Re: kernel panic with time-stamping in phy devices (monitor mode)

[Eric Dumazet <eric.dumazet@gmail.com>]

Le samedi 04 décembre 2010 à 12:46 -0800, Andrew Watts a écrit :

> Eric, I echo the thanks on the lightning patch.
> Impressive turnaround!
> 
> There's an open bug report on the kernel's bugzilla
> for 2.6.36 (#24102). What is the best way to tie these
> together?

Thanks Andy, here is the official patch submission I am going to make.

[PATCH net-2.6] net: fix skb_defer_rx_timestamp()

After commit c1f19b51d1d8 (net: support time stamping in phy devices.),
kernel might crash if CONFIG_NETWORK_PHY_TIMESTAMPING=y and
skb_defer_rx_timestamp() handles a packet without an ethernet header.

Fixes kernel bugzilla #24102

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=24102
Reported-and-tested-by: Andrew Watts <akwatts@ymail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: stable@kernel.org
---
 net/core/timestamping.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/core/timestamping.c b/net/core/timestamping.c
index 0ae6c22..c4fbf85 100644
--- a/net/core/timestamping.c
+++ b/net/core/timestamping.c
@@ -96,11 +96,13 @@ bool skb_defer_rx_timestamp(struct sk_buff *skb)
 	struct phy_device *phydev;
 	unsigned int type;
 
-	skb_push(skb, ETH_HLEN);
+	if (skb->data - ETH_HLEN < skb->head)
+		return false;
+	__skb_push(skb, ETH_HLEN);
 
 	type = classify(skb);
 
-	skb_pull(skb, ETH_HLEN);
+	__skb_pull(skb, ETH_HLEN);
 
 	switch (type) {
 	case PTP_CLASS_V1_IPV4: