sbtools: be more verbose on real key and iv; add very advanced code to craft images

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30835 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 65 insertions, 9 deletions

diff --git a/utils/sbtools/elftosb.c b/utils/sbtools/elftosb.c
index 986376179a..17b72417cf 100644
--- a/utils/sbtools/elftosb.c
+++ b/utils/sbtools/elftosb.c
@@ -773,6 +773,7 @@ static void produce_sb_file(struct sb_file_t *sb, const char *filename)
         bugp("cannot open output file");
 
     byte real_key[16];
+    byte crypto_iv[16];
     byte (*cbc_macs)[16] = xmalloc(16 * g_nr_keys);
     /* init CBC-MACs */
     for(int i = 0; i < g_nr_keys; i++)
@@ -791,6 +792,9 @@ static void produce_sb_file(struct sb_file_t *sb, const char *filename)
     produce_sb_header(sb, &sb_hdr);
     sha_1_update(&file_sha1, (byte *)&sb_hdr, sizeof(sb_hdr));
     write(fd, &sb_hdr, sizeof(sb_hdr));
+    
+    memcpy(crypto_iv, &sb_hdr, 16);
+
     /* update CBC-MACs */
     for(int i = 0; i < g_nr_keys; i++)
         cbc_mac((byte *)&sb_hdr, NULL, sizeof(sb_hdr) / BLOCK_SIZE, g_key_array[i],
@@ -814,11 +818,53 @@ static void produce_sb_file(struct sb_file_t *sb, const char *filename)
         struct sb_key_dictionary_entry_t entry;
         memcpy(entry.hdr_cbc_mac, cbc_macs[i], 16);
         cbc_mac(real_key, entry.key, sizeof(real_key) / BLOCK_SIZE, g_key_array[i],
-            (byte *)&sb_hdr, NULL, 1);
+            crypto_iv, NULL, 1);
         
         write(fd, &entry, sizeof(entry));
         sha_1_update(&file_sha1, (byte *)&entry, sizeof(entry));
     }
+
+    /* HACK HACK HACK HACK HACK HACK HACK HACK HACK HACK HACK HACK HACK HACK */
+    /* Image crafting, don't use it unless you understand what you do */
+    if(strlen(s_getenv("SB_OVERRIDE_REAL_KEY")) != 0)
+    {
+        const char *key = s_getenv("SB_OVERRIDE_REAL_KEY");
+        if(strlen(key) != 32)
+            bugp("Cannot override real key: invalid key length\n");
+        for(int i = 0; i < 16; i++)
+        {
+            byte a, b;
+            if(convxdigit(key[2 * i], &a) || convxdigit(key[2 * i + 1], &b))
+            bugp("Cannot override real key: key should be a 128-bit key written in hexadecimal\n");
+            real_key[i] = (a << 4) | b;
+        }
+    }
+    if(strlen(s_getenv("SB_OVERRIDE_IV")) != 0)
+    {
+        const char *iv = s_getenv("SB_OVERRIDE_IV");
+        if(strlen(iv) != 32)
+            bugp("Cannot override iv: invalid key length\n");
+        for(int i = 0; i < 16; i++)
+        {
+            byte a, b;
+            if(convxdigit(iv[2 * i], &a) || convxdigit(iv[2 * i + 1], &b))
+            bugp("Cannot override iv: key should be a 128-bit key written in hexadecimal\n");
+            crypto_iv[i] = (a << 4) | b;
+        }
+        
+    }
+    /* KCAH KCAH KCAH KCAH KCAH KCAH KCAH KCAH KCAH KCAH KCAH KCAH KCAH KCAH */
+    if(g_debug)
+    {
+        printf("Real key: ");
+        for(int j = 0; j < 16; j++)
+            printf("%02x", real_key[j]);
+        printf("\n");
+        printf("IV      : ");
+        for(int j = 0; j < 16; j++)
+            printf("%02x", crypto_iv[j]);
+        printf("\n");
+    }
     /* produce sections data */
     for(int i = 0; i< sb_hdr.nr_sections; i++)
     {
@@ -827,12 +873,12 @@ static void produce_sb_file(struct sb_file_t *sb, const char *filename)
         produce_section_tag_cmd(&sb->sections[i], &tag_cmd, (i + 1) == sb_hdr.nr_sections);
         if(g_nr_keys > 0)
             cbc_mac((byte *)&tag_cmd, (byte *)&tag_cmd, sizeof(tag_cmd) / BLOCK_SIZE,
-                real_key, (byte *)&sb_hdr, NULL, 1);
+                real_key, crypto_iv, NULL, 1);
         sha_1_update(&file_sha1, (byte *)&tag_cmd, sizeof(tag_cmd));
         write(fd, &tag_cmd, sizeof(tag_cmd));
         /* produce other commands */
         byte cur_cbc_mac[16];
-        memcpy(cur_cbc_mac, (byte *)&sb_hdr, 16);
+        memcpy(cur_cbc_mac, crypto_iv, 16);
         for(int j = 0; j < sb->sections[i].nr_insts; j++)
         {
             struct sb_inst_t *inst = &sb->sections[i].insts[j];
@@ -869,7 +915,7 @@ static void produce_sb_file(struct sb_file_t *sb, const char *filename)
     sha_1_output(&file_sha1, final_sig);
     generate_random_data(final_sig + 20, 12);
     if(g_nr_keys > 0)
-        cbc_mac(final_sig, final_sig, 2, real_key, (byte *)&sb_hdr, NULL, 1);
+        cbc_mac(final_sig, final_sig, 2, real_key, crypto_iv, NULL, 1);
     write(fd, final_sig, 32);
     
     close(fd);
diff --git a/utils/sbtools/sbtoelf.c b/utils/sbtools/sbtoelf.c
index 66deb6c0ab..fb4567bed9 100644
--- a/utils/sbtools/sbtoelf.c
+++ b/utils/sbtools/sbtoelf.c
@@ -372,8 +372,10 @@ static void extract(unsigned long filesize)
 
     if(memcmp(sb_header->signature, "STMP", 4) != 0)
         bugp("Bad signature");
+    /*
     if(sb_header->image_size * BLOCK_SIZE > filesize)
         bugp("File size mismatch");
+    */
     if(sb_header->header_size * BLOCK_SIZE != sizeof(struct sb_header_t))
         bugp("Bad header size");
     if(sb_header->sec_hdr_size * BLOCK_SIZE != sizeof(struct sb_section_header_t))
@@ -555,6 +557,17 @@ static void extract(unsigned long filesize)
         }
     }
 
+    color(RED);
+    printf("  Summary:\n");
+    color(GREEN);
+    printf("    Real key: ");
+    color(YELLOW);
+    print_hex(real_key, 16, true);
+    color(GREEN);
+    printf("    IV      : ");
+    color(YELLOW);
+    print_hex(g_buf, 16, true);
+
     /* sections */
     if(strcasecmp(s_getenv("SB_RAW_CMD"), "YES") != 0)
     {
@@ -615,10 +628,11 @@ static void extract(unsigned long filesize)
         printf("Commands\n");
         uint32_t offset = sb_header->first_boot_tag_off * BLOCK_SIZE;
         byte iv[16];
-        memcpy(iv, g_buf, 16);
         const char *indent = "    ";
         while(true)
         {
+            /* restart with IV */
+            memcpy(iv, g_buf, 16);
             byte cmd[BLOCK_SIZE];
             if(sb_header->nr_keys > 0)
                 cbc_mac(g_buf + offset, cmd, 1, real_key, iv, &iv, 0);
@@ -638,8 +652,6 @@ static void extract(unsigned long filesize)
                 color(RED);
                 printf("NOOP\n");
                 offset += BLOCK_SIZE;
-                /* restart with IV */
-                memcpy(iv, g_buf, 16);
             }
             else if(hdr->opcode == SB_INST_TAG)
             {
@@ -712,8 +724,6 @@ static void extract(unsigned long filesize)
                 if(tag->hdr.flags & SB_INST_LAST_TAG)
                     break;
                 offset += size;
-                /* restart with IV */
-                memcpy(iv, g_buf, 16);
             }
             else
             {