Patch "net: core: reject skb_copy(_expand) for fraglist GSO skbs" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    net: core: reject skb_copy(_expand) for fraglist GSO skbs

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-core-reject-skb_copy-_expand-for-fraglist-gso-sk.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit c20135e549c203e364748c32ad857ec80808c659
Author: Felix Fietkau <nbd@xxxxxxxx>
Date:   Sat Apr 27 20:24:19 2024 +0200

    net: core: reject skb_copy(_expand) for fraglist GSO skbs
    
    [ Upstream commit d091e579b864fa790dd6a0cd537a22c383126681 ]
    
    SKB_GSO_FRAGLIST skbs must not be linearized, otherwise they become
    invalid. Return NULL if such an skb is passed to skb_copy or
    skb_copy_expand, in order to prevent a crash on a potential later
    call to skb_gso_segment.
    
    Fixes: 3a1296a38d0c ("net: Support GRO/GSO fraglist chaining.")
    Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 60876262b3fb3..f0a9ef1aeaa29 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1971,11 +1971,17 @@ static inline int skb_alloc_rx_flag(const struct sk_buff *skb)
 
 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
 {
-	int headerlen = skb_headroom(skb);
-	unsigned int size = skb_end_offset(skb) + skb->data_len;
-	struct sk_buff *n = __alloc_skb(size, gfp_mask,
-					skb_alloc_rx_flag(skb), NUMA_NO_NODE);
+	struct sk_buff *n;
+	unsigned int size;
+	int headerlen;
+
+	if (WARN_ON_ONCE(skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST))
+		return NULL;
 
+	headerlen = skb_headroom(skb);
+	size = skb_end_offset(skb) + skb->data_len;
+	n = __alloc_skb(size, gfp_mask,
+			skb_alloc_rx_flag(skb), NUMA_NO_NODE);
 	if (!n)
 		return NULL;
 
@@ -2303,12 +2309,17 @@ struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
 	/*
 	 *	Allocate the copy buffer
 	 */
-	struct sk_buff *n = __alloc_skb(newheadroom + skb->len + newtailroom,
-					gfp_mask, skb_alloc_rx_flag(skb),
-					NUMA_NO_NODE);
-	int oldheadroom = skb_headroom(skb);
 	int head_copy_len, head_copy_off;
+	struct sk_buff *n;
+	int oldheadroom;
+
+	if (WARN_ON_ONCE(skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST))
+		return NULL;
 
+	oldheadroom = skb_headroom(skb);
+	n = __alloc_skb(newheadroom + skb->len + newtailroom,
+			gfp_mask, skb_alloc_rx_flag(skb),
+			NUMA_NO_NODE);
 	if (!n)
 		return NULL;