Mercurial > hg > nginx
changeset 4619:3171ec7d0d05
Resolver: protection from duplicate responses.
If we already had CNAME in resolver node (i.e. rn->cnlen and rn->u.cname
set), and got additional response with A record, it resulted in rn->cnlen
set and rn->u.cname overwritten by rn->u.addr (or rn->u.addrs), causing
segmentation fault later in ngx_resolver_free_node() on an attempt to free
overwritten rn->u.cname. The opposite (i.e. CNAME got after A) might cause
similar problems as well.
| author | Maxim Dounin <mdounin@mdounin.ru> |
|---|---|
| date | Mon, 14 May 2012 09:13:45 +0000 |
| parents | c05cfc46b3bc |
| children | 204b780a89de |
| files | src/core/ngx_resolver.c |
| diffstat | 1 files changed, 10 insertions(+), 2 deletions(-) [+] |
line wrap: on
line diff
--- a/src/core/ngx_resolver.c +++ b/src/core/ngx_resolver.c @@ -513,8 +513,10 @@ ngx_resolve_name_locked(ngx_resolver_t * /* lock alloc mutex */ - ngx_resolver_free_locked(r, rn->query); - rn->query = NULL; + if (rn->query) { + ngx_resolver_free_locked(r, rn->query); + rn->query = NULL; + } if (rn->cnlen) { ngx_resolver_free_locked(r, rn->u.cname); @@ -1409,6 +1411,9 @@ ngx_resolver_process_a(ngx_resolver_t *r ngx_resolver_free(r, addrs); } + ngx_resolver_free(r, rn->query); + rn->query = NULL; + return; } else if (cname) { @@ -1441,6 +1446,9 @@ ngx_resolver_process_a(ngx_resolver_t *r (void) ngx_resolve_name_locked(r, ctx); } + ngx_resolver_free(r, rn->query); + rn->query = NULL; + return; }