/* $NetBSD: mdreloc.c,v 1.55.12.1 2023/08/01 16:34:59 martin Exp $ */ /*- * Copyright (c) 1999, 2002 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Paul Kranenburg and by Charles M. Hannum. * * 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``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 FOUNDATION OR CONTRIBUTORS * 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. */ #include #ifndef lint __RCSID("$NetBSD: mdreloc.c,v 1.55.12.1 2023/08/01 16:34:59 martin Exp $"); #endif /* not lint */ #include #include #include #include #include #include #include "rtldenv.h" #include "debug.h" #include "rtld.h" /* * The following table holds for each relocation type: * - the width in bits of the memory location the relocation * applies to (not currently used) * - the number of bits the relocation value must be shifted to the * right (i.e. discard least significant bits) to fit into * the appropriate field in the instruction word. * - flags indicating whether * * the relocation involves a symbol * * the relocation is relative to the current position * * the relocation is for a GOT entry * * the relocation is relative to the load address * */ #define _RF_S 0x80000000 /* Resolve symbol */ #define _RF_A 0x40000000 /* Use addend */ #define _RF_P 0x20000000 /* Location relative */ #define _RF_G 0x10000000 /* GOT offset */ #define _RF_B 0x08000000 /* Load address relative */ #define _RF_U 0x04000000 /* Unaligned */ #define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */ #define _RF_RS(s) ( (s) & 0xff) /* right shift */ static const int reloc_target_flags[R_TYPE(TLS_TPOFF64)+1] = { 0, /* NONE */ _RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */ _RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */ _RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */ _RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */ _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */ _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */ _RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */ _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */ _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */ _RF_SZ(32) | _RF_RS(0), /* COPY */ _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_DAT */ _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */ _RF_A| _RF_B| _RF_SZ(32) | _RF_RS(0), /* RELATIVE */ _RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */ /* TLS and 64 bit relocs not listed here... */ }; #ifdef RTLD_DEBUG_RELOC static const char *reloc_names[] = { "NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8", "DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22", "22", "13", "LO10", "GOT10", "GOT13", "GOT22", "PC10", "PC22", "WPLT30", "COPY", "GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32", /* not used with 32bit userland, besides a few of the TLS ones */ "PLT32", "HIPLT22", "LOPLT10", "LOPLT10", "PCPLT22", "PCPLT32", "10", "11", "64", "OLO10", "HH22", "HM10", "LM22", "PC_HH22", "PC_HM10", "PC_LM22", "WDISP16", "WDISP19", "GLOB_JMP", "7", "5", "6", "DISP64", "PLT64", "HIX22", "LOX10", "H44", "M44", "L44", "REGISTER", "UA64", "UA16", "TLS_GD_HI22", "TLS_GD_LO10", "TLS_GD_ADD", "TLS_GD_CALL", "TLS_LDM_HI22", "TLS_LDM_LO10", "TLS_LDM_ADD", "TLS_LDM_CALL", "TLS_LDO_HIX22", "TLS_LDO_LOX10", "TLS_LDO_ADD", "TLS_IE_HI22", "TLS_IE_LO10", "TLS_IE_LD", "TLS_IE_LDX", "TLS_IE_ADD", "TLS_LE_HIX22", "TLS_LE_LOX10", "TLS_DTPMOD32", "TLS_DTPMOD64", "TLS_DTPOFF32", "TLS_DTPOFF64", "TLS_TPOFF32", "TLS_TPOFF64", }; #endif #define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0) #define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0) #define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0) #define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0) #define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0) #define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff) #define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff) #define RELOC_TLS(t) (t >= R_TYPE(TLS_GD_HI22)) static const int reloc_target_bitmask[] = { #define _BM(x) (~(-(1ULL << (x)))) 0, /* NONE */ _BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */ _BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */ _BM(30), _BM(22), /* WDISP30, WDISP22 */ _BM(22), _BM(22), /* HI22, _22 */ _BM(13), _BM(10), /* RELOC_13, _LO10 */ _BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */ _BM(10), _BM(22), /* _PC10, _PC22 */ _BM(30), 0, /* _WPLT30, _COPY */ -1, -1, -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */ _BM(32) /* _UA32 */ #undef _BM }; #define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t]) void _rtld_bind_start(void); void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); static inline int _rtld_relocate_plt_object(const Obj_Entry *, const Elf_Rela *, Elf_Addr *); void _rtld_setup_pltgot(const Obj_Entry *obj) { /* * PLTGOT is the PLT on the sparc. * The first entry holds the call the dynamic linker. * We construct a `call' sequence that transfers * to `_rtld_bind_start()'. * The second entry holds the object identification. * Note: each PLT entry is three words long. */ #define SAVE 0x9de3bfa0 /* i.e. `save %sp,-96,%sp' */ #define CALL 0x40000000 #define NOP 0x01000000 obj->pltgot[0] = SAVE; obj->pltgot[1] = CALL | ((Elf_Addr) &_rtld_bind_start - (Elf_Addr) &obj->pltgot[1]) >> 2; obj->pltgot[2] = NOP; obj->pltgot[3] = (Elf_Addr) obj; } void _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) { const Elf_Rela *rela = 0, *relalim; Elf_Addr relasz = 0; Elf_Addr *where; for (; dynp->d_tag != DT_NULL; dynp++) { switch (dynp->d_tag) { case DT_RELA: rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); break; case DT_RELASZ: relasz = dynp->d_un.d_val; break; } } relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); for (; rela < relalim; rela++) { where = (Elf_Addr *)(relocbase + rela->r_offset); *where += (Elf_Addr)(relocbase + rela->r_addend); } } int _rtld_relocate_nonplt_objects(Obj_Entry *obj) { const Elf_Rela *rela; const Elf_Sym *def = NULL; const Obj_Entry *defobj = NULL; unsigned long last_symnum = ULONG_MAX; for (rela = obj->rela; rela < obj->relalim; rela++) { Elf_Addr *where; Elf_Word type, value, mask; unsigned long symnum; where = (Elf_Addr *) (obj->relocbase + rela->r_offset); type = ELF_R_TYPE(rela->r_info); if (type == R_TYPE(NONE)) continue; /* We do JMP_SLOTs in _rtld_bind() below */ if (type == R_TYPE(JMP_SLOT)) continue; /* IFUNC relocations are handled in _rtld_call_ifunc */ if (type == R_TYPE(IRELATIVE)) { if (obj->ifunc_remaining_nonplt == 0) { obj->ifunc_remaining_nonplt = obj->relalim - rela; } continue; } /* COPY relocs are also handled elsewhere */ if (type == R_TYPE(COPY)) continue; /* * We use the fact that relocation types are an `enum' * Note: R_SPARC_TLS_TPOFF64 is currently numerically largest. */ if (type > R_TYPE(TLS_TPOFF64)) return (-1); value = rela->r_addend; if (RELOC_RESOLVE_SYMBOL(type) || RELOC_TLS(type)) { symnum = ELF_R_SYM(rela->r_info); if (last_symnum != symnum) { last_symnum = symnum; def = _rtld_find_symdef(symnum, obj, &defobj, false); if (def == NULL) return -1; } } /* * Handle TLS relocations here, they are different. */ if (RELOC_TLS(type)) { switch (type) { case R_TYPE(TLS_DTPMOD32): *where = (Elf_Addr)defobj->tlsindex; rdbg(("TLS_DTPMOD32 %s in %s --> %p", obj->strtab + obj->symtab[symnum].st_name, obj->path, (void *)*where)); break; case R_TYPE(TLS_DTPOFF32): *where = (Elf_Addr)(def->st_value + rela->r_addend); rdbg(("TLS_DTPOFF32 %s in %s --> %p", obj->strtab + obj->symtab[symnum].st_name, obj->path, (void *)*where)); break; case R_TYPE(TLS_TPOFF32): if (!defobj->tls_static && _rtld_tls_offset_allocate(__UNCONST(defobj))) return -1; *where = (Elf_Addr)(def->st_value - defobj->tlsoffset + rela->r_addend); rdbg(("TLS_TPOFF32 %s in %s --> %p", obj->strtab + obj->symtab[symnum].st_name, obj->path, (void *)*where)); break; } continue; } /* * If it is no TLS relocation (handled above), we can not * deal with it if it is beyound R_SPARC_6. */ if (type > R_TYPE(6)) return (-1); /* * Handle relative relocs here, as an optimization. */ if (type == R_TYPE(RELATIVE)) { *where += (Elf_Addr)(obj->relocbase + value); rdbg(("RELATIVE in %s --> %p", obj->path, (void *)*where)); continue; } if (RELOC_RESOLVE_SYMBOL(type)) { /* Add in the symbol's absolute address */ value += (Elf_Word)(defobj->relocbase + def->st_value); } if (RELOC_PC_RELATIVE(type)) { value -= (Elf_Word)where; } if (RELOC_BASE_RELATIVE(type)) { /* * Note that even though sparcs use `Elf_rela' * exclusively we still need the implicit memory addend * in relocations referring to GOT entries. * Undoubtedly, someone f*cked this up in the distant * past, and now we're stuck with it in the name of * compatibility for all eternity.. * * In any case, the implicit and explicit should be * mutually exclusive. We provide a check for that * here. */ #define DIAGNOSTIC #ifdef DIAGNOSTIC if (value != 0 && *where != 0) { xprintf("BASE_REL(%s): where=%p, *where 0x%x, " "addend=0x%x, base %p\n", obj->path, where, *where, rela->r_addend, obj->relocbase); } #endif value += (Elf_Word)(obj->relocbase + *where); } mask = RELOC_VALUE_BITMASK(type); value >>= RELOC_VALUE_RIGHTSHIFT(type); value &= mask; if (RELOC_UNALIGNED(type)) { /* Handle unaligned relocations. */ Elf_Addr tmp = 0; char *ptr = (char *)where; int i, size = RELOC_TARGET_SIZE(type)/8; /* Read it in one byte at a time. */ for (i=0; i> (8*i)) & 0xff); #ifdef RTLD_DEBUG_RELOC value = (Elf_Word)tmp; #endif } else { *where &= ~mask; *where |= value; #ifdef RTLD_DEBUG_RELOC value = (Elf_Word)*where; #endif } #ifdef RTLD_DEBUG_RELOC if (RELOC_RESOLVE_SYMBOL(type)) { rdbg(("%s %s in %s --> %p in %s", reloc_names[type], obj->strtab + obj->symtab[symnum].st_name, obj->path, (void *)value, defobj->path)); } else { rdbg(("%s in %s --> %p", reloc_names[type], obj->path, (void *)value)); } #endif } return (0); } int _rtld_relocate_plt_lazy(Obj_Entry *obj) { const Elf_Rela *rela; for (rela = obj->pltrelalim; rela-- > obj->pltrela; ) { if (ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_IREL)) obj->ifunc_remaining = obj->pltrelalim - rela + 1; } return 0; } caddr_t _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) { const Elf_Rela *rela = (const Elf_Rela *)((const uint8_t *)obj->pltrela + reloff); Elf_Addr value; int err; value = 0; /* XXX gcc */ _rtld_shared_enter(); err = _rtld_relocate_plt_object(obj, rela, &value); if (err) _rtld_die(); _rtld_shared_exit(); return (caddr_t)value; } int _rtld_relocate_plt_objects(const Obj_Entry *obj) { const Elf_Rela *rela = obj->pltrela; for (; rela < obj->pltrelalim; rela++) if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) return -1; return 0; } static inline int _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp) { const Elf_Sym *def; const Obj_Entry *defobj; Elf_Word *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); Elf_Addr value; unsigned long info = rela->r_info; if (ELF_R_TYPE(info) == R_TYPE(JMP_IREL)) return 0; assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); if (__predict_false(def == NULL)) return -1; if (__predict_false(def == &_rtld_sym_zero)) return 0; if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { if (tp == NULL) return 0; value = _rtld_resolve_ifunc(defobj, def); } else { value = (Elf_Addr)(defobj->relocbase + def->st_value); } rdbg(("bind now/fixup in %s --> new=%p", defobj->strtab + def->st_name, (void *)value)); sparc_write_branch(where + 1, (void *)value); if (tp) *tp = value; return 0; }