From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4A482451056; Tue, 16 Jun 2026 16:08:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781626113; cv=none; b=IgDRQf517XfRqkq5taCB8+e/LJULD684OhBRM2SfWIPiJ2e4ai7Rj4w7RezdNvfWjCv8HkhfdgmTaFFumoOZ87OOsrKnUA12FKzQSRU3zzsgMq12W5rz7+Z03H1nHEZbZPZe5zuSueVL0XWEZciXX2NONBDWo2ant8wlsAhq6XA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781626113; c=relaxed/simple; bh=PSxsqmTZBvEdRi31CbteAUnBuzedeTOvd1tuZd1tA4A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hb7zNEAZXlhdcr9sS8svTBBLdzcBmqTnQSvI0tGBJM1WeBhNi75gKGKUtlsrBaLVivskwlXYnVLN98hKBsk9IXsBfvlUrXvyY05WjgRwzZEZ62dnlk4oP3NIs9HyscgU2I8sof7wwDoPah/4HpoUwruwiSf3c7FLadJRSaKBGac= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TtWukzA2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TtWukzA2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41E3F1F000E9; Tue, 16 Jun 2026 16:08:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781626112; bh=MeNTaO4byxvabOY6OxHZs0mR0TZrCeNwGa0VEULHMfg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TtWukzA2H5qY7YmhuKwc9cjw7xTBVV4ZRmArM7PXtCt/QKyhcTUdEst5aau7HsYrp wY+5gJcPQafGF956yE4UsPKFZY9lmq/+xYq1RXj31qhvpm6QSCNix2oPDt8s4mS88N 6sjrp86jLtKn6OGUC83uCf3vRhC5cfWQhnRUvqdg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Bommarito , David Howells , Marc Dionne , Jeffrey Altman , Eric Dumazet , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Simon Horman , linux-afs@lists.infradead.org, netdev@vger.kernel.org, stable@kernel.org Subject: [PATCH 6.18 266/325] rxrpc: Fix the ACK parser to extract the SACK table for parsing Date: Tue, 16 Jun 2026 20:31:02 +0530 Message-ID: <20260616145111.888384892@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145057.827196531@linuxfoundation.org> References: <20260616145057.827196531@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells commit 333b6d5bb9f87827ac2639c737bf9613dbae7253 upstream. Fix modification of the received skbuff in rxrpc_input_soft_acks() and a potential incorrect access of the buffer in a fragmented UDP packet (the packet would probably have to be deliberately pre-generated as fragmented) when AF_RXRPC tries to extract the contents of the SACK table by copying out the contents of the SACK table into a buffer before attempting to parse AF_RXRPC assumes that it can just call skb_condense() and then validly access the SACK table from skb->data and that it will be a flat buffer - but skb_condense() can silently fail to do anything under some circumstances. Note that whilst rxrpc_input_soft_acks() should be able to parse extended ACKs, the rest of AF_RXRPC doesn't currently support that. Further, there's then no need to call skb_condense() in rxrpc_input_ack(), so don't. Fixes: d57a3a151660 ("rxrpc: Save last ACK's SACK table rather than marking txbufs") Reported-by: Michael Bommarito Link: https://lore.kernel.org/r/20260513180907.2061972-1-michael.bommarito@gmail.com Signed-off-by: David Howells cc: Marc Dionne cc: Jeffrey Altman cc: Eric Dumazet cc: "David S. Miller" cc: Jakub Kicinski cc: Paolo Abeni cc: Simon Horman cc: linux-afs@lists.infradead.org cc: netdev@vger.kernel.org cc: stable@kernel.org Link: https://patch.msgid.link/105362.1780573560@warthog.procyon.org.uk Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- net/rxrpc/input.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -963,23 +963,34 @@ static void rxrpc_input_soft_acks(struct struct rxrpc_skb_priv *sp = rxrpc_skb(skb); struct rxrpc_txqueue *tq = call->tx_queue; unsigned long extracted = ~0UL; - unsigned int nr = 0; + unsigned int nr = 0, nsack; rxrpc_seq_t seq = call->acks_hard_ack + 1; rxrpc_seq_t lowest_nak = seq + sp->ack.nr_acks; - u8 *acks = skb->data + sizeof(struct rxrpc_wire_header) + sizeof(struct rxrpc_ackpacket); + u8 sack[256] __aligned(sizeof(unsigned long)); + u8 *acks = sack; _enter("%x,%x,%u", tq->qbase, seq, sp->ack.nr_acks); while (after(seq, tq->qbase + RXRPC_NR_TXQUEUE - 1)) tq = tq->next; + /* Extract an individual SACK table. A normal SACK table is up to 255 + * bytes with 1 ACK flag per byte, but an extended SACK table can be up + * to 256 bytes with up to 8 ACK/NACK flags per byte. The ACK flags go + * across all bit 0's then all bit 1's, then all bit 2's, ... + */ + memset(sack, 0, sizeof(sack)); + nsack = umin(sp->ack.nr_acks, 256); + if (skb_copy_bits(skb, + sizeof(struct rxrpc_wire_header) + sizeof(struct rxrpc_ackpacket), + sack, nsack) < 0) + return; + for (unsigned int i = 0; i < sp->ack.nr_acks; i++) { /* Decant ACKs until we hit a txqueue boundary. */ + if ((i & 255) == 0) + acks = sack; shiftr_adv_rotr(acks, extracted); - if (i == 256) { - acks -= i; - i = 0; - } seq++; nr++; if ((seq & RXRPC_TXQ_MASK) != 0) @@ -1117,9 +1128,6 @@ static void rxrpc_input_ack(struct rxrpc skb_copy_bits(skb, ioffset, &trailer, sizeof(trailer)) < 0) return rxrpc_proto_abort(call, 0, rxrpc_badmsg_short_ack_trailer); - if (nr_acks > 0) - skb_condense(skb); - call->acks_latest_ts = ktime_get_real(); call->acks_hard_ack = hard_ack; call->acks_prev_seq = prev_pkt;