/* $OpenBSD: rtld_machine.c,v 1.63 2017/10/10 04:49:10 guenther Exp $ */ /* * Copyright (c) 1999 Dale Rahn * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * */ #define _DYN_LOADER #include #include #include #include #include #include #include "syscall.h" #include "archdep.h" #include "resolve.h" #define DT_PROC(n) ((n) - DT_LOPROC + DT_NUM) void _dl_syncicache(char *from, size_t len); int64_t pcookie __attribute__((section(".openbsd.randomdata"))) __dso_hidden; /* relocation bits */ #define HA(x) (((Elf_Addr)(x) >> 16) + (((Elf_Addr)(x) & 0x00008000) >> 15)) #define L(x) (((Elf_Addr)x) & 0x0000ffff) #define ADDIS_R11_R11 0x3d6b0000 #define ADDIS_R11_R0 0x3d600000 #define ADDI_R11_R11 0x396b0000 #define LWZ_R11_R11 0x816b0000 #define LI_R11 0x39600000 #define ADDIS_R12_R0 0x3d800000 #define ADDI_R12_R12 0x398c0000 #define MCTR_R11 0x7d6903a6 #define MCTR_R12 0x7d8903a6 #define BCTR 0x4e800420 #define BRVAL(from, to) \ ((((Elf32_Addr)(to) - (Elf32_Addr)(&(from))) \ & ~0xfc000000) | 0x48000000) #define BR(from, to) ((from) = BRVAL(from, to)) #define SLWI_R12_R11_1 0x556c083c #define ADD_R11_R12_R11 0x7d6c5a14 /* these are structures/functions offset from PLT region */ #define PLT_CALL_OFFSET 8 #define PLT_INFO_OFFSET 12 #define PLT_1STRELA_OFFSET 18 #define B24_VALID_RANGE(x) \ ((((x) & 0xfe000000) == 0x00000000) || (((x) & 0xfe000000) == 0xfe000000)) void _dl_bind_start(void); /* XXX */ Elf_Addr _dl_bind(elf_object_t *object, int reloff); int _dl_md_reloc(elf_object_t *object, int rel, int relasz) { int i; int numrela; long relrel; int fails = 0; struct load_list *llist; Elf32_Addr loff; Elf32_Rela *relas; /* for jmp table relocations */ Elf32_Addr *pltresolve; Elf32_Addr *pltcall; Elf32_Addr *plttable; Elf32_Addr *pltinfo; Elf32_Addr *first_rela; Elf32_Addr prev_value = 0, prev_ooff = 0; const Elf32_Sym *prev_sym = NULL; loff = object->obj_base; numrela = object->Dyn.info[relasz] / sizeof(Elf32_Rela); relrel = rel == DT_RELA ? object->relacount : 0; relas = (Elf32_Rela *)(object->Dyn.info[rel]); #ifdef DL_PRINTF_DEBUG _dl_printf("object relocation size %x, numrela %x\n", object->Dyn.info[relasz], numrela); #endif if (relas == NULL) return(0); if (relrel > numrela) _dl_die("relcount > numrel: %ld > %d", relrel, numrela); pltresolve = NULL; pltcall = NULL; plttable = NULL; /* for plt relocation usage */ if (object->Dyn.info[DT_JMPREL] != 0 && object->Dyn.info[DT_PROC(DT_PPC_GOT)] == 0) { /* resolver stub not set up */ int nplt; /* Need to construct table to do jumps */ pltresolve = (Elf32_Addr *)(object->Dyn.info[DT_PLTGOT]); pltcall = (Elf32_Addr *)(pltresolve) + PLT_CALL_OFFSET; pltinfo = (Elf32_Addr *)(pltresolve) + PLT_INFO_OFFSET; first_rela = (Elf32_Addr *)(pltresolve) + PLT_1STRELA_OFFSET; nplt = object->Dyn.info[DT_PLTRELSZ]/sizeof(Elf32_Rela); if (nplt >= (2<<12)) { plttable = (Elf32_Addr *) ((Elf32_Addr)first_rela) + (2 * (2<<12)) + (4 * (nplt - (2<<12))); } else { plttable = (Elf32_Addr *) ((Elf32_Addr)first_rela) + (2 * nplt); } pltinfo[0] = (Elf32_Addr)plttable; #ifdef DL_PRINTF_DEBUG _dl_printf("md_reloc: plttbl size %x\n", (object->Dyn.info[DT_PLTRELSZ]/sizeof(Elf32_Rela))); _dl_printf("md_reloc: plttable %x\n", plttable); #endif pltresolve[0] = SLWI_R12_R11_1; pltresolve[1] = ADD_R11_R12_R11; pltresolve[2] = ADDIS_R12_R0 | HA(_dl_bind_start); pltresolve[3] = ADDI_R12_R12 | L(_dl_bind_start); pltresolve[4] = MCTR_R12; pltresolve[5] = ADDIS_R12_R0 | HA(object); pltresolve[6] = ADDI_R12_R12 | L(object); pltresolve[7] = BCTR; _dl_dcbf(&pltresolve[0]); _dl_dcbf(&pltresolve[7]); /* addis r11,r11,.PLTtable@ha*/ pltcall[0] = ADDIS_R11_R11 | HA(plttable); /* lwz r11,plttable@l(r11) */ pltcall[1] = LWZ_R11_R11 | L(plttable); pltcall[2] = MCTR_R11; /* mtctr r11 */ pltcall[3] = BCTR; /* bctr */ _dl_dcbf(&pltcall[0]); _dl_dcbf(&pltcall[3]); } else { first_rela = NULL; } /* * Change protection of all write protected segments in the object * so we can do relocations such as REL24, REL16 etc. After * relocation restore protection. */ if ((object->dyn.textrel == 1) && (rel == DT_REL || rel == DT_RELA)) { for (llist = object->load_list; llist != NULL; llist = llist->next) { if (!(llist->prot & PROT_WRITE)) { _dl_mprotect(llist->start, llist->size, PROT_READ | PROT_WRITE); } } } /* tight loop for leading RELATIVE relocs */ for (i = 0; i < relrel; i++, relas++) { Elf_Addr *r_addr; #ifdef DEBUG const Elf32_Sym *sym; if (ELF32_R_TYPE(relas->r_info) != RELOC_RELATIVE) _dl_die("RELCOUNT wrong"); sym = object->dyn.symtab; sym += ELF32_R_SYM(relas->r_info); if (ELF32_ST_BIND(sym->st_info) != STB_LOCAL || (ELF32_ST_TYPE(sym->st_info) != STT_SECTION && ELF32_ST_TYPE(sym->st_info) != STT_NOTYPE)) _dl_die("RELATIVE relocation against symbol"); #endif r_addr = (Elf_Addr *)(relas->r_offset + loff); *r_addr = loff + relas->r_addend; } for (; i < numrela; i++, relas++) { Elf32_Addr *r_addr = (Elf32_Addr *)(relas->r_offset + loff); Elf32_Addr ooff; const Elf32_Sym *sym, *this; const char *symn; int type; if (ELF32_R_SYM(relas->r_info) == 0xffffff) continue; type = ELF32_R_TYPE(relas->r_info); if (type == RELOC_JMP_SLOT && rel != DT_JMPREL) continue; sym = object->dyn.symtab; sym += ELF32_R_SYM(relas->r_info); symn = object->dyn.strtab + sym->st_name; ooff = 0; this = NULL; if (ELF32_R_SYM(relas->r_info) && !(ELF32_ST_BIND(sym->st_info) == STB_LOCAL && ELF32_ST_TYPE (sym->st_info) == STT_NOTYPE)) { if (sym == prev_sym) { this = sym; /* XXX any non-NULL */ ooff = prev_ooff; } else { ooff = _dl_find_symbol_bysym(object, ELF32_R_SYM(relas->r_info), &this, SYM_SEARCH_ALL|SYM_WARNNOTFOUND| ((type == RELOC_JMP_SLOT) ? SYM_PLT:SYM_NOTPLT), sym, NULL); if (this == NULL) { if (ELF_ST_BIND(sym->st_info) != STB_WEAK) fails++; continue; } prev_sym = sym; prev_value = this->st_value; prev_ooff = ooff; } } /* * For Secure-PLT, RELOC_JMP_SLOT simply sets PLT * slots similarly to how RELOC_GLOB_DAT updates GOT * slots. */ if (type == RELOC_JMP_SLOT && object->Dyn.info[DT_PROC(DT_PPC_GOT)]) type = RELOC_GLOB_DAT; switch (type) { case RELOC_32: if (ELF32_ST_BIND(sym->st_info) == STB_LOCAL && (ELF32_ST_TYPE(sym->st_info) == STT_SECTION || ELF32_ST_TYPE(sym->st_info) == STT_NOTYPE) ) { *r_addr = ooff + relas->r_addend; } else { *r_addr = ooff + prev_value + relas->r_addend; } break; case RELOC_RELATIVE: if (ELF32_ST_BIND(sym->st_info) == STB_LOCAL && (ELF32_ST_TYPE(sym->st_info) == STT_SECTION || ELF32_ST_TYPE(sym->st_info) == STT_NOTYPE) ) { *r_addr = loff + relas->r_addend; #ifdef DL_PRINTF_DEBUG _dl_printf("rel1 r_addr %x val %x loff %x ooff %x addend %x\n", r_addr, loff + relas->r_addend, loff, ooff, relas->r_addend); #endif } else { *r_addr = loff + prev_value + relas->r_addend; } break; case RELOC_JMP_SLOT: { Elf32_Addr target = ooff + prev_value + relas->r_addend; Elf32_Addr val = target - (Elf32_Addr)r_addr; if (!B24_VALID_RANGE(val)){ int index; #ifdef DL_PRINTF_DEBUG _dl_printf(" ooff %x, sym val %x, addend %x" " r_addr %x symn [%s] -> %x\n", ooff, prev_value, relas->r_addend, r_addr, symn, val); #endif /* if offset is > RELOC_24 deal with it */ index = (r_addr - first_rela) >> 1; if (index >= (2 << 12)) { /* addis r11,r11,.PLTtable@ha*/ r_addr[0] = ADDIS_R11_R0 | HA(index*4); r_addr[1] = ADDI_R11_R11 | L(index*4); BR(r_addr[2], pltcall); } else { r_addr[0] = LI_R11 | (index * 4); BR(r_addr[1], pltcall); } _dl_dcbf(&r_addr[0]); _dl_dcbf(&r_addr[2]); val= ooff + prev_value + relas->r_addend; #ifdef DL_PRINTF_DEBUG _dl_printf(" symn [%s] val 0x%x\n", symn, val); #endif plttable[index] = val; } else { /* if the offset is small enough, * branch directly to the dest */ BR(r_addr[0], target); _dl_dcbf(&r_addr[0]); } } break; case RELOC_GLOB_DAT: *r_addr = ooff + prev_value + relas->r_addend; break; #if 1 /* should not be supported ??? */ case RELOC_REL24: { Elf32_Addr val = ooff + prev_value + relas->r_addend - (Elf32_Addr)r_addr; if (!B24_VALID_RANGE(val)) { /* invalid offset */ _dl_die("%s: invalid %s offset %x at %p", object->load_name, "REL24", val, (void *)r_addr); } val &= ~0xfc000003; val |= (*r_addr & 0xfc000003); *r_addr = val; _dl_dcbf(r_addr); } break; #endif #if 1 case RELOC_16_LO: { Elf32_Addr val; val = loff + relas->r_addend; *(Elf32_Half *)r_addr = val; _dl_dcbf(r_addr); } break; #endif #if 1 case RELOC_16_HI: { Elf32_Addr val; val = loff + relas->r_addend; *(Elf32_Half *)r_addr = (val >> 16); _dl_dcbf(r_addr); } break; #endif #if 1 case RELOC_16_HA: { Elf32_Addr val; val = loff + relas->r_addend; *(Elf32_Half *)r_addr = ((val + 0x8000) >> 16); _dl_dcbf(r_addr); } break; #endif case RELOC_REL14_TAKEN: /* val |= 1 << (31-10) XXX? */ case RELOC_REL14: case RELOC_REL14_NTAKEN: { Elf32_Addr val = ooff + prev_value + relas->r_addend - (Elf32_Addr)r_addr; if (((val & 0xffff8000) != 0) && ((val & 0xffff8000) != 0xffff8000)) { /* invalid offset */ _dl_die("%s: invalid %s offset %x at %p", object->load_name, "REL14", val, (void *)r_addr); } val &= ~0xffff0003; val |= (*r_addr & 0xffff0003); *r_addr = val; #ifdef DL_PRINTF_DEBUG _dl_printf("rel 14 %x val %x\n", r_addr, val); #endif _dl_dcbf(r_addr); } break; case RELOC_COPY: { #ifdef DL_PRINTF_DEBUG _dl_printf("copy r_addr %x, sym %x [%s] size %d val %x\n", r_addr, sym, symn, sym->st_size, (ooff + prev_value+ relas->r_addend)); #endif /* * we need to find a symbol, that is not in the current * object, start looking at the beginning of the list, * searching all objects but _not_ the current object, * first one found wins. */ const Elf32_Sym *cpysrc = NULL; Elf32_Addr src_loff; int size; src_loff = 0; src_loff = _dl_find_symbol(symn, &cpysrc, SYM_SEARCH_OTHER|SYM_WARNNOTFOUND| SYM_NOTPLT, sym, object, NULL); if (cpysrc != NULL) { size = sym->st_size; if (sym->st_size != cpysrc->st_size) { _dl_printf("symbols size differ [%s] \n", symn); size = sym->st_size < cpysrc->st_size ? sym->st_size : cpysrc->st_size; } #ifdef DL_PRINTF_DEBUG _dl_printf(" found other symbol at %x size %d\n", src_loff + cpysrc->st_value, cpysrc->st_size); #endif _dl_bcopy((void *)(src_loff + cpysrc->st_value), r_addr, size); } else fails++; } break; case RELOC_NONE: break; default: _dl_die("%s: unsupported relocation '%s' %d at %p\n", object->load_name, symn, ELF32_R_TYPE(relas->r_info), (void *)r_addr ); } } /* reprotect the unprotected segments */ if ((object->dyn.textrel == 1) && (rel == DT_REL || rel == DT_RELA)) { for (llist = object->load_list; llist != NULL; llist = llist->next) { if (!(llist->prot & PROT_WRITE)) _dl_mprotect(llist->start, llist->size, llist->prot); } } return(fails); } void _dl_setup_secure_plt(elf_object_t *object) { Elf32_Addr *got; Elf32_Addr *plt; int numplt, i; /* Relocate processor-specific tags. */ object->Dyn.info[DT_PROC(DT_PPC_GOT)] += object->obj_base; got = (Elf32_Addr *) (Elf32_Rela *)(object->Dyn.info[DT_PROC(DT_PPC_GOT)]); got[1] = (Elf32_Addr)_dl_bind_start; got[2] = (Elf32_Addr)object; plt = (Elf32_Addr *) (Elf32_Rela *)(object->Dyn.info[DT_PLTGOT]); numplt = object->Dyn.info[DT_PLTRELSZ] / sizeof(Elf32_Rela); for (i = 0; i < numplt; i++) plt[i] += object->obj_base; } void _dl_setup_bss_plt(elf_object_t *object) { Elf_Addr *pltresolve; Elf_Addr *first_rela; Elf_RelA *relas; Elf32_Addr *r_addr; int numrela, i; int index; first_rela = (Elf32_Addr *) (((Elf32_Rela *)(object->Dyn.info[DT_JMPREL]))->r_offset + object->obj_base); pltresolve = (Elf32_Addr *)(first_rela) - 18; relas = (Elf32_Rela *)(object->Dyn.info[DT_JMPREL]); numrela = object->Dyn.info[DT_PLTRELSZ] / sizeof(Elf32_Rela); r_addr = (Elf32_Addr *)(relas->r_offset + object->obj_base); for (i = 0, index = 0; i < numrela; i++, r_addr+=2, index++) { if (index >= (2 << 12)) { /* addis r11,r0,.PLTtable@ha*/ r_addr[0] = ADDIS_R11_R0 | HA(index*4); r_addr[1] = ADDI_R11_R11 | L(index*4); BR(r_addr[2], pltresolve); /* only every other slot is used after * index == 2^14 */ r_addr += 2; } else { r_addr[0] = LI_R11 | (index * 4); BR(r_addr[1], pltresolve); } _dl_dcbf(&r_addr[0]); _dl_dcbf(&r_addr[2]); } } /* * Relocate the Global Offset Table (GOT). * This is done by calling _dl_md_reloc on DT_JMPREL for DL_BIND_NOW, * otherwise the lazy binding plt initialization is performed. */ int _dl_md_reloc_got(elf_object_t *object, int lazy) { void *got_addr; int fails = 0; int prot_exec = 0; if (object->Dyn.info[DT_PLTREL] != DT_RELA) return (0); /* * For BSS-PLT, both the GOT and the PLT need to be * executable. Yuck! */ if (object->Dyn.info[DT_PROC(DT_PPC_GOT)] == 0) prot_exec = PROT_EXEC; if (object->traced) lazy = 1; if (!lazy) { fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ); } else { if (object->Dyn.info[DT_PROC(DT_PPC_GOT)]) _dl_setup_secure_plt(object); else _dl_setup_bss_plt(object); } /* mprotect the GOT */ got_addr = _dl_protect_segment(object, 0, "__got_start", "__got_end", PROT_READ|prot_exec); if (prot_exec != 0 && got_addr != NULL) _dl_syncicache(got_addr, 4); return (fails); } Elf_Addr _dl_bind(elf_object_t *object, int reloff) { const Elf_Sym *sym, *this; Elf_Addr *r_addr, ooff; const char *symn; const elf_object_t *sobj; Elf_Addr value; Elf_RelA *relas; Elf32_Addr val; Elf32_Addr *pltresolve; Elf32_Addr *pltcall; Elf32_Addr *pltinfo; Elf32_Addr *plttable; int64_t cookie = pcookie; struct { struct __kbind param[2]; Elf_Addr newval[2]; } buf; struct __kbind *param; size_t psize; relas = (Elf_RelA *)(object->Dyn.info[DT_JMPREL] + reloff); sym = object->dyn.symtab; sym += ELF_R_SYM(relas->r_info); symn = object->dyn.strtab + sym->st_name; this = NULL; ooff = _dl_find_symbol(symn, &this, SYM_SEARCH_ALL|SYM_WARNNOTFOUND|SYM_PLT, sym, object, &sobj); if (this == NULL) _dl_die("lazy binding failed!"); value = ooff + this->st_value; if (__predict_false(sobj->traced) && _dl_trace_plt(sobj, symn)) return (value); r_addr = (Elf_Addr *)(object->obj_base + relas->r_offset); val = value - (Elf32_Addr)r_addr; if (object->Dyn.info[DT_PROC(DT_PPC_GOT)] == 0) { if (!B24_VALID_RANGE(val)) { int index, addr_off; /* if offset is > RELOC_24 deal with it */ index = reloff / sizeof(Elf32_Rela); pltresolve = (Elf32_Addr *) (Elf32_Rela *)(object->Dyn.info[DT_PLTGOT]); pltcall = (Elf32_Addr *)(pltresolve) + PLT_CALL_OFFSET; /* * Early plt entries can make short jumps; later ones * use a 3 word sequence. c.f. _dl_md_reloc_got() */ addr_off = (index >= (2 << 12)) ? 2 : 1; /* * Update plttable before pltcall branch, to make * this a safe race for threads */ pltinfo = (Elf32_Addr *)(pltresolve) + PLT_INFO_OFFSET; plttable = (Elf32_Addr *)pltinfo[0]; buf.param[0].kb_addr = &plttable[index]; buf.param[0].kb_size = sizeof(Elf_Addr); buf.param[1].kb_addr = &r_addr[addr_off]; buf.param[1].kb_size = sizeof(Elf_Addr); buf.newval[0] = value + relas->r_addend; buf.newval[1] = BRVAL(r_addr[addr_off], pltcall); param = &buf.param[0]; psize = sizeof(buf); } else { /* * If the offset is small enough, branch directly to * the dest. We use the _second_ kbind params only. */ buf.param[1].kb_addr = &r_addr[0]; buf.param[1].kb_size = sizeof(Elf_Addr); buf.newval[0] = BRVAL(r_addr[0], value); param = &buf.param[1]; psize = sizeof(struct __kbind) + sizeof(Elf_Addr); } } else { int index = reloff / sizeof(Elf32_Rela); /* * Secure PLT; only needs one update so use the * second kbind params. */ plttable = (Elf32_Addr *) (Elf32_Rela *)(object->Dyn.info[DT_PLTGOT]); buf.param[1].kb_addr = &plttable[index]; buf.param[1].kb_size = sizeof(Elf_Addr); buf.newval[0] = value; param = &buf.param[1]; psize = sizeof(struct __kbind) + sizeof(Elf_Addr); } { register long syscall_num __asm("r0") = SYS_kbind; register void *arg1 __asm("r3") = param; register long arg2 __asm("r4") = psize; register long arg3 __asm("r5") = 0xffffffff & (cookie >> 32); register long arg4 __asm("r6") = 0xffffffff & cookie; __asm volatile("sc" : "+r" (syscall_num), "+r" (arg1), "+r" (arg2) : "r" (arg3), "r" (arg4) : "cc", "memory"); } return (value); } /* should not be defined here, but it is 32 for all powerpc 603-G4 */ #define CACHELINESIZE 32 void _dl_syncicache(char *from, size_t len) { unsigned int off = 0; int l = len + ((int)from & (CACHELINESIZE-1)); while (off < l) { asm volatile ("dcbst %1,%0" :: "r"(from), "r"(off)); asm volatile ("sync"); asm volatile ("icbi %1, %0" :: "r"(from), "r"(off)); asm volatile ("sync"); asm volatile ("isync"); off += CACHELINESIZE; } }