rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present

The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE
handler in rxrpc_verify_response() copy the skb to a linear one before
calling into the security ops only when skb_cloned() is true.  An skb
that is not cloned but still carries externally-owned paged fragments
(e.g. SKBFL_SHARED_FRAG set by splice() into a UDP socket via
__ip_append_data, or a chained skb_has_frag_list()) falls through to
the in-place decryption path, which binds the frag pages directly into
the AEAD/skcipher SGL via skb_to_sgvec().

Extend the gate to also unshare when skb_has_frag_list() or
skb_has_shared_frag() is true.  This catches the splice-loopback vector
and other externally-shared frag sources while preserving the
zero-copy fast path for skbs whose frags are kernel-private (e.g. NIC
page_pool RX, GRO).  The OOM/trace handling already in place is reused.

Fixes: d0d5c0cd1e71 ("rxrpc: Use skb_unshare() rather than skb_cow_data()")
Cc: stable@vger.kernel.org
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index fdd683261226cf9c087b1ed9e0f335b67b1d2eb9..2b19b252225e5560a537cedaa317436f6e6a9ac1 100644 (file)
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -334,7 +334,9 @@ bool rxrpc_input_call_event(struct rxrpc_call *call)
 
                        if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
                            sp->hdr.securityIndex != 0 &&
-                           skb_cloned(skb)) {
+                           (skb_cloned(skb) ||
+                            skb_has_frag_list(skb) ||
+                            skb_has_shared_frag(skb))) {
                                /* Unshare the packet so that it can be
                                 * modified by in-place decryption.
                                 */

diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index a2130d25aaa9b73a77f7d6ef28f2b2956189decc..442414d90ba1cd104b20025fdd1fb663fcc305d1 100644 (file)
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -245,7 +245,8 @@ static int rxrpc_verify_response(struct rxrpc_connection *conn,
 {
        int ret;
 
-       if (skb_cloned(skb)) {
+       if (skb_cloned(skb) || skb_has_frag_list(skb) ||
+           skb_has_shared_frag(skb)) {
                /* Copy the packet if shared so that we can do in-place
                 * decryption.
                 */