diff options
Diffstat (limited to 'kex.c')
| -rw-r--r-- | kex.c | 64 |
1 files changed, 63 insertions, 1 deletions
@@ -1,4 +1,4 @@ -/* $OpenBSD: kex.c,v 1.108 2015/07/29 08:34:54 djm Exp $ */ +/* $OpenBSD: kex.c,v 1.109 2015/07/30 00:01:34 djm Exp $ */ /* * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. * @@ -155,6 +155,68 @@ kex_names_valid(const char *names) return 1; } +/* + * Concatenate algorithm names, avoiding duplicates in the process. + * Caller must free returned string. + */ +char * +kex_names_cat(const char *a, const char *b) +{ + char *ret = NULL, *tmp = NULL, *cp, *p; + size_t len; + + if (a == NULL || *a == '\0') + return NULL; + if (b == NULL || *b == '\0') + return strdup(a); + if (strlen(b) > 1024*1024) + return NULL; + len = strlen(a) + strlen(b) + 2; + if ((tmp = cp = strdup(b)) == NULL || + (ret = calloc(1, len)) == NULL) { + free(tmp); + return NULL; + } + strlcpy(ret, a, len); + for ((p = strsep(&cp, ",")); p && *p != '\0'; (p = strsep(&cp, ","))) { + if (match_list(ret, p, NULL) != NULL) + continue; /* Algorithm already present */ + if (strlcat(ret, ",", len) >= len || + strlcat(ret, p, len) >= len) { + free(tmp); + free(ret); + return NULL; /* Shouldn't happen */ + } + } + free(tmp); + return ret; +} + +/* + * Assemble a list of algorithms from a default list and a string from a + * configuration file. The user-provided string may begin with '+' to + * indicate that it should be appended to the default. + */ +int +kex_assemble_names(const char *def, char **list) +{ + char *ret; + + if (list == NULL || *list == NULL || **list == '\0') { + *list = strdup(def); + return 0; + } + if (**list != '+') { + return 0; + } + + if ((ret = kex_names_cat(def, *list + 1)) == NULL) + return SSH_ERR_ALLOC_FAIL; + free(*list); + *list = ret; + return 0; +} + /* put algorithm proposal into buffer */ int kex_prop2buf(struct sshbuf *b, char *proposal[PROPOSAL_MAX]) |