Skip to content

Fix SubGetImageByName for iOS versions with ImageLoaderMegaDylib #28

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 2 commits into
base: master
Choose a base branch
from
Open

Fix SubGetImageByName for iOS versions with ImageLoaderMegaDylib #28

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f726a74
Fix SubGetImageByName for iOS versions with ImageLoaderMegaDylib (iOS…
sbingner Apr 13, 2018
6e3c212
Stop using x18 on arm64
rweichler Jul 16, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion lib/arm64/arch-dis.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ static inline void arch_dis_ctx_init(struct arch_dis_ctx *ctx) {
}

static inline int arm64_get_unwritten_temp_reg(struct arch_dis_ctx *ctx) {
uint32_t avail = ~ctx->regs_possibly_written & ((1 << 19) - (1 << 9));
uint32_t avail = ~ctx->regs_possibly_written & ((1 << 18) - (1 << 9));
if (!avail)
__builtin_abort();
return 31 - __builtin_clz(avail);
Expand Down
61 changes: 53 additions & 8 deletions lib/darwin/find-syms.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,12 +11,27 @@
#include "substitute-internal.h"
#include "dyld_cache_format.h"

extern const struct dyld_all_image_infos *_dyld_get_all_image_infos();
const struct dyld_all_image_infos *__dyld_get_all_image_infos() {
struct task_dyld_info dyld_info;
mach_msg_type_number_t count = TASK_DYLD_INFO_COUNT;
if (task_info(mach_task_self(), TASK_DYLD_INFO, (task_info_t)&dyld_info, &count) == KERN_SUCCESS) {
return (struct dyld_all_image_infos *)dyld_info.all_image_info_addr;
} else {
abort();
}
}
extern const struct dyld_all_image_infos *_dyld_get_all_image_infos() __attribute__((weak_import));
const struct dyld_all_image_infos *(*dyld_get_all_image_infos)();

static pthread_once_t dyld_inspect_once = PTHREAD_ONCE_INIT;
/* and its fruits: */
static uintptr_t (*ImageLoaderMachO_getSlide)(void *);
static const struct mach_header *(*ImageLoaderMachO_machHeader)(void *);
static bool (*dyld_validImage)(void *);
uintptr_t (*ImageLoaderMegaDylib_getSlide)(void*);
void *(*ImageLoaderMegaDylib_getIndexedMachHeader)(void*, unsigned index);
void *(*ImageLoaderMegaDylib_isCacheHandle)(void*proxy, void* handle, unsigned* index, uint8_t* flags);
void **dyld_sAllCacheImagesProxy;

static const struct dyld_cache_header *_Atomic s_cur_shared_cache_hdr;
static int s_cur_shared_cache_fd;
Expand Down Expand Up @@ -280,18 +295,26 @@ ok2: ;
*/

static void inspect_dyld() {
const struct dyld_all_image_infos *aii = _dyld_get_all_image_infos();
const struct dyld_all_image_infos *aii = dyld_get_all_image_infos();
const void *dyld_hdr = aii->dyldImageLoadAddress;

const char *names[2] = { "__ZNK16ImageLoaderMachO8getSlideEv",
"__ZNK16ImageLoaderMachO10machHeaderEv" };
void *syms[2];
const char *names[6] = { "__ZNK16ImageLoaderMachO8getSlideEv",
"__ZNK16ImageLoaderMachO10machHeaderEv",
"__ZN4dyldL20sAllCacheImagesProxyE",
"__ZN20ImageLoaderMegaDylib13isCacheHandleEPvPjPh",
"__ZNK20ImageLoaderMegaDylib8getSlideEv",
"__ZNK20ImageLoaderMegaDylib20getIndexedMachHeaderEj" };
void *syms[6];
intptr_t dyld_slide = -1;
find_syms_raw(dyld_hdr, &dyld_slide, names, syms, 2);
find_syms_raw(dyld_hdr, &dyld_slide, names, syms, 6);
if (!syms[0] || !syms[1])
substitute_panic("couldn't find ImageLoader methods\n");
ImageLoaderMachO_getSlide = syms[0];
ImageLoaderMachO_machHeader = syms[1];
dyld_sAllCacheImagesProxy = syms[2];
ImageLoaderMegaDylib_isCacheHandle = syms[3];
ImageLoaderMegaDylib_getSlide = syms[4];
ImageLoaderMegaDylib_getIndexedMachHeader = syms[5];
}

/* 'dlhandle' keeps the image alive */
Expand All @@ -303,8 +326,20 @@ struct substitute_image *substitute_open_image(const char *filename) {
if (!dlhandle)
return NULL;

const void *image_header = ImageLoaderMachO_machHeader(dlhandle);
intptr_t slide = ImageLoaderMachO_getSlide(dlhandle);
void* image = (void*)(((uintptr_t)dlhandle) & (-4));
unsigned index;
uint8_t mode;
const void *image_header;
intptr_t slide;
if (ImageLoaderMegaDylib_isCacheHandle != NULL && ImageLoaderMegaDylib_isCacheHandle(*dyld_sAllCacheImagesProxy, image, &index, &mode)) {
if (ImageLoaderMegaDylib_getSlide == NULL || ImageLoaderMegaDylib_getIndexedMachHeader == NULL)
substitute_panic("couldn't find ImageLoaderMegaDylib methods\n");
slide = ImageLoaderMegaDylib_getSlide(*dyld_sAllCacheImagesProxy);
image_header = ImageLoaderMegaDylib_getIndexedMachHeader(*dyld_sAllCacheImagesProxy, index);
} else {
image_header = ImageLoaderMachO_machHeader(image);
slide = ImageLoaderMachO_getSlide(image);
}

struct substitute_image *im = malloc(sizeof(*im));
if (!im)
Expand All @@ -330,4 +365,14 @@ int substitute_find_private_syms(struct substitute_image *im,
return SUBSTITUTE_OK;
}


__attribute__((constructor))
void init(void) {
if (_dyld_get_all_image_infos != NULL) {
fprintf(stderr, "_dyld_get_all_image_infos present\n");
dyld_get_all_image_infos = _dyld_get_all_image_infos;
} else {
dyld_get_all_image_infos = __dyld_get_all_image_infos;
}
}
#endif /* __APPLE__ */