[PATCH] aoe: pull in the headers each received packet type reads

[Josef Bacik <josef@toxicpanda.com>]

aoenet_rcv() only pulls the AoE and ATA headers into the skb head when
the packet is long enough to hold both.  A shorter packet goes through
unpulled, and aoenet_rcv() reads the AoE header from it anyway.  CFG
responses go on to aoecmd_cfg_rsp(), which reads the config header
after it, and ATA responses get queued for ktiocomplete(), which
skb_pull()s both headers.  Ethernet pads frames to 60 bytes, so this
mostly takes a virtual link, but nothing stops a short frame from
getting here.

Pull the AoE header up front and drop the packet if it isn't there,
then pull the ATA or config header in the switch arm that hands the
packet on, so each path gets the headers it reads.  This also replaces
the open-coded __pskb_pull_tail() with pskb_may_pull().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
Tested by sending AoE responses at a veth pair.  Without this patch a
26 byte CFG response and a 20 byte frame cut off inside the AoE header
each created an aoe device from bytes past the end of the packet.  With
it they're dropped, and a normal CFG response still creates the
device and gets an ATA identify back.

Thanks,
Josef
---
 drivers/block/aoe/aoenet.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/block/aoe/aoenet.c b/drivers/block/aoe/aoenet.c
index 66e617664c14..cd7c735bb43b 100644
--- a/drivers/block/aoe/aoenet.c
+++ b/drivers/block/aoe/aoenet.c
@@ -131,9 +131,7 @@ static int
 aoenet_rcv(struct sk_buff *skb, struct net_device *ifp, struct packet_type *pt, struct net_device *orig_dev)
 {
 	struct aoe_hdr *h;
-	struct aoe_atahdr *ah;
 	u32 n;
-	int sn;
 
 	if (dev_net(ifp) != &init_net)
 		goto exit;
@@ -144,12 +142,8 @@ aoenet_rcv(struct sk_buff *skb, struct net_device *ifp, struct packet_type *pt,
 	if (!is_aoe_netif(ifp))
 		goto exit;
 	skb_push(skb, ETH_HLEN);	/* (1) */
-	sn = sizeof(*h) + sizeof(*ah);
-	if (skb->len >= sn) {
-		sn -= skb_headlen(skb);
-		if (sn > 0 && !__pskb_pull_tail(skb, sn))
-			goto exit;
-	}
+	if (!pskb_may_pull(skb, sizeof(*h)))
+		goto exit;
 	h = (struct aoe_hdr *) skb->data;
 	n = get_unaligned_be32(&h->tag);
 	if ((h->verfl & AOEFL_RSP) == 0 || (n & 1<<31))
@@ -171,10 +165,14 @@ aoenet_rcv(struct sk_buff *skb, struct net_device *ifp, struct packet_type *pt,
 
 	switch (h->cmd) {
 	case AOECMD_ATA:
+		if (!pskb_may_pull(skb, sizeof(*h) + sizeof(struct aoe_atahdr)))
+			goto exit;
 		/* ata_rsp may keep skb for later processing or give it back */
 		skb = aoecmd_ata_rsp(skb);
 		break;
 	case AOECMD_CFG:
+		if (!pskb_may_pull(skb, sizeof(*h) + sizeof(struct aoe_cfghdr)))
+			goto exit;
 		aoecmd_cfg_rsp(skb);
 		break;
 	default:

---
base-commit: a3b346d7b1730db9900bb9e17f5bb8ea27e6ae2c
change-id: 20261006-b4-aoe-short-packets-f3e7d3580849