commit 334b6a60abd9a44574efd16a5ef712a3721853e2
author Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no> Fri Jan 21 16:59:18 2022 +0100
committer Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no> Tue Oct 04 23:02:36 2022 +0200
tree 4325c2b5b54069c5c1faf62af3ceb0c13ac105b0
parent b22eb6a30d8328333039fa33405a00ab6494b0d4

boot: add precise check of the image size

It is possible that image in the slot is so big
that MCUboot swap metadata will interfere with
its content during the swap operation.

This patch introduces additional check to the image
validation procedure.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>

boot/bootutil/src/bootutil_misc.c

diff --git a/boot/bootutil/src/bootutil_misc.c b/boot/bootutil/src/bootutil_misc.c
index e2c70bc..94521c4 100644
--- a/boot/bootutil/src/bootutil_misc.c
+++ b/boot/bootutil/src/bootutil_misc.c
@@ -387,3 +387,27 @@
     return 0;
 }
 #endif
+
+uint32_t bootutil_max_image_size(const struct flash_area *fap)
+{
+#if defined(MCUBOOT_SWAP_USING_SCRATCH)
+    return boot_status_off(fap);
+#elif defined(MCUBOOT_SWAP_USING_MOVE)
+    struct flash_sector sector;
+    /* get the last sector offset */
+    int rc = flash_area_sector_from_off(boot_status_off(fap), &sector);
+    if (rc) {
+        BOOT_LOG_ERR("Unable to determine flash sector of the image trailer");
+        return 0; /* Returning of zero here should cause any check which uses
+                   * this value to fail.
+                   */
+    }
+    return flash_sector_get_off(&sector);
+#elif defined(MCUBOOT_OVERWRITE_ONLY)
+    return boot_swap_info_off(fap);
+#elif defined(MCUBOOT_DIRECT_XIP)
+    return boot_swap_info_off(fap);
+#elif defined(MCUBOOT_RAM_LOAD)
+    return boot_swap_info_off(fap);
+#endif
+}