veritysetup: fix parsing of root-hash-signature= option

The function was named confusingly and we managed to confused ourselves. The
parameter was assigned incorrectly and then reassigned correctly in the caller.
Let's simplify the whole thing by just saving the optarg param.

I considered moving the unhexmemming and/or reading of the file to the parse
function, but decided against it. I think it's nicer to parse all options
before opening external files.

1 files changed, 17 insertions, 34 deletions

diff --git a/src/veritysetup/veritysetup.c b/src/veritysetup/veritysetup.c
index 1536bb2b88..3b5cb53b4a 100644
--- a/src/veritysetup/veritysetup.c
+++ b/src/veritysetup/veritysetup.c
@@ -16,9 +16,7 @@
 #include "terminal-util.h"
 
 static uint32_t arg_activate_flags = CRYPT_ACTIVATE_READONLY;
-static char *arg_root_hash_signature = NULL;
-
-STATIC_DESTRUCTOR_REGISTER(arg_root_hash_signature, freep);
+static const char *arg_root_hash_signature = NULL;
 
 static int help(void) {
         _cleanup_free_ char *link = NULL;
@@ -39,37 +37,29 @@ static int help(void) {
         return 0;
 }
 
-static int looks_like_roothashsig(const char *option) {
-        const char *val;
-        int r;
-
-        if (path_is_absolute(option)) {
-
-                r = free_and_strdup(&arg_root_hash_signature, option);
-                if (r < 0)
-                        return log_oom();
-
-                return 1;
-        }
-
-        val = startswith(option, "base64:");
-        if (val) {
+static int save_roothashsig_option(const char *option, bool strict) {
 
-                r = free_and_strdup(&arg_root_hash_signature, val);
-                if (r < 0)
-                        return log_oom();
+        if (path_is_absolute(option) || startswith(option, "base64:")) {
+                if (!HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY)
+                        return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                               "Activation of verity device with signature requested, but cryptsetup does not support crypt_activate_by_signed_key().");
 
-                return 1;
+                arg_root_hash_signature = option;
+                return true;
         }
 
-        return 0;
+        if (!strict)
+                return false;
+        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                               "root-hash-signature= expects either full path to signature file or "
+                               "base64 string encoding signature prefixed by base64:.");
 }
 
 static int parse_options(const char *options) {
         int r;
 
         /* backward compatibility with the obsolete ROOTHASHSIG positional argument */
-        r = looks_like_roothashsig(options);
+        r = save_roothashsig_option(options, false);
         if (r < 0)
                 return r;
         if (r == 1) {
@@ -108,17 +98,10 @@ static int parse_options(const char *options) {
                         arg_activate_flags |= CRYPT_ACTIVATE_PANIC_ON_CORRUPTION;
 #endif
                 else if ((val = startswith(word, "root-hash-signature="))) {
-
-                        r = looks_like_roothashsig(val);
+                        r = save_roothashsig_option(val, true);
                         if (r < 0)
                                 return r;
-                        if (r == 0)
-                                return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "root-hash-signature expects either full path to signature file or "
-                                                                                "base64 string encoding signature prefixed by base64:.");
 
-                        r = free_and_strdup(&arg_root_hash_signature, val);
-                        if (r < 0)
-                                return log_oom();
                 } else
                         log_warning("Encountered unknown option '%s', ignoring.", word);
         }
@@ -183,7 +166,7 @@ static int run(int argc, char *argv[]) {
                 if (r < 0)
                         return log_error_errno(r, "Failed to configure data device: %m");
 
-                if (arg_root_hash_signature && *arg_root_hash_signature) {
+                if (arg_root_hash_signature) {
 #if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY
                         _cleanup_free_ char *hash_sig = NULL;
                         size_t hash_sig_size;
@@ -205,7 +188,7 @@ static int run(int argc, char *argv[]) {
 
                         r = crypt_activate_by_signed_key(cd, argv[2], m, l, hash_sig, hash_sig_size, arg_activate_flags);
 #else
-                        return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "activation of verity device with signature %s requested, but not supported by cryptsetup due to missing crypt_activate_by_signed_key()", argv[6]);
+                        assert_not_reached();
 #endif
                 } else
                         r = crypt_activate_by_volume_key(cd, argv[2], m, l, arg_activate_flags);