[PATCH] nfc: fix potential NULL pointer deref in nfc_genl_dump_ses_done

The done() netlink callback nfc_genl_dump_ses_done() should check if
received argument is non-NULL, because its allocation could fail earlier
in dumpit() (nfc_genl_dump_ses()).

Fixes: ac22ac466a65 ("NFC: Add a GET_SE netlink API")
Cc: <redacted>
Signed-off-by: Krzysztof Kozlowski <redacted>
---
 net/nfc/netlink.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index 334f63c9529e..5c706ed75b33 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c

@@ -1392,8 +1392,10 @@ static int nfc_genl_dump_ses_done(struct netlink_callback *cb)
 {
 	struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
 
-	nfc_device_iter_exit(iter);
-	kfree(iter);
+	if (iter) {
+		nfc_device_iter_exit(iter);
+		kfree(iter);
+	}
 
 	return 0;
 }

-- 
2.32.0

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski [off-list ref]:

On Thu,  9 Dec 2021 09:13:07 +0100 you wrote:

The done() netlink callback nfc_genl_dump_ses_done() should check if
received argument is non-NULL, because its allocation could fail earlier
in dumpit() (nfc_genl_dump_ses()).

Fixes: ac22ac466a65 ("NFC: Add a GET_SE netlink API")
Cc: <redacted>
Signed-off-by: Krzysztof Kozlowski <redacted>

[...]

Here is the summary with links:
  - nfc: fix potential NULL pointer deref in nfc_genl_dump_ses_done
    https://git.kernel.org/netdev/net/c/fd79a0cbf0b2

You are awesome, thank you!
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