diff mbox series

[RFC,1/1] iw: add support for retrieving keys

Message ID 20220822074318.291949-2-raphael.melotte@mind.be
State New
Headers show
Series iw: add support for retrieving keys | expand

Commit Message

Raphaël Mélotte Aug. 22, 2022, 7:43 a.m. UTC 
For debugging purposes, it can be useful to be able to retrieve keys.

Add a "iw get key" command, to be able to retrieve keys when the key
index is known.

Example retrieving a pairwise key:
iw dev wlan0 get key 0 02:02:03:04:05:06

Example retrieving a group key:
iw dev wlan0 get key 1

Note that only the outer ATTR_KEY_DATA (and seq) is reported, the
nested KEY_DATA (and seq) within ATTR_KEY is not.

Signed-off-by: Raphaël Mélotte <raphael.melotte@mind.be>
---
 Makefile |  2 +-
 keys.c   | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 1 deletion(-)
 create mode 100644 keys.c

Comments

Johannes Berg Dec. 1, 2022, 1:37 p.m. UTC | #1 
On Mon, 2022-08-22 at 09:43 +0200, Raphaël Mélotte wrote:
> For debugging purposes, it can be useful to be able to retrieve keys.
> 
> Add a "iw get key" command, to be able to retrieve keys when the key
> index is known.
> 
> Example retrieving a pairwise key:
> iw dev wlan0 get key 0 02:02:03:04:05:06
> 
> Example retrieving a group key:
> iw dev wlan0 get key 1

The examples don't seem to match the docs:

> +COMMAND(get, key, "",
> +	NL80211_CMD_GET_KEY, 0, CIB_NETDEV, handle_get_key,
> +	"<key index> <MAC address> <pairwise>\n");

and maybe you should switch pairwise/mac addr since it's not required
for pairwise == false I guess? or maybe let you specify the key type
instead, so you can retrieve other kinds of keys?


> +	if (argc) {
> +		if (mac_addr_a2n(mac, argv[0]) == 0) {
> +			NLA_PUT(msg, NL80211_ATTR_MAC, 6, mac);
> +			argv++;
> +			argc--;
> +			nla_put_u32(msg, NL80211_ATTR_KEY_TYPE,
> NL80211_KEYTYPE_PAIRWISE);
> +		}

and this seems like it could have some error return in the else or
something?


Otherwise seems fine to me, any particular reason you sent it as RFC?

johannes
Raphaël Mélotte Jan. 2, 2023, 8:28 a.m. UTC | #2 
On 12/1/22 14:37, Johannes Berg wrote:
> The examples don't seem to match the docs:

Indeed.. I'll fix it.

> and maybe you should switch pairwise/mac addr since it's not required
> for pairwise == false I guess? or maybe let you specify the key type
> instead, so you can retrieve other kinds of keys?

I was actually thinking about removing the pairwise flag entirely.

Since the kernel currently only allows to retrieve pairwise or
group keys (AFAICT), I was thinking it could be easier to use the
presence of the MAC address to differentiate between the key
types.

> 
> and this seems like it could have some error return in the else or
> something?

Indeed, I'll add it.

> 
> Otherwise seems fine to me, any particular reason you sent it as RFC?

I thought there might have been a specific reason why it was not
there yet, and I also wasn't sure about 'NL80211_KEY_*' vs
'NL80211_ATTR_KEY_*'.

I'll send a v2 addressing the comments above.

Thanks for the review!

Raphaël
diff mbox series

Patch

diff --git a/Makefile b/Makefile
index 33aaf6a..aa4ce7e 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@  OBJS = iw.o genl.o event.o info.o phy.o \
 	mesh.o mpath.o mpp.o scan.o reg.o version.o \
 	reason.o status.o connect.o link.o offch.o ps.o cqm.o \
 	bitrate.o wowlan.o coalesce.o roc.o p2p.o vendor.o mgmt.o \
-	ap.o sha256.o nan.o bloom.o \
+	ap.o sha256.o nan.o bloom.o keys.o \
 	measurements.o ftm.o
 OBJS += sections.o
 
diff --git a/keys.c b/keys.c
new file mode 100644
index 0000000..3cb2950
--- /dev/null
+++ b/keys.c
@@ -0,0 +1,77 @@ 
+#include <errno.h>
+#include <netlink/genl/genl.h>
+#include <netlink/genl/family.h>
+#include <netlink/genl/ctrl.h>
+#include <netlink/msg.h>
+#include <netlink/attr.h>
+#include "nl80211.h"
+#include "iw.h"
+
+static int print_keys(struct nl_msg *msg, void *arg)
+{
+	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+	struct nlattr *tb[NL80211_ATTR_MAX + 1];
+
+	nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
+		  genlmsg_attrlen(gnlh, 0), NULL);
+
+	if (!tb[NL80211_ATTR_KEY_IDX]) {
+		fprintf(stderr, "KEY_IDX missing!\n");
+		return NL_SKIP;
+	}
+
+	if (!tb[NL80211_ATTR_KEY_DATA]) {
+		fprintf(stderr, "ATTR_KEY_DATA missing!\n");
+		return NL_SKIP;
+	}
+
+	iw_hexdump("Key", nla_data(tb[NL80211_ATTR_KEY_DATA]),
+		   nla_len(tb[NL80211_ATTR_KEY_DATA]));
+
+	if (!tb[NL80211_ATTR_KEY_SEQ]) {
+		fprintf(stderr, "ATTR_KEY_SEQ missing!\n");
+		return NL_SKIP;
+	}
+
+	iw_hexdump("Key seq", nla_data(tb[NL80211_ATTR_KEY_SEQ]),
+		   nla_len(tb[NL80211_ATTR_KEY_SEQ]));
+
+	return NL_OK;
+}
+
+static int handle_get_key(struct nl80211_state *state,
+			  struct nl_msg *msg, int argc, char **argv,
+			  enum id_input id)
+{
+	char *end;
+	unsigned char mac[6];
+
+	/* key index */
+	if (argc) {
+		nla_put_u8(msg, NL80211_ATTR_KEY_IDX, strtoul(argv[0], &end, 10));
+		argv++;
+		argc--;
+	}
+
+	/* mac */
+	if (argc) {
+		if (mac_addr_a2n(mac, argv[0]) == 0) {
+			NLA_PUT(msg, NL80211_ATTR_MAC, 6, mac);
+			argv++;
+			argc--;
+			nla_put_u32(msg, NL80211_ATTR_KEY_TYPE, NL80211_KEYTYPE_PAIRWISE);
+		}
+	} else {
+		nla_put_u32(msg, NL80211_ATTR_KEY_TYPE, NL80211_KEYTYPE_GROUP);
+	}
+
+	register_handler(print_keys, NULL);
+	return 0;
+
+ nla_put_failure:
+	return -ENOSPC;
+}
+
+COMMAND(get, key, "",
+	NL80211_CMD_GET_KEY, 0, CIB_NETDEV, handle_get_key,
+	"<key index> <MAC address> <pairwise>\n");