Re: [sr-dev] git:master:74c84c7c: db_postgres: Fix heap use after free error in db_postgres module

Hello, following the discussion started by Chris Double, I am not sure this is the right fix. The column names are now allocated in pkg, but don't get freed, so looks like this commit introduced a memory leak. See: http://lists.sip-router.org/pipermail/sr-dev/2015-September/030565.html I think the commit has to be reverted and then remove db_postgres_free_query() at the end of db_postgres_store_result() Not using postgres module, but this seems the right from c coding point of view comparing with db_mysql. Cheers, Daniel On 28/08/15 12:11, Carsten Bock wrote: > Module: kamailio > Branch: master > Commit: 74c84c7cd52347fcd1c90e75dca239b5f758169b > URL: https://github.com/kamailio/kamailio/commit/74c84c7cd52347fcd1c90e75dca239b… > > Author: Carsten Bock <carsten(a)ng-voice.com> > Committer: Carsten Bock <carsten(a)ng-voice.com> > Date: 2015-08-28T12:11:25+02:00 > > db_postgres: Fix heap use after free error in db_postgres module > > The result structure for a query holds a pointer returned by > PQfname. When sql_do_query executes the query it gets this > database result structure returned but the PQfname pointer > has already been free'd by a call to db_postgres_free_query > from within db_postgres_store_result. > > sql_do_query then tries to copy the free'd string into another > result structure resulting in a heap use after free. > > The fix here copies the PQfname result. > > Fix by Chris Double > > --- > > Modified: modules/db_postgres/km_pg_con.c > Modified: modules/db_postgres/km_res.c > > --- > > Diff: https://github.com/kamailio/kamailio/commit/74c84c7cd52347fcd1c90e75dca239b… > Patch: https://github.com/kamailio/kamailio/commit/74c84c7cd52347fcd1c90e75dca239b… > > --- > > diff --git a/modules/db_postgres/km_pg_con.c b/modules/db_postgres/km_pg_con.c > index ec98add..d053c55 100644 > --- a/modules/db_postgres/km_pg_con.c > +++ b/modules/db_postgres/km_pg_con.c > @@ -71,10 +71,6 @@ struct pg_con* db_postgres_new_connection(struct db_id* id) > memset(ptr, 0, sizeof(struct pg_con)); > ptr->ref = 1; > > - memset(keywords, 0, (sizeof(char*) * 10)); > - memset(values, 0, (sizeof(char*) * 10)); > - memset(to, 0, (sizeof(char) * 16)); > - > if (id->port) { > ports = int2str(id->port, 0); > keywords[i] = "port"; > diff --git a/modules/db_postgres/km_res.c b/modules/db_postgres/km_res.c > index e9aa232..912206b 100644 > --- a/modules/db_postgres/km_res.c > +++ b/modules/db_postgres/km_res.c > @@ -126,8 +126,14 @@ int db_postgres_get_columns(const db1_con_t* _h, db1_res_t* _r) > RES_NAMES(_r)[col]); > > /* The pointer that is here returned is part of the result structure. */ > - RES_NAMES(_r)[col]->s = PQfname(CON_RESULT(_h), col); > - RES_NAMES(_r)[col]->len = strlen(PQfname(CON_RESULT(_h), col)); > + RES_NAMES(_r)[col]->s = pkg_malloc(strlen(PQfname(CON_RESULT(_h), col))+1); > + if (! RES_NAMES(_r)[col]->s) { > + LM_ERR("no private memory left\n"); > + db_free_columns(_r); > + return -4; > + } > + strcpy(RES_NAMES(_r)[col]->s, PQfname(CON_RESULT(_h), col)); > + RES_NAMES(_r)[col]->len = strlen(RES_NAMES(_r)[col]->s); > > LM_DBG("RES_NAMES(%p)[%d]=[%.*s]\n", RES_NAMES(_r)[col], col, > RES_NAMES(_r)[col]->len, RES_NAMES(_r)[col]->s); > > > _______________________________________________ > sr-dev mailing list > sr-dev(a)lists.sip-router.org > http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev