p->ghashtab = laddr(p, *dyn); if (search_vec(p->dynv, dyn, DT_VERSYM)) p->versym = laddr(p, *dyn); } static size_t count_syms(struct dso *p) { if (p->hashtab) return p->hashtab[1]; size_t nsym, i; uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4); uint32_t *hashval; for (i = nsym = 0; i < p->ghashtab[0]; i++) { if (buckets[i] > nsym) nsym = buckets[i]; } if (nsym) { hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]); do nsym++; while (!(*hashval++ & 1)); } return nsym; } static void *dl_mmap(size_t n) { void *p; int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE; #ifdef SYS_mmap2 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0); #else p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0); #endif return p == MAP_FAILED ? 0 : p; } static void makefuncdescs(struct dso *p) { static int self_done; size_t nsym = count_syms(p); size_t i, size = nsym * sizeof(*p->funcdescs); if (!self_done) { p->funcdescs = dl_mmap(size); self_done = 1; } else { p->funcdescs = malloc(size); } if (!p->funcdescs) { if (!runtime) a_crash(); error("Error allocating function descriptors for %s", p->name); longjmp(*rtld_fail, 1); } for (i=0; isyms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) { p->funcdescs[i].addr = laddr(p, p->syms[i].st_value); p->funcdescs[i].got = p->got; } else { p->funcdescs[i].addr = 0; p->funcdescs[i].got = 0; } } } static struct dso *load_library(const char *name, struct dso *needed_by) { char buf[2*NAME_MAX+2]; const char *pathname; unsigned char *map; struct dso *p, temp_dso = {0}; int fd; struct stat st; size_t alloc_size; int n_th = 0; int is_self = 0; if (!*name) { errno = EINVAL; return 0; } /* Catch and block attempts to reload the implementation itself */ if (name[0]=='l' && name[1]=='i' && name[2]=='b') { static const char reserved[] = "c.pthread.rt.m.dl.util.xnet."; const char *rp, *next; for (rp=reserved; *rp; rp=next) { next = strchr(rp, '.') + 1; if (strncmp(name+3, rp, next-rp) == 0) break; } if (*rp) { if (ldd_mode) { /* Track which names have been resolved * and only report each one once. */ static unsigned reported; unsigned mask = 1U<<(rp-reserved); if (!(reported & mask)) { reported |= mask; dprintf(1, "\t%s => %s (%p)\n", name, ldso.name, ldso.base); } } is_self = 1; } } if (!strcmp(name, ldso.name)) is_self = 1; if (is_self) { if (!ldso.prev) { tail->next = &ldso; ldso.prev = tail; tail = &ldso; } return &ldso; } if (strchr(name, '/')) { pathname = name; fd = open(name, O_RDONLY|O_CLOEXEC); } else { /* Search for the name to see if it's already loaded */ for (p=head->next; p; p=p->next) { if (p->shortname && !strcmp(p->shortname, name)) { return p; } } if (strlen(name) > NAME_MAX) return 0; fd = -1; if (env_path) fd = path_open(name, env_path, buf, sizeof buf); for (p=needed_by; fd == -1 && p; p=p->needed_by) { if (fixup_rpath(p, buf, sizeof buf) < 0) fd = -2; /* Inhibit further search. */ if (p->rpath) fd = path_open(name, p->rpath, buf, sizeof buf); } if (fd == -1) { if (!sys_path) { char *prefix = 0; size_t prefix_len; if (ldso.name[0]=='/') { char *s, *t, *z; for (s=t=z=ldso.name; *s; s++) if (*s=='/') z=t, t=s; prefix_len = z-ldso.name; if (prefix_len < PATH_MAX) prefix = ldso.name; } if (!prefix) { prefix = ""; prefix_len = 0; } char etc_ldso_path[prefix_len + 1 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"]; snprintf(etc_ldso_path, sizeof etc_ldso_path, "%.*s/etc/ld-musl-" LDSO_ARCH ".path", (int)prefix_len, prefix); FILE *f = fopen(etc_ldso_path, "rbe"); if (f) { if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) { free(sys_path); sys_path = ""; } fclose(f); } else if (errno != ENOENT) { sys_path = ""; } } if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib"; fd = path_open(name, sys_path, buf, sizeof buf); } pathname = buf; } if (fd < 0) return 0; if (fstat(fd, &st) < 0) { close(fd); return 0; } for (p=head->next; p; p=p->next) { if (p->dev == st.st_dev && p->ino == st.st_ino) { /* If this library was previously loaded with a * pathname but a search found the same inode, * setup its shortname so it can be found by name. */ if (!p->shortname && pathname != name) p->shortname = strrchr(p->name, '/')+1; close(fd); return p; } } map = noload ? 0 : map_library(fd, &temp_dso); close(fd); if (!map) return 0; /* Avoid the danger of getting two versions of libc mapped into the * same process when an absolute pathname was used. The symbols * checked are chosen to catch both musl and glibc, and to avoid * false positives from interposition-hack libraries. */ decode_dyn(&temp_dso); if (find_sym(&temp_dso, "__libc_start_main", 1).sym && find_sym(&temp_dso, "stdin", 1).sym) { unmap_library(&temp_dso); return load_library("libc.so", needed_by); } /* Past this point, if we haven't reached runtime yet, ldso has * committed either to use the mapped library or to abort execution. * Unmapping is not possible, so we can safely reclaim gaps. */ if (!runtime) reclaim_gaps(&temp_dso); /* Allocate storage for the new DSO. When there is TLS, this * storage must include a reservation for all pre-existing * threads to obtain copies of both the new TLS, and an * extended DTV capable of storing an additional slot for * the newly-loaded DSO. */ alloc_size = sizeof *p + strlen(pathname) + 1; if (runtime && temp_dso.tls.image) { size_t per_th = temp_dso.tls.size + temp_dso.tls.align + sizeof(void *) * (tls_cnt+3); n_th = libc.threads_minus_1 + 1; if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX; else alloc_size += n_th * per_th; } p = calloc(1, alloc_size); if (!p) { unmap_library(&temp_dso); return 0; } memcpy(p, &temp_dso, sizeof temp_dso); p->dev = st.st_dev; p->ino = st.st_ino; p->needed_by = needed_by; p->name = p->buf; strcpy(p->name, pathname); /* Add a shortname only if name arg was not an explicit pathname. */ if (pathname != name) p->shortname = strrchr(p->name, '/')+1; if (p->tls.image) { p->tls_id = ++tls_cnt; tls_align = MAXP2(tls_align, p->tls.align); #ifdef TLS_ABOVE_TP p->tls.offset = tls_offset + ( (tls_align-1) & -(tls_offset + (uintptr_t)p->tls.image) ); tls_offset += p->tls.size; #else tls_offset += p->tls.size + p->tls.align - 1; tls_offset -= (tls_offset + (uintptr_t)p->tls.image) & (p->tls.align-1); p->tls.offset = tls_offset; #endif p->new_dtv = (void *)(-sizeof(size_t) & (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t))); p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1)); if (tls_tail) tls_tail->next = &p->tls; else libc.tls_head = &p->tls; tls_tail = &p->tls; } tail->next = p; p->prev = tail; tail = p; if (DL_FDPIC) makefuncdescs(p); if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base); return p; } static void load_deps(struct dso *p) { size_t i, ndeps=0; struct dso ***deps = &p->deps, **tmp, *dep; for (; p; p=p->next) { for (i=0; p->dynv[i]; i+=2) { if (p->dynv[i] != DT_NEEDED) continue; dep = load_library(p->strings + p->dynv[i+1], p); if (!dep) { error("Error loading shared library %s: %m (needed by %s)", p->strings + p->dynv[i+1], p->name); if (runtime) longjmp(*rtld_fail, 1); continue; } if (runtime) { tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2)); if (!tmp) longjmp(*rtld_fail, 1); tmp[ndeps++] = dep; tmp[ndeps] = 0; *deps = tmp; } } } if (!*deps) *deps = (struct dso **)&nodeps_dummy; } static void load_preload(char *s) { int tmp; char *z; for (z=s; *z; s=z) { for ( ; *s && (isspace(*s) || *s==':'); s++); for (z=s; *z && !isspace(*z) && *z!=':'; z++); tmp = *z; *z = 0; load_library(s, 0); *z = tmp; } } static void add_syms(struct dso *p) { if (!p->syms_next && syms_tail != p) { syms_tail->syms_next = p; syms_tail = p; } } static void revert_syms(struct dso *old_tail) { struct dso *p, *next; /* Chop off the tail of the list of dsos that participate in * the global symbol table, reverting them to RTLD_LOCAL. */ for (p=old_tail; p; p=next) { next = p->syms_next; p->syms_next = 0; } syms_tail = old_tail; } static void do_mips_relocs(struct dso *p, size_t *got) { size_t i, j, rel[2]; unsigned char *base = p->base; i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO); if (p==&ldso) { got += i; } else { while (i--) *got++ += (size_t)base; } j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM); i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO); Sym *sym = p->syms + j; rel[0] = (unsigned char *)got - base; for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) { rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT); do_relocs(p, rel, sizeof rel, 2); } } static void reloc_all(struct dso *p) { size_t dyn[DYN_CNT]; for (; p; p=p->next) { if (p->relocated) continue; decode_vec(p->dynv, dyn, DYN_CNT); if (NEED_MIPS_GOT_RELOCS) do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT])); do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ], 2+(dyn[DT_PLTREL]==DT_RELA)); do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2); do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3); if (head != &ldso && p->relro_start != p->relro_end && mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ) && errno != ENOSYS) { error("Error relocating %s: RELRO protection failed: %m", p->name); if (runtime) longjmp(*rtld_fail, 1); } p->relocated = 1; } } static void kernel_mapped_dso(struct dso *p) { size_t min_addr = -1, max_addr = 0, cnt; Phdr *ph = p->phdr; for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) { if (ph->p_type == PT_DYNAMIC) { p->dynv = laddr(p, ph->p_vaddr); } else if (ph->p_type == PT_GNU_RELRO) { p->relro_start = ph->p_vaddr & -PAGE_SIZE; p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE; } if (ph->p_type != PT_LOAD) continue; if (ph->p_vaddr < min_addr) min_addr = ph->p_vaddr; if (ph->p_vaddr+ph->p_memsz > max_addr) max_addr = ph->p_vaddr+ph->p_memsz; } min_addr &= -PAGE_SIZE; max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE; p->map = p->base + min_addr; p->map_len = max_addr - min_addr; p->kernel_mapped = 1; } void __libc_exit_fini() { struct dso *p; size_t dyn[DYN_CNT]; for (p=fini_head; p; p=p->fini_next) { if (!p->constructed) continue; decode_vec(p->dynv, dyn, DYN_CNT); if (dyn[0] & (1<prev) { if (p->constructed) continue; p->constructed = 1; decode_vec(p->dynv, dyn, DYN_CNT); if (dyn[0] & ((1<fini_next = fini_head; fini_head = p; } #ifndef NO_LEGACY_INITFINI if ((dyn[0] & (1<