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Working ASLR implementation

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Separate files for retouch functionality are in minelf/*

ASLR for shared libraries is controlled by "-a" in ota_from_target_files.
Binary files are self-contained. Retouch logic can recover from crashes.

Signed-off-by: Hristo Bojinov <hristo@google.com>
Change-Id: I76c596abf4febd68c14f9d807ac62e8751e0b1bd
This commit is contained in:
Hristo Bojinov
2010-08-02 14:17:33 -07:00
parent f635d2e910
commit db314d69f0
10 changed files with 649 additions and 18 deletions
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applypatch/applypatch.c
+32 -10
View File
@@ -30,16 +30,21 @@
#include "mtdutils/mtdutils.h"
#include "edify/expr.h"
static int SaveFileContents(const char* filename, FileContents file);
int SaveFileContents(const char* filename, FileContents file);
static int LoadPartitionContents(const char* filename, FileContents* file);
int ParseSha1(const char* str, uint8_t* digest);
static ssize_t FileSink(unsigned char* data, ssize_t len, void* token);
static int mtd_partitions_scanned = 0;
// Read a file into memory; store it and its associated metadata in
// *file. Return 0 on success.
int LoadFileContents(const char* filename, FileContents* file) {
// Read a file into memory; optionally (retouch_flag == RETOUCH_DO_MASK) mask
// the retouched entries back to their original value (such that SHA-1 checks
// don't fail due to randomization); store the file contents and associated
// metadata in *file.
//
// Return 0 on success.
int LoadFileContents(const char* filename, FileContents* file,
int retouch_flag) {
file->data = NULL;
// A special 'filename' beginning with "MTD:" or "EMMC:" means to
@@ -75,6 +80,20 @@ int LoadFileContents(const char* filename, FileContents* file) {
}
fclose(f);
// apply_patch[_check] functions are blind to randomization. Randomization
// is taken care of in [Undo]RetouchBinariesFn. If there is a mismatch
// within a file, this means the file is assumed "corrupt" for simplicity.
if (retouch_flag) {
int32_t desired_offset = 0;
if (retouch_mask_data(file->data, file->size,
&desired_offset, NULL) != RETOUCH_DATA_MATCHED) {
printf("error trying to mask retouch entries\n");
free(file->data);
file->data = NULL;
return -1;
}
}
SHA(file->data, file->size, file->sha1);
return 0;
}
@@ -303,7 +322,7 @@ static int LoadPartitionContents(const char* filename, FileContents* file) {
// Save the contents of the given FileContents object under the given
// filename. Return 0 on success.
static int SaveFileContents(const char* filename, FileContents file) {
int SaveFileContents(const char* filename, FileContents file) {
int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC);
if (fd < 0) {
printf("failed to open \"%s\" for write: %s\n",
@@ -477,7 +496,7 @@ int applypatch_check(const char* filename,
// LoadFileContents is successful. (Useful for reading
// partitions, where the filename encodes the sha1s; no need to
// check them twice.)
if (LoadFileContents(filename, &file) != 0 ||
if (LoadFileContents(filename, &file, RETOUCH_DO_MASK) != 0 ||
(num_patches > 0 &&
FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) {
printf("file \"%s\" doesn't have any of expected "
@@ -491,7 +510,7 @@ int applypatch_check(const char* filename,
// exists and matches the sha1 we're looking for, the check still
// passes.
if (LoadFileContents(CACHE_TEMP_SOURCE, &file) != 0) {
if (LoadFileContents(CACHE_TEMP_SOURCE, &file, RETOUCH_DO_MASK) != 0) {
printf("failed to load cache file\n");
return 1;
}
@@ -617,7 +636,8 @@ int applypatch(const char* source_filename,
int made_copy = 0;
// We try to load the target file into the source_file object.
if (LoadFileContents(target_filename, &source_file) == 0) {
if (LoadFileContents(target_filename, &source_file,
RETOUCH_DO_MASK) == 0) {
if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) {
// The early-exit case: the patch was already applied, this file
// has the desired hash, nothing for us to do.
@@ -633,7 +653,8 @@ int applypatch(const char* source_filename,
// Need to load the source file: either we failed to load the
// target file, or we did but it's different from the source file.
free(source_file.data);
LoadFileContents(source_filename, &source_file);
LoadFileContents(source_filename, &source_file,
RETOUCH_DO_MASK);
}
if (source_file.data != NULL) {
@@ -648,7 +669,8 @@ int applypatch(const char* source_filename,
free(source_file.data);
printf("source file is bad; trying copy\n");
if (LoadFileContents(CACHE_TEMP_SOURCE, &copy_file) < 0) {
if (LoadFileContents(CACHE_TEMP_SOURCE, &copy_file,
RETOUCH_DO_MASK) < 0) {
// fail.
printf("failed to read copy file\n");
return 1;