Bug#821358: nss_hesiod segfaults in sock_eq

[Anders Kaseorg <andersk@mit.edu>]

notfound 821358 2.2.1-9
found 821358 2.22-0experimental0
tags 821358 + patch

I sent this patch upstream.  Since it only touches nss_hesiod, which is 
completely broken otherwise, it should be very low risk.

https://sourceware.org/ml/libc-alpha/2016-04/msg00563.html


2016-04-22  Anders Kaseorg  <andersk@mit.edu>

	[BZ #19573]
	* hesiod/hesiod.c (hesiod_end): Only call res_nclose(ctx->res) if
	ctx->free_res is nonnull, to prevent a crash on res_nclose(&res)
	introduced by commit 2212c1420c92a33b0e0bd9a34938c9814a56c0f7
	(Simplify handling of nameserver configuration in resolver).

diff --git a/hesiod/hesiod.c b/hesiod/hesiod.c
index 657dabe..a540382 100644
--- a/hesiod/hesiod.c
+++ b/hesiod/hesiod.c
@@ -152,12 +152,12 @@ hesiod_end(void *context) {
 	struct hesiod_p *ctx = (struct hesiod_p *) context;
 	int save_errno = errno;
 
-	if (ctx->res)
+	if (ctx->res && ctx->free_res) {
 		res_nclose(ctx->res);
+		(*ctx->free_res)(ctx->res);
+	}
 	free(ctx->RHS);
 	free(ctx->LHS);
-	if (ctx->res && ctx->free_res)
-		(*ctx->free_res)(ctx->res);
 	free(ctx);
 	__set_errno(save_errno);
 }


Anders