[sr-dev] git:master:97db3ee6: db_mysql: safer conditions inside sb_add() for db api v2

[Daniel-Constantin Mierla]

Module: kamailio
Branch: master
Commit: 97db3ee61079de6cc2466628dae0f5e489819e98
URL: https://github.com/kamailio/kamailio/commit/97db3ee61079de6cc2466628dae0f5e489819e98

Author: Daniel-Constantin Mierla <miconda at gmail.com>
Committer: Daniel-Constantin Mierla <miconda at gmail.com>
Date: 2017-07-28T09:19:06+02:00

db_mysql: safer conditions inside sb_add() for db api v2

---

Modified: src/modules/db_mysql/my_cmd.c

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Diff:  https://github.com/kamailio/kamailio/commit/97db3ee61079de6cc2466628dae0f5e489819e98.diff
Patch: https://github.com/kamailio/kamailio/commit/97db3ee61079de6cc2466628dae0f5e489819e98.patch

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diff --git a/src/modules/db_mysql/my_cmd.c b/src/modules/db_mysql/my_cmd.c
index 7872568b29..8502e6d323 100644
--- a/src/modules/db_mysql/my_cmd.c
+++ b/src/modules/db_mysql/my_cmd.c
@@ -372,8 +372,10 @@ static inline int sb_add(struct string_buffer *sb, str *nstr)
 	int rsize = sb->len + nstr->len;
 	int asize;
 	char *newp;
-	
-	if ( rsize > sb->size ) {
+
+	if(nstr->len==0) return 0;
+
+	if ( sb->s==NULL || rsize > sb->size ) {
 		asize = rsize - sb->size;
 		new_size = sb->size + (asize / sb->increment  + (asize % sb->increment > 0)) * sb->increment;
 		newp = pkg_malloc(new_size);
@@ -423,6 +425,9 @@ static int build_update_cmd(str* sql_cmd, db_cmd_t* cmd)
 	rv = sb_add(&sql_buf, &strings[STR_UPDATE]);	/* "UPDATE " */
 	rv |= sb_add(&sql_buf, &cmd->table);			/* table name */
 	rv |= sb_add(&sql_buf, &strings[STR_SET]);		/* " SET " */
+	if (rv) {
+		goto err;
+	}
 
 	/* column name-value pairs */
 	for(i = 0, fld = cmd->vals; !DB_FLD_LAST(fld[i]); i++) {