[iproute PATCH] ipaddress: Fix segfault in 'addr showdump'

[iproute PATCH] ipaddress: Fix segfault in 'addr showdump'

[Phil Sutter]

Obviously, 'addr showdump' feature wasn't adjusted to json output
support. As a consequence, calls to print_string() in print_addrinfo()
tried to dereference a NULL FILE pointer.

Fixes: d0e720111aad2 ("ip: ipaddress.c: add support for json output")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 ip/ipaddress.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 9797145023966..ee6c9f588e7ba 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -1801,17 +1801,31 @@ static int show_handler(const struct sockaddr_nl *nl,
 {
 	struct ifaddrmsg *ifa = NLMSG_DATA(n);
 
-	printf("if%d:\n", ifa->ifa_index);
+	open_json_object(NULL);
+	print_int(PRINT_ANY, "index", "if%d:\n", ifa->ifa_index);
 	print_addrinfo(NULL, n, stdout);
+	close_json_object();
 	return 0;
 }
 
 static int ipaddr_showdump(void)
 {
+	int err;
+
 	if (ipadd_dump_check_magic())
 		exit(-1);
 
-	exit(rtnl_from_file(stdin, &show_handler, NULL));
+	new_json_obj(json, stdout);
+	open_json_object(NULL);
+	open_json_array(PRINT_JSON, "addr_info");
+
+	err = rtnl_from_file(stdin, &show_handler, NULL);
+
+	close_json_array(PRINT_JSON, NULL);
+	close_json_object();
+	delete_json_obj();
+
+	exit(err);
 }
 
 static int restore_handler(const struct sockaddr_nl *nl,
-- 
2.13.1

Re: [iproute PATCH] ipaddress: Fix segfault in 'addr showdump'

[Phil Sutter]

On Tue, Sep 12, 2017 at 04:58:12PM +0200, Phil Sutter wrote:
> Obviously, 'addr showdump' feature wasn't adjusted to json output
> support. As a consequence, calls to print_string() in print_addrinfo()
> tried to dereference a NULL FILE pointer.

Please ignore this patch - it generates incorrect json output. I'll send
a v2 which fixes that.

Thanks, Phil