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-rw-r--r--src/kex.c76
1 files changed, 75 insertions, 1 deletions
diff --git a/src/kex.c b/src/kex.c
index f34728c7..196f1b5e 100644
--- a/src/kex.c
+++ b/src/kex.c
@@ -281,6 +281,71 @@ char *ssh_find_matching(const char *available_d, const char *preferred_d){
return NULL;
}
+static char *ssh_find_all_matching(const char *available_d,
+ const char *preferred_d)
+{
+ char **tok_available, **tok_preferred;
+ int i_avail, i_pref;
+ char *ret;
+ unsigned max, len, pos = 0;
+
+ if ((available_d == NULL) || (preferred_d == NULL)) {
+ return NULL; /* don't deal with null args */
+ }
+
+ max = MAX(strlen(available_d), strlen(preferred_d));
+
+ ret = malloc(max+1);
+ if (ret == NULL) {
+ return NULL;
+ }
+ ret[0] = 0;
+
+ tok_available = tokenize(available_d);
+ if (tok_available == NULL) {
+ SAFE_FREE(ret);
+ return NULL;
+ }
+
+ tok_preferred = tokenize(preferred_d);
+ if (tok_preferred == NULL) {
+ SAFE_FREE(ret);
+ SAFE_FREE(tok_available[0]);
+ SAFE_FREE(tok_available);
+ return NULL;
+ }
+
+ for (i_pref = 0; tok_preferred[i_pref] ; ++i_pref) {
+ for (i_avail = 0; tok_available[i_avail]; ++i_avail) {
+ int cmp = strcmp(tok_available[i_avail],tok_preferred[i_pref]);
+ if (cmp == 0) {
+ /* match */
+ if (pos != 0) {
+ ret[pos] = ',';
+ pos++;
+ }
+
+ len = strlen(tok_available[i_avail]);
+ memcpy(&ret[pos], tok_available[i_avail], len);
+ pos += len;
+ ret[pos] = '\0';
+ }
+ }
+ }
+
+ if (ret[0] == '\0') {
+ SAFE_FREE(ret);
+ ret = NULL;
+ }
+
+ SAFE_FREE(tok_available[0]);
+ SAFE_FREE(tok_preferred[0]);
+ SAFE_FREE(tok_available);
+ SAFE_FREE(tok_preferred);
+
+ return ret;
+}
+
/**
* @internal
* @brief returns whether the first client key exchange algorithm or
@@ -668,4 +733,13 @@ int ssh_verify_existing_algo(int algo, const char *name){
return 0;
}
-/* vim: set ts=2 sw=2 et cindent: */
+/* returns a copy of the provided list if everything is supported,
+ * otherwise a new list of the supported algorithms */
+char *ssh_keep_known_algos(enum ssh_kex_types_e algo, const char *list)
+{
+ if (algo > SSH_LANG_S_C) {
+ return NULL;
+ }
+
+ return ssh_find_all_matching(supported_methods[algo], list);
+}