[iproute,v2] ipaddress: Fix segfault in 'addr showdump'

Message ID 20170913092034.7002-1-phil@nwl.cc
State Accepted
Delegated to: stephen hemminger
Headers show
Series
  • [iproute,v2] ipaddress: Fix segfault in 'addr showdump'
Related show

Commit Message

Phil Sutter Sept. 13, 2017, 9:20 a.m.
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.

Cc: Julien Fortin <julien@cumulusnetworks.com>
Fixes: d0e720111aad2 ("ip: ipaddress.c: add support for json output")
Signed-off-by: Phil Sutter <phil@nwl.cc>
--
Changes since v1:
Align json output with that of 'ip -j addr show':
- Interface index label is 'ifindex', not 'index' and it doesn't belong
  to 'addr_info' array.
- Create one 'addr_info' array per dumped address, not one for all.
---
 ip/ipaddress.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

Comments

Julien Fortin Sept. 15, 2017, 3:05 a.m. | #1
v2 looks good to me, thanks for catching this segfault.

On Wed, Sep 13, 2017 at 2:20 AM, Phil Sutter <phil@nwl.cc> 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.
>
> Cc: Julien Fortin <julien@cumulusnetworks.com>
> Fixes: d0e720111aad2 ("ip: ipaddress.c: add support for json output")
> Signed-off-by: Phil Sutter <phil@nwl.cc>

Acked-by: Julien Fortin <julien@cumulusnetworks.com>

> --
> Changes since v1:
> Align json output with that of 'ip -j addr show':
> - Interface index label is 'ifindex', not 'index' and it doesn't belong
>   to 'addr_info' array.
> - Create one 'addr_info' array per dumped address, not one for all.
> ---
>  ip/ipaddress.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/ip/ipaddress.c b/ip/ipaddress.c
> index 9797145023966..4c47809570410 100644
> --- a/ip/ipaddress.c
> +++ b/ip/ipaddress.c
> @@ -1801,17 +1801,33 @@ 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, "ifindex", "if%d:\n", ifa->ifa_index);
> +
> +       open_json_array(PRINT_JSON, "addr_info");
> +       open_json_object(NULL);
> +
>         print_addrinfo(NULL, n, stdout);
> +
> +       close_json_object();
> +       close_json_array(PRINT_JSON, NULL);
> +
> +       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);
> +       err = rtnl_from_file(stdin, &show_handler, NULL);
> +       delete_json_obj();
> +
> +       exit(err);
>  }
>
>  static int restore_handler(const struct sockaddr_nl *nl,
> --
> 2.13.1
>
Stephen Hemminger Sept. 21, 2017, 12:54 a.m. | #2
On Wed, 13 Sep 2017 11:20:34 +0200
Phil Sutter <phil@nwl.cc> 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.
> 
> Cc: Julien Fortin <julien@cumulusnetworks.com>
> Fixes: d0e720111aad2 ("ip: ipaddress.c: add support for json output")
> Signed-off-by: Phil Sutter <phil@nwl.cc>
> --
> Changes since v1:
> Align json output with that of 'ip -j addr show':
> - Interface index label is 'ifindex', not 'index' and it doesn't belong
>   to 'addr_info' array.
> - Create one 'addr_info' array per dumped address, not one for all.
> ---
>  ip/ipaddress.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
> 

Looks good, applied.

Patch

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 9797145023966..4c47809570410 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -1801,17 +1801,33 @@  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, "ifindex", "if%d:\n", ifa->ifa_index);
+
+	open_json_array(PRINT_JSON, "addr_info");
+	open_json_object(NULL);
+
 	print_addrinfo(NULL, n, stdout);
+
+	close_json_object();
+	close_json_array(PRINT_JSON, NULL);
+
+	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);
+	err = rtnl_from_file(stdin, &show_handler, NULL);
+	delete_json_obj();
+
+	exit(err);
 }
 
 static int restore_handler(const struct sockaddr_nl *nl,