res_pjsip_pubsub.c: Fix one byte buffer overrun error.

ast_sip_pubsub_register_body_generator() did not account for the null
terminator set by sprintf() in the allocated output buffer.

Change-Id: I388688a132e479bca6ad1c19275eae0070969ae2

diff --git a/res/res_pjsip_pubsub.c b/res/res_pjsip_pubsub.c
index f8187897a0bfd1626beec257f3f9b06761593d92..c60151e3c355236ef2017ea4adde00d33115fb2e 100644 (file)
--- a/res/res_pjsip_pubsub.c
+++ b/res/res_pjsip_pubsub.c
@@ -2995,16 +2995,13 @@ int ast_sip_pubsub_register_body_generator(struct ast_sip_pubsub_body_generator
        AST_LIST_INSERT_HEAD(&body_generators, generator, list);
        AST_RWLIST_UNLOCK(&body_generators);
 
-       /* Lengths of type and subtype plus space for a slash. pj_str_t is not
-        * null-terminated, so there is no need to allocate for the extra null
-        * byte
-        */
+       /* Lengths of type and subtype plus a slash. */
        accept_len = strlen(generator->type) + strlen(generator->subtype) + 1;
 
-       accept.ptr = ast_alloca(accept_len);
-       accept.slen = accept_len;
-       /* Safe use of sprintf */
-       sprintf(accept.ptr, "%s/%s", generator->type, generator->subtype);
+       /* Add room for null terminator that sprintf() will set. */
+       pj_strset(&accept, ast_alloca(accept_len + 1), accept_len);
+       sprintf((char *) pj_strbuf(&accept), "%s/%s", generator->type, generator->subtype);/* Safe */
+
        pjsip_endpt_add_capability(ast_sip_get_pjsip_endpoint(), &pubsub_module,
                        PJSIP_H_ACCEPT, NULL, 1, &accept);