[PATCH v3 3/4] crypto: keytoc: Split env-provided full keyspec on spaces

[Jonas Rebmann <jre@pengutronix.de>]

keytoc/CONFIG_CRYPTO_PUBLIC_KEYS can work with a complete keyspec
provided by an environment variable as opposed to providing single URIs.
This would be a very useful feature if it could also provide any number
of keys. Kconfig however provides keytoc with regular keyspecs already
split at spaces so without furhter measures, the env variable can only
be expanded into a single key.

If a complete argument is provided via __ENV, split it at any space
character that is not escaped with a backslash in front of it.  An
actual backslash in a path needs to be escape with another backslash.

Signed-off-by: Jonas Rebmann <jre@pengutronix.de>
---
 scripts/keytoc.c | 55 ++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 42 insertions(+), 13 deletions(-)

diff --git a/scripts/keytoc.c b/scripts/keytoc.c
index 1b99393fdc..c451ee081a 100644
--- a/scripts/keytoc.c
+++ b/scripts/keytoc.c
@@ -10,6 +10,8 @@
 
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations" /* ENGINE deprecated in OpenSSL 3.0 */
 
+#include "include/string_util.h"
+
 #include <stdio.h>
 #include <string.h>
 #include <time.h>
@@ -787,6 +789,11 @@ static bool parse_info(char *p, struct keyinfo *out)
 
 static bool parse_keyspec(const char *keyspec, struct keyinfo *out)
 {
+	if (!strncmp(keyspec, "pkcs11:", 7)) { /* legacy format of pkcs11 URI */
+		out->path = strdup(keyspec);
+		return true;
+	}
+
 	char *sep, *spec;
 
 	spec = strdup(keyspec);
@@ -817,7 +824,7 @@ int main(int argc, char *argv[])
 {
 	int argi, opt, ret;
 	char *outfile = NULL;
-	int keycount;
+	size_t keycount, num_positionals;
 	struct keyinfo *keylist;
 
 	outfilep = stdout;
@@ -853,22 +860,44 @@ int main(int argc, char *argv[])
 		exit(1);
 	}
 
-	keycount = argc - optind;
-	keylist = calloc(sizeof(struct keyinfo), keycount);
 
-	for (argi = 0; argi < keycount; argi++) {
-		const char *keyspec = try_resolve_env(argv[optind + argi]);
-		struct keyinfo *info = &keylist[argi];
+	num_positionals = argc - optind;
+	keycount = num_positionals;
 
-		if (!keyspec)
-			exit(1);
+	keylist = calloc(keycount, sizeof(*keylist));
+
+	if (!keylist)
+		enomem_exit("push");
+
+	int listi = 0;
+
+	for (argi = 0; argi < num_positionals; argi++) {
+		char *arg = strdup(argv[optind + argi]);
+		char *resolved = try_resolve_env(arg);
 
-		if (!strncmp(keyspec, "pkcs11:", 7)) { // legacy format of pkcs11 URI
-			info->path = strdup(keyspec);
+		if (arg == resolved) {
+			keylist[listi].path = arg;
+			listi++;
 		} else {
-			if (!parse_keyspec(keyspec, info)) {
-				fprintf(stderr, "invalid keyspec %i: %s\n", optind, keyspec);
-				exit(1);
+			char *keyspecs = strdup(resolved);
+			char *keyspec;
+
+			/* Keyspec given as env Variable,
+			 * remove it and add an arbitrary number of keyspecs from its contents
+			 */
+			keycount--;
+			while ((keyspec = strsep_unescaped(&keyspecs, " ", NULL))) {
+				keycount++;
+				keylist = reallocarray(keylist, keycount, sizeof(*keylist));
+				if (!keylist)
+					enomem_exit("realloc keylist");
+				bzero(keylist + (keycount - 1), sizeof(*keylist));
+				if (!parse_keyspec(keyspec, &keylist[listi])) {
+					fprintf(stderr, "invalid keyspec %i: %s\n", optind,
+						keyspec);
+					exit(1);
+				}
+				listi++;
 			}
 		}
 	}

-- 
2.53.0.308.g50d063e335