nfp: tls: don't leave key material in freed FW cmsg skbs
Make sure the contents of the skb which carried key material
to the FW is cleared.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/netronome/nfp/crypto/tls.c b/drivers/net/ethernet/netronome/nfp/crypto/tls.c
index d448c6d..96a96b3 100644
--- a/drivers/net/ethernet/netronome/nfp/crypto/tls.c
+++ b/drivers/net/ethernet/netronome/nfp/crypto/tls.c
@@ -4,6 +4,7 @@
#include <linux/bitfield.h>
#include <linux/ipv6.h>
#include <linux/skbuff.h>
+#include <linux/string.h>
#include <net/tls.h>
#include "../ccm.h"
@@ -340,8 +341,22 @@
memcpy(&back->salt, tls_ci->salt, TLS_CIPHER_AES_GCM_128_SALT_SIZE);
memcpy(back->rec_no, tls_ci->rec_seq, sizeof(tls_ci->rec_seq));
+ /* Get an extra ref on the skb so we can wipe the key after */
+ skb_get(skb);
+
err = nfp_ccm_mbox_communicate(nn, skb, NFP_CCM_TYPE_CRYPTO_ADD,
sizeof(*reply), sizeof(*reply));
+ reply = (void *)skb->data;
+
+ /* We depend on CCM MBOX code not reallocating skb we sent
+ * so we can clear the key material out of the memory.
+ */
+ if (!WARN_ON_ONCE((u8 *)back < skb->head ||
+ (u8 *)back > skb_end_pointer(skb)) &&
+ !WARN_ON_ONCE((u8 *)&reply[1] > (u8 *)back))
+ memzero_explicit(back, sizeof(*back));
+ dev_consume_skb_any(skb); /* the extra ref from skb_get() above */
+
if (err) {
nn_dp_warn(&nn->dp, "failed to add TLS: %d (%d)\n",
err, direction == TLS_OFFLOAD_CTX_DIR_TX);
@@ -349,7 +364,6 @@
goto err_conn_remove;
}
- reply = (void *)skb->data;
err = -be32_to_cpu(reply->error);
if (err) {
if (err == -ENOSPC) {
