trezorhal: use const where possible for flash

embed/trezorhal/flash.c

@@ -13,7 +13,7 @@
 
 // see docs/memory.md for more information
 
-const uint32_t FLASH_SECTOR_TABLE[FLASH_SECTOR_COUNT + 1] = {
+static const uint32_t FLASH_SECTOR_TABLE[FLASH_SECTOR_COUNT + 1] = {
     [ 0] = 0x08000000, // - 0x08003FFF |  16 KiB
     [ 1] = 0x08004000, // - 0x08007FFF |  16 KiB
     [ 2] = 0x08008000, // - 0x0800BFFF |  16 KiB
@@ -66,7 +66,7 @@ const void *flash_get_address(uint8_t sector, uint32_t offset, uint32_t size)
     }
     uint32_t addr = FLASH_SECTOR_TABLE[sector];
     uint32_t next = FLASH_SECTOR_TABLE[sector + 1];
-    if (offset + size > next - addr) {
+    if (addr + offset + size > next) {
         return NULL;
     }
     return (const uint8_t *)addr + offset;
@@ -92,7 +92,7 @@ secbool flash_erase_sectors(const uint8_t *sectors, int len, void (*progress)(in
             return secfalse;
         }
         // check whether the sector was really deleted (contains only 0xFF)
-        uint32_t addr_start = FLASH_SECTOR_TABLE[sectors[i]], addr_end = FLASH_SECTOR_TABLE[sectors[i] + 1];
+        const uint32_t addr_start = FLASH_SECTOR_TABLE[sectors[i]], addr_end = FLASH_SECTOR_TABLE[sectors[i] + 1];
         for (uint32_t addr = addr_start; addr < addr_end; addr += 4) {
             if (*((const uint32_t *)addr) != 0xFFFFFFFF) {
                 flash_lock();
@@ -135,7 +135,7 @@ secbool flash_read_word_rel(uint8_t sector, uint32_t offset, uint32_t *data)
     if (offset % 4 != 0) {
         return secfalse;
     }
-    *data = *((uint32_t *) FLASH_SECTOR_TABLE[sector] + offset);
+    *data = *((const uint32_t *)FLASH_SECTOR_TABLE[sector] + offset);
     return sectrue;
 }
 

embed/trezorhal/flash.h

@@ -43,8 +43,6 @@
 // note: FLASH_SR_RDERR is STM32F42xxx and STM32F43xxx specific (STM32F427) (reference RM0090 section 3.7.5)
 #define FLASH_STATUS_ALL_FLAGS (FLASH_SR_RDERR | FLASH_SR_PGSERR | FLASH_SR_PGPERR | FLASH_SR_PGAERR | FLASH_SR_WRPERR | FLASH_SR_SOP | FLASH_SR_EOP)
 
-extern const uint32_t FLASH_SECTOR_TABLE[FLASH_SECTOR_COUNT + 1];
-
 secbool flash_init(void);
 
 secbool flash_unlock(void);

embed/trezorhal/image.c

@@ -144,7 +144,10 @@ secbool check_image_contents(const image_header * const hdr, uint32_t firstskip,
     if (0 == sectors || blocks < 1) {
         return secfalse;
     }
-    const void *data = (const void *)(FLASH_SECTOR_TABLE[sectors[0]] + firstskip);
+    const void *data = flash_get_address(sectors[0], firstskip, IMAGE_CHUNK_SIZE - firstskip);
+    if (!data) {
+        return secfalse;
+    }
     int remaining = hdr->codelen;
     if (sectrue != check_single_hash(hdr->hashes, data, MIN(remaining, IMAGE_CHUNK_SIZE - firstskip))) {
         return secfalse;
@@ -155,7 +158,10 @@ secbool check_image_contents(const image_header * const hdr, uint32_t firstskip,
         if (block >= blocks) {
             return secfalse;
         }
-        data = (const void *)FLASH_SECTOR_TABLE[sectors[block]];
+        data = flash_get_address(sectors[block], 0, IMAGE_CHUNK_SIZE);
+        if (!data) {
+            return secfalse;
+        }
         if (sectrue != check_single_hash(hdr->hashes + block * 32, data, MIN(remaining, IMAGE_CHUNK_SIZE))) {
             return secfalse;
         }

embed/unix/flash.c

@@ -86,11 +86,11 @@ const void *flash_get_address(uint8_t sector, uint32_t offset, uint32_t size)
     if (sector >= SECTOR_COUNT) {
         return NULL;
     }
-    uint32_t sector_size = sector_table[sector + 1] - sector_table[sector];
+    const uint32_t sector_size = sector_table[sector + 1] - sector_table[sector];
     if (offset + size > sector_size) {
         return NULL;
     }
-    uint32_t sector_offset = sector_table[sector] - sector_table[0];
+    const uint32_t sector_offset = sector_table[sector] - sector_table[0];
     return flash_buffer + sector_offset + offset;
 }
 
@@ -100,9 +100,9 @@ secbool flash_erase_sectors(const uint8_t *sectors, int len, void (*progress)(in
         progress(0, len);
     }
     for (int i = 0; i < len; i++) {
-        uint8_t sector = sectors[i];
-        uint32_t offset = sector_table[sector] - sector_table[0];
-        uint32_t size = sector_table[sector + 1] - sector_table[sector];
+        const uint8_t sector = sectors[i];
+        const uint32_t offset = sector_table[sector] - sector_table[0];
+        const uint32_t size = sector_table[sector + 1] - sector_table[sector];
         memset(flash_buffer + offset, 0xFF, size);
         if (progress) {
             progress(i + 1, len);
@@ -148,7 +148,7 @@ secbool flash_read_word_rel(uint8_t sector, uint32_t offset, uint32_t *data)
     if (offset % 4) {  // we read only at 4-byte boundary
         return secfalse;
     }
-    uint32_t *flash = (uint32_t *)flash_get_address(sector, offset, sizeof(data));
+    const uint32_t *flash = (const uint32_t *)flash_get_address(sector, offset, sizeof(data));
     if (!flash) {
         return secfalse;
     }