From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 304E01B4224 for ; Sun, 3 May 2026 14:06:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777817167; cv=none; b=SaaZXeVO9ooOk8V+WEnLWIZ6/NVxogCQV3lAss3zmHxr6dmanUydj/jRqEXUIl/jyR3jPXlvmIqNWThv3dYDAs7tHgeIsdUVK4i4tcC2rA6K4QCBZJDXlB1LKMTC2SC5h1vLw5xl00fojMNFaT9d49PaeRDtKNPuBRH6EIlN+rI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777817167; c=relaxed/simple; bh=BlYk7Vbw6PmdqTZcCbxDGoJzhru5HdyFtu7jnB0mAFo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HdPb1HMLq/OdFhC91iXbdRAmQyTFmZjoQ2CfT36ipgv/Tq68Ih69h6GjgF2YLjd/5oGfEzypnEyzlmX4S5Oy8w5BlKJp7oxsx/WrYVxQTmm8QnQtk2jgziTAKhG1fWscRaQM1mDPOTRPn3lwMlUDDtPF2mfHX0yhuxxAcXt/VUQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=j0GcBWbQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="j0GcBWbQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90134C2BCB4; Sun, 3 May 2026 14:06:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777817166; bh=BlYk7Vbw6PmdqTZcCbxDGoJzhru5HdyFtu7jnB0mAFo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j0GcBWbQSvGy+sLQogWtcD5t6A9CMGhb9pesrML+l2O3lEjGB2a9pL7WkBTKJapjL M9yrm19af54U8OjUNwD1ToifLJtS+FzUvovggzUdRDZVMjO32rBLqDyxx8UlZd5VGL aO3HIZu4kyS3qoTz7C0Jt4j9jMsvOdPRPQT3/7fS/BX0hlBJy7KsYHQHVOPRs9Zmu2 y7Twi21fYg9yWNx3ECNTaFKO9nk4jt/gJTTY0buRguuwToPYKeahwnHlZwGApT+l8q rNPAYxJ3849FB9GQuSqev7e9ufs7R3PyhcMjF4xlAO05kyYGMlRZq4a25kVAlooh5o pKNXst45Pf4sQ== From: Sasha Levin To: stable@vger.kernel.org Cc: David Howells , Marc Dionne , Jeffrey Altman , Simon Horman , linux-afs@lists.infradead.org, stable@kernel.org, Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6.y] rxrpc: Fix potential UAF after skb_unshare() failure Date: Sun, 3 May 2026 10:06:00 -0400 Message-ID: <20260503140600.1070829-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026050105-bless-arrogant-1e69@gregkh> References: <2026050105-bless-arrogant-1e69@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: David Howells [ Upstream commit 1f2740150f904bfa60e4bad74d65add3ccb5e7f8 ] If skb_unshare() fails to unshare a packet due to allocation failure in rxrpc_input_packet(), the skb pointer in the parent (rxrpc_io_thread()) will be NULL'd out. This will likely cause the call to trace_rxrpc_rx_done() to oops. Fix this by moving the unsharing down to where rxrpc_input_call_event() calls rxrpc_input_call_packet(). There are a number of places prior to that where we ignore DATA packets for a variety of reasons (such as the call already being complete) for which an unshare is then avoided. And with that, rxrpc_input_packet() doesn't need to take a pointer to the pointer to the packet, so change that to just a pointer. Fixes: 2d1faf7a0ca3 ("rxrpc: Simplify skbuff accounting in receive path") Closes: https://sashiko.dev/#/patchset/20260408121252.2249051-1-dhowells%40redhat.com Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/20260422161438.2593376-4-dhowells@redhat.com Signed-off-by: Jakub Kicinski [ Relocated the unshare/skb_copy block from rxrpc_input_call_event()'s rx_queue dequeue loop to existing `if (skb) rxrpc_input_call_packet()` site, and substituted rxrpc_skb_put_call_rx with rxrpc_skb_put_input. ] Signed-off-by: Sasha Levin --- include/trace/events/rxrpc.h | 3 +-- net/rxrpc/ar-internal.h | 1 - net/rxrpc/call_event.c | 23 +++++++++++++++++++++-- net/rxrpc/io_thread.c | 24 ++---------------------- net/rxrpc/skbuff.c | 9 --------- 5 files changed, 24 insertions(+), 36 deletions(-) diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index 6965099dda89f..94071243c4223 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -125,8 +125,6 @@ E_(rxrpc_call_poke_timer_now, "Timer-now") #define rxrpc_skb_traces \ - EM(rxrpc_skb_eaten_by_unshare, "ETN unshare ") \ - EM(rxrpc_skb_eaten_by_unshare_nomem, "ETN unshar-nm") \ EM(rxrpc_skb_get_conn_secured, "GET conn-secd") \ EM(rxrpc_skb_get_conn_work, "GET conn-work") \ EM(rxrpc_skb_get_last_nack, "GET last-nack") \ @@ -151,6 +149,7 @@ EM(rxrpc_skb_see_recvmsg, "SEE recvmsg ") \ EM(rxrpc_skb_see_reject, "SEE reject ") \ EM(rxrpc_skb_see_rotate, "SEE rotate ") \ + EM(rxrpc_skb_see_unshare_nomem, "SEE unshar-nm") \ E_(rxrpc_skb_see_version, "SEE version ") #define rxrpc_local_traces \ diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index f4512761f572d..1db479f3d6d3c 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -1269,7 +1269,6 @@ int rxrpc_server_keyring(struct rxrpc_sock *, sockptr_t, int); void rxrpc_kernel_data_consumed(struct rxrpc_call *, struct sk_buff *); void rxrpc_new_skb(struct sk_buff *, enum rxrpc_skb_trace); void rxrpc_see_skb(struct sk_buff *, enum rxrpc_skb_trace); -void rxrpc_eaten_skb(struct sk_buff *, enum rxrpc_skb_trace); void rxrpc_get_skb(struct sk_buff *, enum rxrpc_skb_trace); void rxrpc_free_skb(struct sk_buff *, enum rxrpc_skb_trace); void rxrpc_purge_queue(struct sk_buff_head *); diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c index 0f78544d043be..c8a4a4c979eb6 100644 --- a/net/rxrpc/call_event.c +++ b/net/rxrpc/call_event.c @@ -456,8 +456,27 @@ bool rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb) resend = true; } - if (skb) - rxrpc_input_call_packet(call, skb); + if (skb) { + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + + if (sp->hdr.securityIndex != 0 && skb_cloned(skb)) { + /* Unshare the packet so that it can be modified by + * in-place decryption. + */ + struct sk_buff *nskb = skb_copy(skb, GFP_ATOMIC); + + if (nskb) { + rxrpc_new_skb(nskb, rxrpc_skb_new_unshared); + rxrpc_input_call_packet(call, nskb); + rxrpc_free_skb(nskb, rxrpc_skb_put_input); + } else { + /* OOM - Drop the packet. */ + rxrpc_see_skb(skb, rxrpc_skb_see_unshare_nomem); + } + } else { + rxrpc_input_call_packet(call, skb); + } + } rxrpc_transmit_some_data(call); diff --git a/net/rxrpc/io_thread.c b/net/rxrpc/io_thread.c index 0491f2bbf61e0..f542eda13ff0b 100644 --- a/net/rxrpc/io_thread.c +++ b/net/rxrpc/io_thread.c @@ -167,13 +167,12 @@ static bool rxrpc_extract_abort(struct sk_buff *skb) /* * Process packets received on the local endpoint */ -static bool rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff **_skb) +static bool rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff *skb) { struct rxrpc_connection *conn; struct sockaddr_rxrpc peer_srx; struct rxrpc_skb_priv *sp; struct rxrpc_peer *peer = NULL; - struct sk_buff *skb = *_skb; bool ret = false; skb_pull(skb, sizeof(struct udphdr)); @@ -219,25 +218,6 @@ static bool rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff **_skb) return rxrpc_bad_message(skb, rxrpc_badmsg_zero_call); if (sp->hdr.seq == 0) return rxrpc_bad_message(skb, rxrpc_badmsg_zero_seq); - - /* Unshare the packet so that it can be modified for in-place - * decryption. - */ - if (sp->hdr.securityIndex != 0) { - skb = skb_unshare(skb, GFP_ATOMIC); - if (!skb) { - rxrpc_eaten_skb(*_skb, rxrpc_skb_eaten_by_unshare_nomem); - *_skb = NULL; - return just_discard; - } - - if (skb != *_skb) { - rxrpc_eaten_skb(*_skb, rxrpc_skb_eaten_by_unshare); - *_skb = skb; - rxrpc_new_skb(skb, rxrpc_skb_new_unshared); - sp = rxrpc_skb(skb); - } - } break; case RXRPC_PACKET_TYPE_CHALLENGE: @@ -479,7 +459,7 @@ int rxrpc_io_thread(void *data) switch (skb->mark) { case RXRPC_SKB_MARK_PACKET: skb->priority = 0; - if (!rxrpc_input_packet(local, &skb)) + if (!rxrpc_input_packet(local, skb)) rxrpc_reject_packet(local, skb); trace_rxrpc_rx_done(skb->mark, skb->priority); rxrpc_free_skb(skb, rxrpc_skb_put_input); diff --git a/net/rxrpc/skbuff.c b/net/rxrpc/skbuff.c index 3bcd6ee803960..e2169d1a14b5f 100644 --- a/net/rxrpc/skbuff.c +++ b/net/rxrpc/skbuff.c @@ -46,15 +46,6 @@ void rxrpc_get_skb(struct sk_buff *skb, enum rxrpc_skb_trace why) skb_get(skb); } -/* - * Note the dropping of a ref on a socket buffer by the core. - */ -void rxrpc_eaten_skb(struct sk_buff *skb, enum rxrpc_skb_trace why) -{ - int n = atomic_inc_return(&rxrpc_n_rx_skbs); - trace_rxrpc_skb(skb, 0, n, why); -} - /* * Note the destruction of a socket buffer. */ -- 2.53.0