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 2F2AD33B6D1; Thu, 2 Jul 2026 16:38:21 +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=1783010302; cv=none; b=P4/Naewz8msp8/ZcHSoooE8ovpmAZWMBGMYzq/ygtSmdqdoH/6hdFXrb3qStDWHUp/9P5Er/XdsREXx6ll4dM+S5Xm1NJfYcxcHvkw5HdGxl4NSBwZpsMN3J1DsJms6sbK0W0VFMuZA5ESJ38OlQHtqMCPOa3NmkqBW7wPGK1Vo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783010302; c=relaxed/simple; bh=YbkMwQXx1OlomRdJyOYIG0eztRSycrAl4dbTUXUEekQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZHZWw1uNogj2JFedD6KGcPTd3Qu/euVk8x8jE66vWySkHZasDs0QZTHg4QlZiuUAG6k6XfjP4K5hGmDAPal6ocTeI+2sCADv7cd7OC7VHf9dOhzcHM7wCWVI872WwQbafRfDTFSoewwWA6lUok94DQOZLgSTS4tojPhU0TsAE9M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EM3nv1+f; 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="EM3nv1+f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BAA31F000E9; Thu, 2 Jul 2026 16:38:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783010301; bh=PtyvGxEYI8TFaymocx5DWgYaitw+9gSKjwsASF8ZahI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EM3nv1+fJUISf+D7qqcqkrUIp1dyuUh76etWuiTIWqvs+SCoQhp+SX2iMMYYYqbkj Yclaxk/SaNG0uBdgdAP9Ar+BXUm18X18/yYznCzlniJewqGV1akmZkMVjN+DbKVCHg 80dpTeUnZiCH5BzGnp+zoCsH0J2CG0IeGFW78VDU= 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, Sasha Levin Subject: [PATCH 6.12 055/204] rxrpc: Fix the ACK parser to extract the SACK table for parsing Date: Thu, 2 Jul 2026 18:18:32 +0200 Message-ID: <20260702155119.813722666@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155118.667618796@linuxfoundation.org> References: <20260702155118.667618796@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: netdev@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 333b6d5bb9f87827ac2639c737bf9613dbae7253 ] 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: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/rxrpc/input.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -775,9 +775,23 @@ static void rxrpc_input_soft_acks(struct rxrpc_seq_t since) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); - unsigned int i, old_nacks = 0; + unsigned int i, old_nacks = 0, nsack; 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; + + /* AF_RXRPC assumes that it can access the SACK table directly from + * skb->data as a flat buffer, but the skb may be non-linear (e.g. a + * fragmented UDP packet) and skb_condense() can silently fail to + * linearise it. Copy the SACK table out into a local buffer before + * parsing it. + */ + 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 (i = 0; i < sp->ack.nr_acks; i++) { if (acks[i] == RXRPC_ACK_TYPE_ACK) { @@ -934,9 +948,6 @@ 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); - if (call->cong_last_nack) { since = rxrpc_input_check_prev_ack(call, &summary, first_soft_ack); rxrpc_free_skb(call->cong_last_nack, rxrpc_skb_put_last_nack);