idevicebackup: verify all backup files when restoring

1 files changed, 241 insertions, 2 deletions

diff --git a/tools/idevicebackup.c b/tools/idevicebackup.c
index 15b8d05..0a7fd70 100644
--- a/tools/idevicebackup.c
+++ b/tools/idevicebackup.c
@@ -76,6 +76,62 @@ static int compare_hash(const unsigned char *hash1, const unsigned char *hash2,
         return 1;
 }
 
+static void compute_datahash(const char *path, const char *destpath, uint8_t greylist, const char *domain, const char *appid, const char *version, unsigned char *hash_out)
+{
+        gcry_md_hd_t hd = NULL;
+        gcry_md_open(&hd, GCRY_MD_SHA1, 0);
+        if (!hd) {
+                printf("ERROR: Could not initialize libgcrypt/SHA1\n");
+                return;
+        }
+        gcry_md_reset(hd);
+
+        FILE *f = fopen(path, "rb");
+        if (f) {
+                unsigned char buf[16384];
+                size_t len;
+                while ((len = fread(buf, 1, 16384, f)) > 0) {
+                        gcry_md_write(hd, buf, len);
+                }
+                fclose(f);
+                gcry_md_write(hd, destpath, strlen(destpath));
+                gcry_md_write(hd, ";", 1);
+                if (greylist == 1) {
+                        gcry_md_write(hd, "true", 4);
+                } else {
+                        gcry_md_write(hd, "false", 5);
+                }
+                gcry_md_write(hd, ";", 1);
+                if (domain) {
+                        gcry_md_write(hd, domain, strlen(domain));
+                } else {
+                        gcry_md_write(hd, "(null)", 6);
+                }
+                gcry_md_write(hd, ";", 1);
+                if (appid) {
+                        gcry_md_write(hd, appid, strlen(appid));
+                } else {
+                        gcry_md_write(hd, "(null)", 6);
+                }
+                gcry_md_write(hd, ";", 1);
+                if (version) {
+                        gcry_md_write(hd, version, strlen(version));
+                } else {
+                        gcry_md_write(hd, "(null)", 6);
+                }
+                unsigned char *newhash = gcry_md_read(hd, GCRY_MD_SHA1);
+                memcpy(hash_out, newhash, 20);
+        }
+        gcry_md_close(hd);
+}
+
+static void print_hash(const unsigned char *hash, int len)
+{
+        int i;
+        for (i = 0; i < len; i++) {
+                printf("%02x", hash[i]);
+        }
+}
 
 static void notify_cb(const char *notification, void *userdata)
 {
@@ -399,6 +455,157 @@ static int mobilebackup_delete_backup_file_by_hash(const char *backup_directory,
         return ret;
 }
 
+static int mobilebackup_check_file_integrity(const char *backup_directory, const char *hash, plist_t filedata)
+{
+        char *datapath;
+        char *infopath;
+        plist_t mdinfo = NULL;
+        struct stat st;
+        unsigned char file_hash[20];
+
+        datapath = mobilebackup_build_path(backup_directory, hash, ".mddata");
+        if (stat(datapath, &st) != 0) {
+                printf("\r\n");
+                printf("ERROR: '%s.mddata' is missing!\n", hash);
+                free(datapath);
+                return 0;
+        }
+
+        infopath = mobilebackup_build_path(backup_directory, hash, ".mdinfo");
+        plist_read_from_filename(&mdinfo, infopath);
+        free(infopath);
+        if (!mdinfo) {
+                printf("\r\n");
+                printf("ERROR: '%s.mdinfo' is missing or corrupted!\n", hash);
+                free(datapath);
+                return 0;
+        }
+
+        /* sha1 hash verification */
+        plist_t node = plist_dict_get_item(filedata, "DataHash");
+        if (!node || (plist_get_node_type(node) != PLIST_DATA)) {
+                printf("\r\n");
+                printf("ERROR: Could not get DataHash for file entry '%s'\n", hash);
+                plist_free(mdinfo);
+                free(datapath);
+                return 0;
+        }
+
+        node = plist_dict_get_item(mdinfo, "Metadata");
+        if (!node && (plist_get_node_type(node) != PLIST_DATA)) {
+                printf("\r\n");
+                printf("ERROR: Could not find Metadata in plist '%s.mdinfo'\n", hash);
+                plist_free(mdinfo);
+                free(datapath);
+                return 0;
+        }
+
+        char *meta_bin = NULL;
+        uint64_t meta_bin_size = 0;
+        plist_get_data_val(node, &meta_bin, &meta_bin_size);
+        plist_t metadata = NULL;
+        if (meta_bin) {
+                plist_from_bin(meta_bin, (uint32_t)meta_bin_size, &metadata);
+        }
+        if (!metadata) {
+                printf("\r\n");
+                printf("ERROR: Could not get Metadata from plist '%s.mdinfo'\n", hash);
+                plist_free(mdinfo);
+                free(datapath);
+                return 0;
+        }
+
+        char *version = NULL;
+        node = plist_dict_get_item(metadata, "Version");
+        if (node && (plist_get_node_type(node) == PLIST_STRING)) { 
+                plist_get_string_val(node, &version);
+        }
+
+        char *destpath = NULL;
+        node = plist_dict_get_item(metadata, "Path");
+        if (node && (plist_get_node_type(node) == PLIST_STRING)) { 
+                plist_get_string_val(node, &destpath);
+        }
+
+        uint8_t greylist = 0;
+        node = plist_dict_get_item(metadata, "Greylist");
+        if (node && (plist_get_node_type(node) == PLIST_BOOLEAN)) {
+                plist_get_bool_val(node, &greylist);
+        }
+
+        char *domain = NULL;
+        node = plist_dict_get_item(metadata, "Domain");
+        if (node && (plist_get_node_type(node) == PLIST_STRING)) { 
+                plist_get_string_val(node, &domain);
+        }
+
+        char *fnstr = malloc(strlen(domain) + 1 + strlen(destpath) + 1);
+        strcpy(fnstr, domain);
+        strcat(fnstr, "-");
+        strcat(fnstr, destpath);
+        unsigned char fnhash[20];
+        char fnamehash[41];
+        char *p = fnamehash;
+        sha1_of_data(fnstr, strlen(fnstr), fnhash);
+        free(fnstr);
+        int i;
+        for ( i = 0; i < 20; i++, p += 2 ) {
+                snprintf (p, 3, "%02x", (unsigned char)fnhash[i] );
+        }
+        if (strcmp(fnamehash, hash)) {
+                printf("\r\n"); 
+                printf("WARNING: filename hash does not match for entry '%s'\n", hash);
+        }
+
+        char *auth_version = NULL;
+        node = plist_dict_get_item(mdinfo, "AuthVersion");
+        if (node && (plist_get_node_type(node) == PLIST_STRING)) {
+                plist_get_string_val(node, &auth_version);
+        }
+
+        if (strcmp(auth_version, "1.0")) {
+                printf("\r\n");
+                printf("WARNING: Unknown AuthVersion '%s', DataHash cannot be verified!\n", auth_version);
+        }
+
+        node = plist_dict_get_item(filedata, "DataHash");
+        if (!node || (plist_get_node_type(node) != PLIST_DATA)) {
+                printf("\r\n");
+                printf("WARNING: Could not get DataHash key from file info data for entry '%s'\n", hash);
+        }
+
+        int res = 1;
+        unsigned char *data_hash = NULL;
+        uint64_t data_hash_len = 0;
+        plist_get_data_val(node, (char**)&data_hash, &data_hash_len);
+        int hash_ok = 0;
+        if (data_hash && (data_hash_len == 20)) {
+                compute_datahash(datapath, destpath, greylist, domain, NULL, version, file_hash);
+                hash_ok = compare_hash(data_hash, file_hash, 20);
+        } else if (data_hash_len == 0) {
+                /* no datahash present */
+                hash_ok = 1;
+        }
+
+        g_free(domain);
+        g_free(version);
+        g_free(destpath);
+
+        if (!hash_ok) {
+                printf("\r\n");
+                printf("ERROR: The hash for '%s.mddata' does not match DataHash entry in Manifest\n", hash);
+                printf("datahash: ");
+                print_hash(data_hash, 20);
+                printf("\nfilehash: ");
+                print_hash(file_hash, 20);
+                printf("\n");
+                res = 0;
+        }
+        g_free(data_hash);
+        plist_free(mdinfo);
+        return res;
+}
+
 static void do_post_notification(const char *notification)
 {
         uint16_t nport = 0;
@@ -983,8 +1190,40 @@ int main(int argc, char *argv[])
                                 printf("Could not read plist from Manifest.plist Data key!\n");
                                 break;
                         }
-                                /* loop over Files entries in Manifest data plist */
-                                        /* make sure both .mddata/.mdinfo files are available for each entry */
+                        plist_t files = plist_dict_get_item(backup_data, "Files");
+                        if (files && (plist_get_node_type(files) == PLIST_DICT)) {
+                                plist_dict_iter iter = NULL;
+                                plist_dict_new_iter(files, &iter);
+                                if (iter) {
+                                        /* loop over Files entries in Manifest data plist */
+                                        char *hash = NULL;
+                                        int file_ok = 0;
+                                        int total_files = plist_dict_get_size(files);
+                                        int cur_file = 1;
+                                        node = NULL;
+                                        plist_dict_next_item(files, iter, &hash, &node);
+                                        while (node) {
+                                                printf("Verifying files %d/%d (%d%%) \r", cur_file, total_files, (cur_file*100/total_files));
+                                                cur_file++;
+                                                /* make sure both .mddata/.mdinfo files are available for each entry */
+                                                file_ok = mobilebackup_check_file_integrity(backup_directory, hash, node);
+                                                node = NULL;
+                                                free(hash);
+                                                hash = NULL;
+                                                if (!file_ok) {
+                                                        break;
+                                                }
+                                                plist_dict_next_item(files, iter, &hash, &node);
+                                        }
+                                        printf("\n");
+                                        free(iter);
+                                        if (!file_ok) {
+                                                plist_free(backup_data);
+                                                break;
+                                        }
+                                        printf("All backup files appear to be valid\n");
+                                }
+                        }
                         /* request restore from device with manifest (BackupMessageRestoreMigrate) */
                         /* loop over Files entries in Manifest data plist */
                                 /* read mddata/mdinfo files and send to device using DLSendFile */