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Fixes for elf64-pie main identification

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This commit is contained in:
pancake 2015-11-10 13:00:19 +01:00
parent b701626cfc
commit 495d209a61
2 changed files with 46 additions and 10 deletions
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54
libr/bin/format/elf/elf.c
View File

@ -628,6 +628,20 @@ ut64 Elf_(r_bin_elf_get_entry_offset)(struct Elf_(r_bin_elf_obj_t) *bin) {
return Elf_(r_bin_elf_v2p) (bin, bin->ehdr.e_entry);
}
static ut64 getmainsymbol(struct Elf_(r_bin_elf_obj_t) *bin) {
struct r_bin_elf_symbol_t *symbol;
int i;
if (!(symbol = Elf_(r_bin_elf_get_symbols) (bin, R_BIN_ELF_SYMBOLS)))
return UT64_MAX;
for (i = 0; !symbol[i].last; i++) {
if (!strcmp (symbol[i].name, "main")) {
ut64 paddr = symbol[i].offset;
return Elf_(r_bin_elf_p2v) (bin, paddr);
}
}
return UT64_MAX;
}
ut64 Elf_(r_bin_elf_get_main_offset)(struct Elf_(r_bin_elf_obj_t) *bin) {
ut64 entry = Elf_(r_bin_elf_get_entry_offset) (bin);
ut8 buf[512];
@ -641,6 +655,7 @@ ut64 Elf_(r_bin_elf_get_main_offset)(struct Elf_(r_bin_elf_obj_t) *bin) {
eprintf ("Warning: read (main)\n");
return 0;
}
// find 'main' symbol first
// TODO: Use arch to identify arch before memcmp's
// ARM
ut64 text = Elf_(r_bin_elf_get_section_offset)(bin, ".text");
@ -720,10 +735,19 @@ ut64 Elf_(r_bin_elf_get_main_offset)(struct Elf_(r_bin_elf_obj_t) *bin) {
return Elf_(r_bin_elf_v2p) (bin, addr);
}
// X86-PIE
if (buf[0x00] == 0x48 && buf[0x1e] == 0x8d && buf[0x11] == 0xe8) {
ut32 *main = (ut32*)(buf + 0x30);
ut64 vmain = Elf_(r_bin_elf_p2v) (bin, (ut64)*main);
ut64 ventry = Elf_(r_bin_elf_p2v) (bin, entry);
if (vmain>>16 == ventry>>16) {
return (ut64)vmain;
}
}
// X86-PIE
if (buf[0x1d] == 0x48 && buf[0x1e] == 0x8b) {
if (!memcmp (buf, "\x31\xed\x49\x89", 4)) {// linux
ut64 maddr, baddr;
ut32 n32, *num = (ut32 *)(buf+0x20);
ut32 n32, *num = (ut32 *)(buf + 0x20);
maddr = entry + 0x24 + *num;
if (r_buf_read_at (bin->b, maddr, (ut8*)&n32, sizeof (n32)) == -1) {
eprintf ("Warning: read (maddr) 2\n");
@ -757,13 +781,24 @@ ut64 Elf_(r_bin_elf_get_main_offset)(struct Elf_(r_bin_elf_obj_t) *bin) {
return Elf_(r_bin_elf_v2p) (bin, addr);
}
#endif
/* linux64 pie main */
/* linux64 pie main -- probably buggy in some cases */
if (buf[29] == 0x48 && buf[30] == 0x8d) { // lea rdi, qword [rip-0x21c4]
ut8 *p = buf+29+3;
ut8 *p = buf + 32;
st32 maindelta = p[0] | p[1]<<8 | p[2]<<16 | p[3]<<24;
return (ut64)(entry + 29 + maindelta) + 7;
ut64 vmain = (ut64)(entry + 29 + maindelta) + 7;
ut64 ventry = Elf_(r_bin_elf_p2v) (bin, entry);
if (vmain>>16 == ventry>>16) {
return (ut64)vmain;
}
}
return 0;
/* find sym.main if possible */
{
ut64 main = getmainsymbol (bin);
if (main != UT64_MAX) {
return main;
}
}
return UT64_MAX;
}
int Elf_(r_bin_elf_get_stripped)(struct Elf_(r_bin_elf_obj_t) *bin) {
@ -1604,27 +1639,28 @@ if (
free (strtab);
return NULL;
}
nsym = (int)(bin->shdr[i].sh_size/sizeof (Elf_(Sym)));
nsym = (int)(bin->shdr[i].sh_size / sizeof (Elf_(Sym)));
if (nsym < 1){
free (ret);
free (strtab);
return NULL;
}
if ((sym = (Elf_(Sym) *)calloc (nsym, sizeof(Elf_(Sym)))) == NULL) {
if (!(sym = (Elf_(Sym) *)calloc (nsym, sizeof (Elf_(Sym))))) {
eprintf ("calloc (syms)");
free (ret);
free (strtab);
return NULL;
}
if (!UT32_MUL (&size, nsym, sizeof (Elf_(Sym)))){
if (!UT32_MUL (&size, nsym, sizeof (Elf_(Sym)))) {
free (ret);
free (strtab);
free (sym);
return NULL;
}
if (size < 1 || size > bin->size ||
bin->shdr[i].sh_offset > bin->size || bin->shdr[i].sh_offset+size > bin->size){
bin->shdr[i].sh_offset > bin->size ||
bin->shdr[i].sh_offset+size > bin->size) {
free (ret);
free (strtab);
free (sym);

2
libr/bin/p/bin_elf.c
View File

@ -86,7 +86,7 @@ static RBinAddr* binsym(RBinFile *arch, int sym) {
addr = Elf_(r_bin_elf_get_fini_offset) (arch->o->bin_obj);
break;
}
if (addr && (ret = R_NEW0 (RBinAddr))) {
if (addr && addr!= UT64_MAX && (ret = R_NEW0 (RBinAddr))) {
ret->paddr = addr;
ret->vaddr = Elf_(r_bin_elf_p2v) (obj, addr);
}