43 lines
1.9 KiB
Diff
43 lines
1.9 KiB
Diff
From: Sven Eckelmann <sven@narfation.org>
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Date: Wed, 22 Jul 2020 20:49:23 +0200
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Subject: batman-adv: Avoid uninitialized chaddr when handling DHCP
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The gateway client code can try to optimize the delivery of DHCP packets to
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avoid broadcasting them through the whole mesh. But also transmissions to
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the client can be optimized by looking up the destination via the chaddr of
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the DHCP packet.
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But the chaddr is currently only done when chaddr is fully inside the
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non-paged area of the skbuff. Otherwise it will not be initialized and the
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unoptimized path should have been taken.
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But the implementation didn't handle this correctly. It didn't retrieve the
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correct chaddr but still tried to perform the TT lookup with this
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uninitialized memory.
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Reported-by: syzbot+ab16e463b903f5a37036@syzkaller.appspotmail.com
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Fixes: 2d5b555644b2 ("batman-adv: send every DHCP packet as bat-unicast")
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Signed-off-by: Sven Eckelmann <sven@narfation.org>
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Acked-by: Antonio Quartulli <a@unstable.cc>
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Signed-off-by: Sven Eckelmann <sven@narfation.org>
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Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/fcdf008ffd749246632d1f9423163af5dc3f8c7f
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diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
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index 140c61a3f1ecfec4fe23c5ddca19e18e2e86fd56..0c59fefc137196899f97e0fa7882cf55ceebe34c 100644
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--- a/net/batman-adv/gateway_client.c
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+++ b/net/batman-adv/gateway_client.c
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@@ -714,8 +714,10 @@ batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
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chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
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/* store the client address if the message is going to a client */
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- if (ret == BATADV_DHCP_TO_CLIENT &&
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- pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) {
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+ if (ret == BATADV_DHCP_TO_CLIENT) {
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+ if (!pskb_may_pull(skb, chaddr_offset + ETH_ALEN))
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+ return BATADV_DHCP_NO;
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+
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/* check if the DHCP packet carries an Ethernet DHCP */
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p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
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if (*p != BATADV_DHCP_HTYPE_ETHERNET)
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