/* $OpenBSD: boot.h,v 1.12 2015/08/17 17:13:58 kettenis Exp $ */ /* * Copyright (c) 1998 Per Fogelstrom, Opsycon AB * * 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. * */ /* * IMPORTANT: any functions below are NOT protected by SSP. Please * do not add anything except what is required to reach GOT with * an adjustment. */ #define _DYN_LOADER #include #include #include #include #include #include #include #include "syscall.h" #include "archdep.h" #include "path.h" #include "resolve.h" #include "sod.h" #include "stdlib.h" #include "dl_prebind.h" #ifdef RCRT0 /* * Local decls. */ void _dl_boot_bind(const long, long *, Elf_Dyn *); extern char __plt_start[]; extern char __plt_end[]; extern char __got_start[]; extern char __got_end[]; void _dl_boot_bind(const long sp, long *dl_data, Elf_Dyn *dynamicp) { struct elf_object dynld; /* Resolver data for the loader */ AuxInfo *auxstack; long *stack; Elf_Dyn *dynp; Elf_Addr start; size_t size; int pagesize; int n, argc; char **argv, **envp; long loff; /* * Scan argument and environment vectors. Find dynamic * data vector put after them. */ stack = (long *)sp; argc = *stack++; argv = (char **)stack; envp = &argv[argc + 1]; stack = (long *)envp; while (*stack++ != 0L) ; /* * Zero out dl_data. */ for (n = 0; n <= AUX_entry; n++) dl_data[n] = 0; /* * Dig out auxiliary data set up by exec call. Move all known * tags to an indexed local table for easy access. */ for (auxstack = (AuxInfo *)stack; auxstack->au_id != AUX_null; auxstack++) { if (auxstack->au_id > AUX_entry) continue; dl_data[auxstack->au_id] = auxstack->au_v; } loff = dl_data[AUX_base]; /* XXX assumes ld.so is linked at 0x0 */ /* * We need to do 'selfreloc' in case the code weren't * loaded at the address it was linked to. * * Scan the DYNAMIC section for the loader. * Cache the data for easier access. */ #if defined(__alpha__) dynp = (Elf_Dyn *)((long)_DYNAMIC); #elif defined(__sparc__) || defined(__sparc64__) || defined(__powerpc__) || \ defined(__hppa__) || defined(__sh__) dynp = dynamicp; #else dynp = (Elf_Dyn *)((long)_DYNAMIC + loff); #endif _dl_memset(dynld.Dyn.info, 0, sizeof(dynld.Dyn.info)); while (dynp != NULL && dynp->d_tag != DT_NULL) { if (dynp->d_tag < DT_NUM) dynld.Dyn.info[dynp->d_tag] = dynp->d_un.d_val; else if (dynp->d_tag >= DT_LOPROC && dynp->d_tag < DT_LOPROC + DT_PROCNUM) dynld.Dyn.info[dynp->d_tag - DT_LOPROC + DT_NUM] = dynp->d_un.d_val; if (dynp->d_tag == DT_TEXTREL) dynld.dyn.textrel = 1; dynp++; } /* * Do the 'bootstrap relocation'. This is really only needed if * the code was loaded at another location than it was linked to. * We don't do undefined symbols resolving (to difficult..) */ /* "relocate" dyn.X values if they represent addresses */ { int i, val; /* must be code, not pic data */ int table[20]; i = 0; table[i++] = DT_PLTGOT; table[i++] = DT_HASH; table[i++] = DT_STRTAB; table[i++] = DT_SYMTAB; table[i++] = DT_RELA; table[i++] = DT_INIT; table[i++] = DT_FINI; table[i++] = DT_REL; table[i++] = DT_JMPREL; table[i++] = DT_PLTREL; /* other processors insert their extras here */ table[i++] = DT_NULL; for (i = 0; table[i] != DT_NULL; i++) { val = table[i]; if (val >= DT_LOPROC && val < DT_LOPROC + DT_PROCNUM) val = val - DT_LOPROC + DT_NUM; else if (val >= DT_NUM || val == DT_PLTREL) continue; if (dynld.Dyn.info[val] != 0) dynld.Dyn.info[val] += loff; } } for (n = 0; n < 2; n++) { u_int32_t rs; Elf_Rel *rp; int i; switch (n) { case 0: if (dynld.Dyn.info[DT_PLTREL] != DT_REL) continue; rp = (Elf_Rel *)(dynld.Dyn.info[DT_JMPREL]); rs = dynld.dyn.pltrelsz; break; case 1: rp = (Elf_Rel *)(dynld.Dyn.info[DT_REL]); rs = dynld.dyn.relsz; break; default: rp = NULL; rs = 0; } for (i = 0; i < rs; i += sizeof (Elf_Rel), rp++) { Elf_Addr *ra; const Elf_Sym *sp; sp = dynld.dyn.symtab; sp += ELF_R_SYM(rp->r_info); if (ELF_R_SYM(rp->r_info) && sp->st_value == 0) { #if 0 /* cannot printf in this function */ _dl_wrstderr("Dynamic loader failure: self bootstrapping impossible.\n"); _dl_wrstderr("Undefined symbol: "); _dl_wrstderr((char *)dynld.dyn.strtab + sp->st_name); #endif #ifdef RCRT0 continue; #else _dl_exit(5); #endif } ra = (Elf_Addr *)(rp->r_offset + loff); RELOC_REL(rp, sp, ra, loff); } } for (n = 0; n < 2; n++) { unsigned long rs; Elf_RelA *rp; int i; switch (n) { case 0: if (dynld.Dyn.info[DT_PLTREL] != DT_RELA) continue; rp = (Elf_RelA *)(dynld.Dyn.info[DT_JMPREL]); rs = dynld.dyn.pltrelsz; break; case 1: rp = (Elf_RelA *)(dynld.Dyn.info[DT_RELA]); rs = dynld.dyn.relasz; break; default: rp = NULL; rs = 0; } for (i = 0; i < rs; i += sizeof (Elf_RelA), rp++) { Elf_Addr *ra; const Elf_Sym *sp; sp = dynld.dyn.symtab; sp += ELF_R_SYM(rp->r_info); if (ELF_R_SYM(rp->r_info) && sp->st_value == 0) { #if 0 _dl_wrstderr("Dynamic loader failure: self bootstrapping impossible.\n"); _dl_wrstderr("Undefined symbol: "); _dl_wrstderr((char *)dynld.dyn.strtab + sp->st_name); #endif #ifdef RCRT0 continue; #else _dl_exit(6); #endif } ra = (Elf_Addr *)(rp->r_offset + loff); RELOC_RELA(rp, sp, ra, loff, dynld.dyn.pltgot); } } RELOC_GOT(&dynld, loff); /* * we have been fully relocated here, so most things no longer * need the loff adjustment */ /* * No further changes to the PLT and/or GOT are needed so make * them read-only. */ if (dl_data[AUX_pagesz] != 0) pagesize = dl_data[AUX_pagesz]; else pagesize = 4096; #if defined(__alpha__) || defined(__powerpc__) || defined(__sparc__) || \ defined(__sparc64__) start = ELF_TRUNC((Elf_Addr)__plt_start, pagesize); size = ELF_ROUND((Elf_Addr)__plt_end - start, pagesize); mprotect((void *)start, size, PROT_READ); #endif start = ELF_TRUNC((Elf_Addr)__got_start, pagesize); size = ELF_ROUND((Elf_Addr)__got_end - start, pagesize); mprotect((void *)start, size, GOT_PERMS); } #ifdef __alpha__ void _reloc_alpha_got(Elf_Dyn *dynp, Elf_Addr relocbase); void _reloc_alpha_got(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 *)((caddr_t)rela + relasz); for (; rela < relalim; rela++) { if (ELF64_R_TYPE(rela->r_info) != RELOC_RELATIVE) continue; where = (Elf_Addr *)(relocbase + rela->r_offset); *where += (Elf_Addr)relocbase; } } #endif #endif /* RCRT0 */