cmd: source: Support specifying config name

As discussed previously [1,2], the source command is not safe to use with
verified boot unless there is a key with required = "images" (which has its
own problems). This is because if such a key is absent, signatures are
verified but not required. It is assumed that configuration nodes will
provide the signature. Because the source command does not use
configurations to determine the image to source, effectively no
verification takes place.

To address this, allow specifying configuration nodes. We use the same
syntax as the bootm command (helpfully provided for us by fit_parse_conf).
By default, we first try the default config and then the default image. To
force using a config, # must be present in the command (e.g. `source
$loadaddr#my-conf`). For convenience, the config may be omitted, just like
the address may be (e.g. `source \#`). This also works for images
(`source :` behaves exactly like `source` currently does).

[1] https://lore.kernel.org/u-boot/7d711133-d513-5bcb-52f2-a9dbaa9eeded@prevas.dk/
[2] https://lore.kernel.org/u-boot/042dcb34-f85f-351e-1b0e-513f89005fdd@gmail.com/

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/mach-stm32mp/cmd_stm32prog/cmd_stm32prog.c

@@ -154,7 +154,7 @@ static int do_stm32prog(struct cmd_tbl *cmdtp, int flag, int argc,
 			do_bootz(cmdtp, 0, 4, bootm_argv);
 	}
 	if (data->script)
-		image_source_script(data->script, NULL);
+		image_source_script(data->script, NULL, NULL);
 
 	if (reset) {
 		puts("Reset...\n");

boot/bootmeth_script.c

@@ -101,7 +101,7 @@ static int script_boot(struct udevice *dev, struct bootflow *bflow)
 	log_debug("mmc_bootdev: %s\n", env_get("mmc_bootdev"));
 
 	addr = map_to_sysmem(bflow->buf);
-	ret = image_source_script(addr, NULL);
+	ret = image_source_script(addr, NULL, NULL);
 	if (ret)
 		return log_msg_ret("boot", ret);
 

cmd/source.c

@@ -42,7 +42,7 @@ static const char *get_default_image(const void *fit)
 }
 #endif
 
-int image_source_script(ulong addr, const char *fit_uname)
+int image_source_script(ulong addr, const char *fit_uname, const char *confname)
 {
 	ulong		len;
 #if defined(CONFIG_LEGACY_IMAGE_FORMAT)
@@ -112,19 +112,47 @@ int image_source_script(ulong addr, const char *fit_uname)
 			return 1;
 		}
 
-		if (!fit_uname)
-			fit_uname = get_default_image(fit_hdr);
-
 		if (!fit_uname) {
-			puts("No FIT subimage unit name\n");
-			return 1;
-		}
+			/* If confname is empty, use the default */
+			if (confname && *confname)
+				noffset = fit_conf_get_node(fit_hdr, confname);
+			else
+				noffset = fit_conf_get_node(fit_hdr, NULL);
+			if (noffset < 0) {
+				if (!confname)
+					goto fallback;
+				printf("Could not find config %s\n", confname);
+				return 1;
+			}
 
-		/* get script component image node offset */
-		noffset = fit_image_get_node (fit_hdr, fit_uname);
-		if (noffset < 0) {
-			printf ("Can't find '%s' FIT subimage\n", fit_uname);
-			return 1;
+			if (verify && fit_config_verify(fit_hdr, noffset))
+				return 1;
+
+			noffset = fit_conf_get_prop_node(fit_hdr, noffset,
+							 FIT_SCRIPT_PROP,
+							 IH_PHASE_NONE);
+			if (noffset < 0) {
+				if (!confname)
+					goto fallback;
+				printf("Could not find script in %s\n", confname);
+				return 1;
+			}
+		} else {
+fallback:
+			if (!fit_uname || !*fit_uname)
+				fit_uname = get_default_image(fit_hdr);
+			if (!fit_uname) {
+				puts("No FIT subimage unit name\n");
+				return 1;
+			}
+
+			/* get script component image node offset */
+			noffset = fit_image_get_node(fit_hdr, fit_uname);
+			if (noffset < 0) {
+				printf("Can't find '%s' FIT subimage\n",
+				       fit_uname);
+				return 1;
+			}
 		}
 
 		if (!fit_image_check_type (fit_hdr, noffset, IH_TYPE_SCRIPT)) {
@@ -164,7 +192,7 @@ static int do_source(struct cmd_tbl *cmdtp, int flag, int argc,
 {
 	ulong addr;
 	int rcode;
-	const char *fit_uname = NULL;
+	const char *fit_uname = NULL, *confname = NULL;
 
 	/* Find script image */
 	if (argc < 2) {
@@ -175,6 +203,9 @@ static int do_source(struct cmd_tbl *cmdtp, int flag, int argc,
 				      &fit_uname)) {
 		debug("*  source: subimage '%s' from FIT image at 0x%08lx\n",
 		      fit_uname, addr);
+	} else if (fit_parse_conf(argv[1], image_load_addr, &addr, &confname)) {
+		debug("*  source: config '%s' from FIT image at 0x%08lx\n",
+		      confname, addr);
 #endif
 	} else {
 		addr = hextoul(argv[1], NULL);
@@ -182,21 +213,22 @@ static int do_source(struct cmd_tbl *cmdtp, int flag, int argc,
 	}
 
 	printf ("## Executing script at %08lx\n", addr);
-	rcode = image_source_script(addr, fit_uname);
+	rcode = image_source_script(addr, fit_uname, confname);
 	return rcode;
 }
 
 #ifdef CONFIG_SYS_LONGHELP
 static char source_help_text[] =
-	"[addr]\n"
-	"\t- run script starting at addr\n"
-	"\t- A valid image header must be present"
 #if defined(CONFIG_FIT)
-	"\n"
-	"For FIT format uImage addr must include subimage\n"
-	"unit name in the form of addr:<subimg_uname>"
+	"[<addr>][:[<image>]|#[<config>]]\n"
+	"\t- Run script starting at addr\n"
+	"\t- A FIT config name or subimage name may be specified with : or #\n"
+	"\t  (like bootm). If the image or config name is omitted, the\n"
+	"\t  default is used.";
+#else
+	"[<addr>]\n"
+	"\t- Run script starting at addr";
 #endif
-	"";
 #endif
 
 U_BOOT_CMD(

doc/uImage.FIT/source_file_format.txt

@@ -247,6 +247,7 @@ o config-1
   |- kernel = "kernel sub-node unit name"
   |- fdt = "fdt sub-node unit-name" [, "fdt overlay sub-node unit-name", ...]
   |- loadables = "loadables sub-node unit-name"
+  |- script = "
   |- compatible = "vendor,board-style device tree compatible string"
 
 
@@ -268,6 +269,8 @@ o config-1
     of strings. U-Boot will load each binary at its given start-address and
     may optionally invoke additional post-processing steps on this binary based
     on its component image node type.
+  - script : The image to use when loading a U-Boot script (for use with the
+    source command).
   - compatible : The root compatible string of the U-Boot device tree that
     this configuration shall automatically match when CONFIG_FIT_BEST_MATCH is
     enabled. If this property is not provided, the compatible string will be

drivers/usb/gadget/f_sdp.c

@@ -868,7 +868,7 @@ static int sdp_handle_in_ep(struct spl_image_info *spl_image,
 			jump_to_image_no_args(&spl_image);
 #else
 			/* In U-Boot, allow jumps to scripts */
-			image_source_script(sdp_func->jmp_address, NULL);
+			image_source_script(sdp_func->jmp_address, NULL, NULL);
 #endif
 		}
 

include/image.h

@@ -711,15 +711,23 @@ int fit_image_load(struct bootm_headers *images, ulong addr,
 
 /**
  * image_source_script() - Execute a script
+ * @addr: Address of script
+ * @fit_uname: FIT subimage name
+ * @confname: FIT config name. The subimage is chosen based on FIT_SCRIPT_PROP.
  *
  * Executes a U-Boot script at a particular address in memory. The script should
  * have a header (FIT or legacy) with the script type (IH_TYPE_SCRIPT).
  *
- * @addr: Address of script
- * @fit_uname: FIT subimage name
+ * If @fit_uname is the empty string, then the default image is used. If
+ * @confname is the empty string, the default config is used. If @confname and
+ * @fit_uname are both non-%NULL, then @confname is ignored. If @confname and
+ * @fit_uname are both %NULL, then first the default config is tried, and then
+ * the default image.
+ *
  * Return: result code (enum command_ret_t)
  */
-int image_source_script(ulong addr, const char *fit_uname);
+int image_source_script(ulong addr, const char *fit_uname,
+			const char *confname);
 
 /**
  * fit_get_node_from_config() - Look up an image a FIT by type
@@ -1032,6 +1040,7 @@ int booti_setup(ulong image, ulong *relocated_addr, ulong *size,
 #define FIT_FPGA_PROP		"fpga"
 #define FIT_FIRMWARE_PROP	"firmware"
 #define FIT_STANDALONE_PROP	"standalone"
+#define FIT_SCRIPT_PROP		"script"
 #define FIT_PHASE_PROP		"phase"
 
 #define FIT_MAX_HASH_LEN	HASH_MAX_DIGEST_SIZE

test/py/tests/test_source.py

@@ -18,11 +18,20 @@ def test_source(u_boot_console):
     util.run_and_log(cons, (mkimage, '-f', its, fit))
     cons.run_command(f'host load hostfs - $loadaddr {fit}')
 
-    assert '1' in cons.run_command('source')
+    assert '2' in cons.run_command('source')
+    assert '1' in cons.run_command('source :')
     assert '1' in cons.run_command('source :script-1')
     assert '2' in cons.run_command('source :script-2')
     assert 'Fail' in cons.run_command('source :not-a-script || echo Fail')
+    assert '2' in cons.run_command('source \\#')
+    assert '1' in cons.run_command('source \\#conf-1')
+    assert '2' in cons.run_command('source \\#conf-2')
 
     cons.run_command('fdt addr $loadaddr')
+    cons.run_command('fdt rm /configurations default')
+    assert '1' in cons.run_command('source')
+    assert 'Fail' in cons.run_command('source \\# || echo Fail')
+
     cons.run_command('fdt rm /images default')
     assert 'Fail' in cons.run_command('source || echo Fail')
+    assert 'Fail' in cons.run_command('source \\# || echo Fail')