Allow patches even when verification fails (#231)

Before patching the kernel image, it is possible that the kernel coincidentally contains KP1158\x00\x00, causing the checksum of the later data to fail.

This change loops through valid checksums and only determines a patched image if a valid checksum is found. If it is not found, it will be treated as a new image instead of just exiting.

Author: People-11

tools/patch.c

@@ -214,7 +214,33 @@ int parse_image_patch_info(const char *kimg, int kimg_len, patched_kimg_t *pimg)
     if (!pimg->banner) tools_loge_exit("can't find linux banner\n");
 
     // patched or new
-    preset_t *old_preset = get_preset(kimg, kimg_len);
+    preset_t *old_preset = NULL;
+    const char *search_ptr = kimg;
+    int search_len = kimg_len;
+    int32_t saved_kimg_len = 0;
+    int align_kimg_len = 0;
+
+    while (search_len > 0) {
+        old_preset = get_preset(search_ptr, search_len);
+        if (!old_preset) break;
+
+        saved_kimg_len = old_preset->setup.kimg_size;
+        if (is_be() ^ kinfo->is_be) saved_kimg_len = i32swp(saved_kimg_len);
+
+        align_kimg_len = (char *)old_preset - kimg;
+        if (align_kimg_len == (int)align_ceil(saved_kimg_len, SZ_4K)) {
+            break;
+        }
+
+        tools_logw("found magic string at 0x%x but saved kernel image size mismatch, ignoring (false positive?)\n",
+                   align_kimg_len);
+
+        // Search next
+        search_ptr = (char *)old_preset + 1;
+        search_len = kimg_len - (search_ptr - kimg);
+        old_preset = NULL;
+    }
+
     pimg->preset = old_preset;
 
     if (!old_preset) {
@@ -224,11 +250,6 @@ int parse_image_patch_info(const char *kimg, int kimg_len, patched_kimg_t *pimg)
     }
 
     tools_logi("patched kernel image ...\n");
-    int32_t saved_kimg_len = old_preset->setup.kimg_size;
-    if (is_be() ^ kinfo->is_be) saved_kimg_len = i32swp(saved_kimg_len);
-
-    int align_kimg_len = (char *)old_preset - kimg;
-    if (align_kimg_len != (int)align_ceil(saved_kimg_len, SZ_4K)) tools_loge_exit("saved kernel image size error\n");
     pimg->ori_kimg_len = saved_kimg_len;
 
     memcpy((char *)kimg, old_preset->setup.header_backup, sizeof(old_preset->setup.header_backup));