rtp_engine: Prevent possible double free with DTLS config

ASTERISK-27225 #close
Reported by: Richard Kenner

Change-Id: I097b81734ef730f8603c0b972909d212a3a5cf89

diff --git a/main/rtp_engine.c b/main/rtp_engine.c
index 8d6c337a48b252b6d5f489d09a0aa87b580e7d86..2f91b5a6468bb0d71d8856982b77ed09aa195c03 100644 (file)
--- a/main/rtp_engine.c
+++ b/main/rtp_engine.c
@@ -2702,35 +2702,35 @@ int ast_rtp_dtls_cfg_parse(struct ast_rtp_dtls_cfg *dtls_cfg, const char *name,
                        return -1;
                }
        } else if (!strcasecmp(name, "dtlscertfile")) {
-               ast_free(dtls_cfg->certfile);
                if (!ast_strlen_zero(value) && !ast_file_is_readable(value)) {
                        ast_log(LOG_ERROR, "%s file %s does not exist or is not readable\n", name, value);
                        return -1;
                }
+               ast_free(dtls_cfg->certfile);
                dtls_cfg->certfile = ast_strdup(value);
        } else if (!strcasecmp(name, "dtlsprivatekey")) {
-               ast_free(dtls_cfg->pvtfile);
                if (!ast_strlen_zero(value) && !ast_file_is_readable(value)) {
                        ast_log(LOG_ERROR, "%s file %s does not exist or is not readable\n", name, value);
                        return -1;
                }
+               ast_free(dtls_cfg->pvtfile);
                dtls_cfg->pvtfile = ast_strdup(value);
        } else if (!strcasecmp(name, "dtlscipher")) {
                ast_free(dtls_cfg->cipher);
                dtls_cfg->cipher = ast_strdup(value);
        } else if (!strcasecmp(name, "dtlscafile")) {
-               ast_free(dtls_cfg->cafile);
                if (!ast_strlen_zero(value) && !ast_file_is_readable(value)) {
                        ast_log(LOG_ERROR, "%s file %s does not exist or is not readable\n", name, value);
                        return -1;
                }
+               ast_free(dtls_cfg->cafile);
                dtls_cfg->cafile = ast_strdup(value);
        } else if (!strcasecmp(name, "dtlscapath") || !strcasecmp(name, "dtlscadir")) {
-               ast_free(dtls_cfg->capath);
                if (!ast_strlen_zero(value) && !ast_file_is_readable(value)) {
                        ast_log(LOG_ERROR, "%s file %s does not exist or is not readable\n", name, value);
                        return -1;
                }
+               ast_free(dtls_cfg->capath);
                dtls_cfg->capath = ast_strdup(value);
        } else if (!strcasecmp(name, "dtlssetup")) {
                if (!strcasecmp(value, "active")) {