From a1bc148c7c81f886426c253f2ea7beb0f301f6b0 Mon Sep 17 00:00:00 2001 From: Doug Zongker Date: Thu, 13 Feb 2014 15:18:19 -0800 Subject: remove 'retouch' ASLR support Older versions of android supported an ASLR system where binaries were randomly twiddled at OTA install time. Remove support for this; we now use the ASLR support in the linux kernel. Change-Id: I8348eb0d6424692668dc1a00e2416fbef6c158a2 --- minelf/Retouch.c | 196 ------------------------------------------------------- 1 file changed, 196 deletions(-) delete mode 100644 minelf/Retouch.c (limited to 'minelf/Retouch.c') diff --git a/minelf/Retouch.c b/minelf/Retouch.c deleted file mode 100644 index d75eec1e8..000000000 --- a/minelf/Retouch.c +++ /dev/null @@ -1,196 +0,0 @@ -/* - * Copyright (C) 2009 The Android Open Source Project - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -#include -#include -#include -#include -#include -#include -#include -#include "Retouch.h" -#include "applypatch/applypatch.h" - -typedef struct { - int32_t mmap_addr; - char tag[4]; /* 'P', 'R', 'E', ' ' */ -} prelink_info_t __attribute__((packed)); - -#define false 0 -#define true 1 - -static int32_t offs_prev; -static uint32_t cont_prev; - -static void init_compression_state(void) { - offs_prev = 0; - cont_prev = 0; -} - -// For details on the encoding used for relocation lists, please -// refer to build/tools/retouch/retouch-prepare.c. The intent is to -// save space by removing most of the inherent redundancy. - -static void decode_bytes(uint8_t *encoded_bytes, int encoded_size, - int32_t *dst_offset, uint32_t *dst_contents) { - if (encoded_size == 2) { - *dst_offset = offs_prev + (((encoded_bytes[0]&0x60)>>5)+1)*4; - - // if the original was negative, we need to 1-pad before applying delta - int32_t tmp = (((encoded_bytes[0] & 0x0000001f) << 8) | - encoded_bytes[1]); - if (tmp & 0x1000) tmp = 0xffffe000 | tmp; - *dst_contents = cont_prev + tmp; - } else if (encoded_size == 3) { - *dst_offset = offs_prev + (((encoded_bytes[0]&0x30)>>4)+1)*4; - - // if the original was negative, we need to 1-pad before applying delta - int32_t tmp = (((encoded_bytes[0] & 0x0000000f) << 16) | - (encoded_bytes[1] << 8) | - encoded_bytes[2]); - if (tmp & 0x80000) tmp = 0xfff00000 | tmp; - *dst_contents = cont_prev + tmp; - } else { - *dst_offset = - (encoded_bytes[0]<<24) | - (encoded_bytes[1]<<16) | - (encoded_bytes[2]<<8) | - encoded_bytes[3]; - if (*dst_offset == 0x3fffffff) *dst_offset = -1; - *dst_contents = - (encoded_bytes[4]<<24) | - (encoded_bytes[5]<<16) | - (encoded_bytes[6]<<8) | - encoded_bytes[7]; - } -} - -static uint8_t *decode_in_memory(uint8_t *encoded_bytes, - int32_t *offset, uint32_t *contents) { - int input_size, charIx; - uint8_t input[8]; - - input[0] = *(encoded_bytes++); - if (input[0] & 0x80) - input_size = 2; - else if (input[0] & 0x40) - input_size = 3; - else - input_size = 8; - - // we already read one byte.. - charIx = 1; - while (charIx < input_size) { - input[charIx++] = *(encoded_bytes++); - } - - // depends on the decoder state! - decode_bytes(input, input_size, offset, contents); - - offs_prev = *offset; - cont_prev = *contents; - - return encoded_bytes; -} - -int retouch_mask_data(uint8_t *binary_object, - int32_t binary_size, - int32_t *desired_offset, - int32_t *retouch_offset) { - retouch_info_t *r_info; - prelink_info_t *p_info; - - int32_t target_offset = 0; - if (desired_offset) target_offset = *desired_offset; - - int32_t p_offs = binary_size-sizeof(prelink_info_t); // prelink_info_t - int32_t r_offs = p_offs-sizeof(retouch_info_t); // retouch_info_t - int32_t b_offs; // retouch data blob - - // If not retouched, we say it was a match. This might get invoked on - // non-retouched binaries, so that's why we need to do this. - if (retouch_offset != NULL) *retouch_offset = target_offset; - if (r_offs < 0) return (desired_offset == NULL) ? - RETOUCH_DATA_NOTAPPLICABLE : RETOUCH_DATA_MATCHED; - p_info = (prelink_info_t *)(binary_object+p_offs); - r_info = (retouch_info_t *)(binary_object+r_offs); - if (strncmp(p_info->tag, "PRE ", 4) || - strncmp(r_info->tag, "RETOUCH ", 8)) - return (desired_offset == NULL) ? - RETOUCH_DATA_NOTAPPLICABLE : RETOUCH_DATA_MATCHED; - - b_offs = r_offs-r_info->blob_size; - if (b_offs < 0) { - printf("negative binary offset: %d = %d - %d\n", - b_offs, r_offs, r_info->blob_size); - return RETOUCH_DATA_ERROR; - } - uint8_t *b_ptr = binary_object+b_offs; - - // Retouched: let's go through the work then. - int32_t offset_candidate = target_offset; - bool offset_set = false, offset_mismatch = false; - init_compression_state(); - while (b_ptr < (uint8_t *)r_info) { - int32_t retouch_entry_offset; - uint32_t *retouch_entry; - uint32_t retouch_original_value; - - b_ptr = decode_in_memory(b_ptr, - &retouch_entry_offset, - &retouch_original_value); - if (retouch_entry_offset < (-1) || - retouch_entry_offset >= b_offs) { - printf("bad retouch_entry_offset: %d", retouch_entry_offset); - return RETOUCH_DATA_ERROR; - } - - // "-1" means this is the value in prelink_info_t, which also gets - // randomized. - if (retouch_entry_offset == -1) - retouch_entry = (uint32_t *)&(p_info->mmap_addr); - else - retouch_entry = (uint32_t *)(binary_object+retouch_entry_offset); - - if (desired_offset) - *retouch_entry = retouch_original_value + target_offset; - - // Infer the randomization shift, compare to previously inferred. - int32_t offset_of_this_entry = (int32_t)(*retouch_entry- - retouch_original_value); - if (!offset_set) { - offset_candidate = offset_of_this_entry; - offset_set = true; - } else { - if (offset_candidate != offset_of_this_entry) { - offset_mismatch = true; - printf("offset is mismatched: %d, this entry is %d," - " original 0x%x @ 0x%x", - offset_candidate, offset_of_this_entry, - retouch_original_value, retouch_entry_offset); - } - } - } - if (b_ptr > (uint8_t *)r_info) { - printf("b_ptr went too far: %p, while r_info is %p", - b_ptr, r_info); - return RETOUCH_DATA_ERROR; - } - - if (offset_mismatch) return RETOUCH_DATA_MISMATCHED; - if (retouch_offset != NULL) *retouch_offset = offset_candidate; - return RETOUCH_DATA_MATCHED; -} -- cgit v1.2.3