Repository : ssh://git@open-mesh.org/batman-adv

On branches: maint,master

commit fb91b0ef84738102807e5dd7ec0b3565415aff56 Author: Sven Eckelmann sven@narfation.org Date: Sun Mar 18 13:12:01 2018 +0100

batman-adv: Fix skbuff rcsum on packet reroute

batadv_check_unicast_ttvn may redirect a packet to itself or another originator. This involves rewriting the ttvn and the destination address in the batadv unicast header. These field were not yet pulled (with skb rcsum update) and thus any change to them also requires a change in the receive checksum.

Reported-by: Matthias Schiffer mschiffer@universe-factory.net Fixes: cea194d90b11 ("batman-adv: improved client announcement mechanism") Signed-off-by: Sven Eckelmann sven@narfation.org

fb91b0ef84738102807e5dd7ec0b3565415aff56 compat-include/linux/skbuff.h | 12 ++++++++++++ compat-sources/net/core/skbuff.c | 17 ----------------- net/batman-adv/routing.c | 15 ++++++++++----- 3 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/compat-include/linux/skbuff.h b/compat-include/linux/skbuff.h index 1983dbe..6f73946 100644 --- a/compat-include/linux/skbuff.h +++ b/compat-include/linux/skbuff.h @@ -77,6 +77,18 @@ struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,

#endif /* < KERNEL_VERSION(4, 2, 0) */

+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 5, 0) + +static inline void skb_postpush_rcsum(struct sk_buff *skb, + const void *start, unsigned int len) +{ + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->csum = csum_block_add(skb->csum, + csum_partial(start, len, 0), 0); +} + +#endif /* < KERNEL_VERSION(4, 5, 0) */ + #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 13, 0)

static inline void *batadv_skb_put(struct sk_buff *skb, unsigned int len) diff --git a/compat-sources/net/core/skbuff.c b/compat-sources/net/core/skbuff.c index 3827f5c..30fbfbf 100644 --- a/compat-sources/net/core/skbuff.c +++ b/compat-sources/net/core/skbuff.c @@ -93,23 +93,6 @@ skb_checksum_validate(struct sk_buff *skb, int proto,

#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)

-static inline void skb_postpush_rcsum(struct sk_buff *skb, - const void *start, unsigned int len) -{ - /* For performing the reverse operation to skb_postpull_rcsum(), - * we can instead of ... - * - * skb->csum = csum_add(skb->csum, csum_partial(start, len, 0)); - * - * ... just use this equivalent version here to save a few - * instructions. Feeding csum of 0 in csum_partial() and later - * on adding skb->csum is equivalent to feed skb->csum in the - * first place. - */ - if (skb->ip_summed == CHECKSUM_COMPLETE) - skb->csum = csum_partial(start, len, skb->csum); -} - /** * skb_push_rcsum - push skb and update receive checksum * @skb: buffer to update diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index 0f10c56..cc3ed93 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -759,6 +759,7 @@ free_skb: /** * batadv_reroute_unicast_packet() - update the unicast header for re-routing * @bat_priv: the bat priv with all the soft interface information + * @skb: unicast packet to process * @unicast_packet: the unicast header to be updated * @dst_addr: the payload destination * @vid: VLAN identifier @@ -770,7 +771,7 @@ free_skb: * Return: true if the packet header has been updated, false otherwise */ static bool -batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, +batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb, struct batadv_unicast_packet *unicast_packet, u8 *dst_addr, unsigned short vid) { @@ -799,8 +800,10 @@ batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, }

/* update the packet header */ + skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet)); ether_addr_copy(unicast_packet->dest, orig_addr); unicast_packet->ttvn = orig_ttvn; + skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));

ret = true; out: @@ -841,7 +844,7 @@ static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv, * the packet to */ if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) { - if (batadv_reroute_unicast_packet(bat_priv, unicast_packet, + if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet, ethhdr->h_dest, vid)) batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv, @@ -887,7 +890,7 @@ static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv, * destination can possibly be updated and forwarded towards the new * target host */ - if (batadv_reroute_unicast_packet(bat_priv, unicast_packet, + if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet, ethhdr->h_dest, vid)) { batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv, "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n", @@ -910,12 +913,14 @@ static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv, if (!primary_if) return false;

+ /* update the packet header */ + skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet)); ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr); + unicast_packet->ttvn = curr_ttvn; + skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));

batadv_hardif_put(primary_if);

- unicast_packet->ttvn = curr_ttvn; - return true; }