From e0b7ff46c98ef19afe58b21df9255d243de1a662 Mon Sep 17 00:00:00 2001
From: LOLi <loli10K@users.noreply.github.com>
Date: Tue, 18 Sep 2018 18:43:09 +0200
Subject: [PATCH] zstreamdump dumps core printing truncated nvlist

This change prevents zstreamdump from crashing when trying to print
invalid nvlist data (DRR_BEGIN record) from a truncated send stream.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes #7917
---
 cmd/zstreamdump/zstreamdump.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/cmd/zstreamdump/zstreamdump.c b/cmd/zstreamdump/zstreamdump.c
index 6c7150b10..a2edefa92 100644
--- a/cmd/zstreamdump/zstreamdump.c
+++ b/cmd/zstreamdump/zstreamdump.c
@@ -384,10 +384,12 @@ main(int argc, char *argv[])
 				if (ferror(send_stream))
 					perror("fread");
 				err = nvlist_unpack(buf, sz, &nv, 0);
-				if (err)
+				if (err) {
 					perror(strerror(err));
-				nvlist_print(stdout, nv);
-				nvlist_free(nv);
+				} else {
+					nvlist_print(stdout, nv);
+					nvlist_free(nv);
+				}
 			}
 			break;