size_t gelf_fsize(Elf *e, Elf_Type t, size_t c, unsigned int v) { if (e == NULL) { LIBELF_SET_ERROR(ARGUMENT, 0); return (0); } if (e->e_class == ELFCLASS32 || e->e_class == ELFCLASS64) return (_libelf_fsize(t, e->e_class, v, c)); LIBELF_SET_ERROR(ARGUMENT, 0); return (0); }
/* * Retrieve counts for sections, phdrs and the section string table index * from section header #0 of the ELF object. */ static int _libelf_load_extended(Elf *e, int ec, uint64_t shoff, uint16_t phnum, uint16_t strndx) { Elf_Scn *scn; size_t fsz; int (*xlator)(unsigned char *_d, size_t _dsz, unsigned char *_s, size_t _c, int _swap); uint32_t shtype; assert(STAILQ_EMPTY(&e->e_u.e_elf.e_scn)); fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, 1); assert(fsz > 0); if (e->e_rawsize < shoff + fsz) { /* raw file too small */ LIBELF_SET_ERROR(HEADER, 0); return (0); } if ((scn = _libelf_allocate_scn(e, (size_t) 0)) == NULL) return (0); xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); (*xlator)((unsigned char *) &scn->s_shdr, sizeof(scn->s_shdr), (unsigned char *) e->e_rawfile + shoff, (size_t) 1, e->e_byteorder != LIBELF_PRIVATE(byteorder)); #define GET_SHDR_MEMBER(M) ((ec == ELFCLASS32) ? scn->s_shdr.s_shdr32.M : \ scn->s_shdr.s_shdr64.M) if ((shtype = GET_SHDR_MEMBER(sh_type)) != SHT_NULL) { LIBELF_SET_ERROR(SECTION, 0); return (0); } e->e_u.e_elf.e_nscn = (size_t) GET_SHDR_MEMBER(sh_size); e->e_u.e_elf.e_nphdr = (phnum != PN_XNUM) ? phnum : GET_SHDR_MEMBER(sh_info); e->e_u.e_elf.e_strndx = (strndx != SHN_XINDEX) ? strndx : GET_SHDR_MEMBER(sh_link); #undef GET_SHDR_MEMBER return (1); }
void * _libelf_ehdr(Elf *e, int ec, int allocate) { void *ehdr; size_t fsz, msz; uint16_t phnum, shnum, strndx; uint64_t shoff; int (*xlator)(unsigned char *_d, size_t _dsz, unsigned char *_s, size_t _c, int _swap); assert(ec == ELFCLASS32 || ec == ELFCLASS64); if (e == NULL || e->e_kind != ELF_K_ELF) { LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); } if (e->e_class != ELFCLASSNONE && e->e_class != ec) { LIBELF_SET_ERROR(CLASS, 0); return (NULL); } if (e->e_version != EV_CURRENT) { LIBELF_SET_ERROR(VERSION, 0); return (NULL); } if (e->e_class == ELFCLASSNONE) e->e_class = ec; if (ec == ELFCLASS32) ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr32; else ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr64; if (ehdr != NULL) /* already have a translated ehdr */ return (ehdr); fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1); assert(fsz > 0); if (e->e_cmd != ELF_C_WRITE && e->e_rawsize < fsz) { LIBELF_SET_ERROR(HEADER, 0); return (NULL); } msz = _libelf_msize(ELF_T_EHDR, ec, EV_CURRENT); assert(msz > 0); if ((ehdr = calloc((size_t) 1, msz)) == NULL) { LIBELF_SET_ERROR(RESOURCE, 0); return (NULL); } if (ec == ELFCLASS32) { e->e_u.e_elf.e_ehdr.e_ehdr32 = ehdr; EHDR_INIT(ehdr,32); } else { e->e_u.e_elf.e_ehdr.e_ehdr64 = ehdr; EHDR_INIT(ehdr,64); } if (allocate) e->e_flags |= ELF_F_DIRTY; if (e->e_cmd == ELF_C_WRITE) return (ehdr); xlator = _libelf_get_translator(ELF_T_EHDR, ELF_TOMEMORY, ec); (*xlator)((unsigned char*) ehdr, msz, e->e_rawfile, (size_t) 1, e->e_byteorder != LIBELF_PRIVATE(byteorder)); if (ec == ELFCLASS32) { phnum = ((Elf32_Ehdr *) ehdr)->e_phnum; shnum = ((Elf32_Ehdr *) ehdr)->e_shnum; shoff = ((Elf32_Ehdr *) ehdr)->e_shoff; strndx = ((Elf32_Ehdr *) ehdr)->e_shstrndx; } else { phnum = ((Elf64_Ehdr *) ehdr)->e_phnum; shnum = ((Elf64_Ehdr *) ehdr)->e_shnum; shoff = ((Elf64_Ehdr *) ehdr)->e_shoff; strndx = ((Elf64_Ehdr *) ehdr)->e_shstrndx; } if (shnum >= SHN_LORESERVE || (shoff == 0LL && (shnum != 0 || phnum == PN_XNUM || strndx == SHN_XINDEX))) { LIBELF_SET_ERROR(HEADER, 0); return (NULL); } /* * If extended numbering is being used, read the correct * number of sections and program header entries. */ if ((shnum == 0 && shoff != 0) || phnum == PN_XNUM || strndx == SHN_XINDEX) { if (_libelf_load_extended(e, ec, shoff, phnum, strndx) == 0) return (NULL); } else { /* not using extended numbering */ e->e_u.e_elf.e_nphdr = phnum; e->e_u.e_elf.e_nscn = shnum; e->e_u.e_elf.e_strndx = strndx; } return (ehdr); }
size_t elf64_fsize(Elf_Type t, size_t c, unsigned int v) { return (_libelf_fsize(t, ELFCLASS64, v, c)); }
/* * Load an ELF section table and create a list of Elf_Scn structures. */ static int _libelf_load_scn(Elf *e, void *ehdr) { int ec, swapbytes; size_t fsz, i, shnum; uint64_t shoff; char *src; Elf32_Ehdr *eh32; Elf64_Ehdr *eh64; Elf_Scn *scn; void (*xlator)(char *_d, char *_s, size_t _c, int _swap); assert(e != NULL); assert(ehdr != NULL); assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0); #define CHECK_EHDR(E,EH) do { \ if (fsz != (EH)->e_shentsize || \ shoff + fsz * shnum > e->e_rawsize) { \ LIBELF_SET_ERROR(HEADER, 0); \ return (0); \ } \ } while (0) ec = e->e_class; fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); assert(fsz > 0); shnum = e->e_u.e_elf.e_nscn; if (ec == ELFCLASS32) { eh32 = (Elf32_Ehdr *) ehdr; shoff = (uint64_t) eh32->e_shoff; CHECK_EHDR(e, eh32); } else { eh64 = (Elf64_Ehdr *) ehdr; shoff = eh64->e_shoff; CHECK_EHDR(e, eh64); } xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder); src = e->e_rawfile + shoff; /* * If the file is using extended numbering then section #0 * would have already been read in. */ i = 0; if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) == STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next)); i = 1; src += fsz; } for (; i < shnum; i++, src += fsz) { if ((scn = _libelf_allocate_scn(e, i)) == NULL) return (0); (*xlator)((char *) &scn->s_shdr, src, (size_t) 1, swapbytes); if (ec == ELFCLASS32) { scn->s_offset = scn->s_rawoff = scn->s_shdr.s_shdr32.sh_offset; scn->s_size = scn->s_shdr.s_shdr32.sh_size; } else { scn->s_offset = scn->s_rawoff = scn->s_shdr.s_shdr64.sh_offset; scn->s_size = scn->s_shdr.s_shdr64.sh_size; } } e->e_flags |= LIBELF_F_SHDRS_LOADED; return (1); }