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 6F70B36309C; Mon, 4 May 2026 14:27:28 +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=1777904848; cv=none; b=BgFASraQtvBKb0nFqjk1SkfphHALXot1SNYle2dJRyoYf5x9cfFyzsvqdZ/7izDBnWC+AfjysV6h0oDJzcjJJ1QtbUDsv5ZNOPqbZDZSoVmAUu1KiRBfbv5xTH+VtPRDkSaRa1jAmRfOceZH50sSfiGrlu4m7unFfl/0+1kqvAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777904848; c=relaxed/simple; bh=K88QAZuwINKgHCAsU13WlJlt+FLOvvk/2iQo86uTxc8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ln9/as4n0U9jH0ub6R3sDv3bIIG3pEi7Icdm1YtYAnF1T7GK/JLBG5L7qyzWgviTly94zEDDtnOhuW6UhvKynbjXAc92oh+nDz4V7Oi87TrQvhA6XNTwyAKwGW8BtyPkqKqCESD8qZaSksv9Wv/v11OUflRaY21LFaHSALcajsk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vr14cb07; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="vr14cb07" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0B40C2BCB8; Mon, 4 May 2026 14:27:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777904848; bh=K88QAZuwINKgHCAsU13WlJlt+FLOvvk/2iQo86uTxc8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vr14cb07Tj5ZDkyaFFGW6Mm1Mv0GpiFH97CQQYRDH5I23cqelD6tyz14d2paL9q1V z6mu8rZPd7YbT2eczfAIEEuciufIMVGAmY4WQrqWfZlb8Mi0SYVXiHcaccCirhoGW8 zaKDsgGA/VXz4JF0gv+3Mq2L1WKwJiAOf1+0OPe0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Howells , Marc Dionne , Jeffrey Altman , Simon Horman , linux-afs@lists.infradead.org, stable@kernel.org, Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 197/215] rxrpc: Fix potential UAF after skb_unshare() failure Date: Mon, 4 May 2026 15:53:36 +0200 Message-ID: <20260504135137.710597208@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260504135130.169210693@linuxfoundation.org> References: <20260504135130.169210693@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ 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 [ adapted to per-skb rxrpc_input_call_event() signature ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/trace/events/rxrpc.h | 4 ++-- net/rxrpc/ar-internal.h | 1 - net/rxrpc/call_event.c | 24 ++++++++++++++++++++++-- net/rxrpc/io_thread.c | 24 ++---------------------- net/rxrpc/skbuff.c | 9 --------- 5 files changed, 26 insertions(+), 36 deletions(-) --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -127,8 +127,7 @@ 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_call_rx, "GET call-rx ") \ 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") \ @@ -153,6 +152,7 @@ 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 \ --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -1260,7 +1260,6 @@ int rxrpc_server_keyring(struct rxrpc_so 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 *); --- a/net/rxrpc/call_event.c +++ b/net/rxrpc/call_event.c @@ -342,8 +342,28 @@ bool rxrpc_input_call_event(struct rxrpc if (skb && skb->mark == RXRPC_SKB_MARK_ERROR) goto out; - 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 for + * 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); + } + } /* If we see our async-event poke, check for timeout trippage. */ now = ktime_get_real(); --- a/net/rxrpc/io_thread.c +++ b/net/rxrpc/io_thread.c @@ -178,13 +178,12 @@ static bool rxrpc_extract_abort(struct s /* * 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)); @@ -230,25 +229,6 @@ static bool rxrpc_input_packet(struct rx 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: @@ -490,7 +470,7 @@ 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); --- a/net/rxrpc/skbuff.c +++ b/net/rxrpc/skbuff.c @@ -47,15 +47,6 @@ void rxrpc_get_skb(struct sk_buff *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. */ void rxrpc_free_skb(struct sk_buff *skb, enum rxrpc_skb_trace why)