diff options
Diffstat (limited to 'lib/hook-functions.c')
| -rw-r--r-- | lib/hook-functions.c | 58 |
1 files changed, 29 insertions, 29 deletions
diff --git a/lib/hook-functions.c b/lib/hook-functions.c index 953683b..7db06d4 100644 --- a/lib/hook-functions.c +++ b/lib/hook-functions.c @@ -77,6 +77,8 @@ static int check_intro_trampoline(void **trampoline_ptr_p, if (*patch_size_p != -1) return SUBSTITUTE_OK; + *need_intro_trampoline_p = true; + /* Try existing trampoline */ *patch_size_p = jump_patch_size(pc, (uintptr_t) trampoline_ptr, arch, false); @@ -122,8 +124,7 @@ skip_after:; EXPORT int substitute_hook_functions(const struct substitute_function_hook *hooks, - size_t nhooks, - int options) { + size_t nhooks, int options) { struct hook_internal *his = malloc(nhooks * sizeof(*his)); if (!his) return SUBSTITUTE_ERR_OOM; @@ -169,20 +170,6 @@ int substitute_hook_functions(const struct substitute_function_hook *hooks, goto end; uint_tptr pc_patch_end = pc_patch_start + patch_size; - /* Generate the rewritten start of the function for the outro - * trampoline (complaining if any bad instructions are found) - * (on arm64, this modifies regs_possibly_written, which is used by the - * two make_jump_patch calls) */ - uint8_t rewritten_temp[TD_MAX_REWRITTEN_SIZE]; - void *rp = rewritten_temp; - if ((ret = transform_dis_main(code, &rp, pc_patch_start, &pc_patch_end, - &arch, hi->offset_by_pcdiff))) - goto end; - /* Check some of the rest of the function for jumps back into the - * patched region. */ - if ((ret = jump_dis_main(code, pc_patch_start, pc_patch_end, arch))) - goto end; - uintptr_t initial_target; if (need_intro_trampoline) { initial_target = (uintptr_t) trampoline_ptr; @@ -191,26 +178,26 @@ int substitute_hook_functions(const struct substitute_function_hook *hooks, } else { initial_target = (uintptr_t) hook->replacement; } + + /* Make the real jump patch for the target function. */ void *jp = hi->jump_patch; make_jump_patch(&jp, pc_patch_start, initial_target, arch); hi->jump_patch_size = (uint8_t *) jp - hi->jump_patch; + size_t align_bytes = (-(uintptr_t) trampoline_ptr) + & (arch_code_alignment(arch) - 1); + size_t outro_est = align_bytes + + TD_MAX_REWRITTEN_SIZE + MAX_JUMP_PATCH_SIZE; - size_t rewritten_size = (uint8_t *) rp - rewritten_temp; - size_t jumpback_size = - jump_patch_size((uintptr_t) trampoline_ptr + rewritten_size, - pc_patch_end, arch, /* force */ true); - size_t outro_size = rewritten_size + jumpback_size; - if (outro_size > trampoline_size_left) { + if (outro_est > trampoline_size_left) { /* Not enough space left in our existing block... */ if ((ret = execmem_alloc_unsealed(0, &trampoline_ptr, &trampoline_size_left))) goto end; hi->trampoline_page = trampoline_ptr; - jumpback_size = - jump_patch_size((uintptr_t) trampoline_ptr + rewritten_size, - pc_patch_end, arch, /* force */ true); - outro_size = rewritten_size + jumpback_size; + } else { + trampoline_ptr += align_bytes; + trampoline_size_left -= align_bytes; } hi->outro_trampoline = trampoline_ptr; @@ -221,10 +208,23 @@ int substitute_hook_functions(const struct substitute_function_hook *hooks, dpc++; } #endif - memcpy(trampoline_ptr, rewritten_temp, rewritten_size); - trampoline_ptr += rewritten_size; + /* Generate the rewritten start of the function for the outro + * trampoline (complaining if any bad instructions are found) + * (on arm64, this modifies regs_possibly_written, which is used by the + * ending make_jump_patch call) */ + if ((ret = transform_dis_main(code, &trampoline_ptr, pc_patch_start, + &pc_patch_end, (uintptr_t) trampoline_ptr, + &arch, hi->offset_by_pcdiff))) + goto end; + /* Now that transform_dis_main has given us the final pc_patch_end, + * check some of the rest of the function for jumps back into the + * patched region. */ + if ((ret = jump_dis_main(code, pc_patch_start, pc_patch_end, arch))) + goto end; + /* Okay, continue with the outro. */ make_jump_patch(&trampoline_ptr, (uintptr_t) trampoline_ptr, dpc, arch); - trampoline_size_left -= outro_size; + trampoline_size_left -= (uint8_t *) trampoline_ptr + - (uint8_t *) hi->outro_trampoline; } /* Now commit. */ |