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| author | Steffen Klassert <steffen.klassert@secunet.com> | 2022-03-07 13:11:39 +0100 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2022-03-07 13:14:03 +0100 |
| commit | ebe48d368e97d007bfeb76fcb065d6cfc4c96645 (patch) | |
| tree | eaf068b3acda81ceaad0143fed5851d21a5e8bef /net/ipv4 | |
| parent | a3d9001b4e287fc043e5539d03d71a32ab114bcb (diff) | |
| download | linux-ebe48d368e97d007bfeb76fcb065d6cfc4c96645.tar.gz | |
esp: Fix possible buffer overflow in ESP transformation
The maximum message size that can be send is bigger than
the maximum site that skb_page_frag_refill can allocate.
So it is possible to write beyond the allocated buffer.
Fix this by doing a fallback to COW in that case.
v2:
Avoid get get_order() costs as suggested by Linus Torvalds.
Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible")
Reported-by: valis <sec@valis.email>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/esp4.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index e1b1d080e908..70e6c87fbe3d 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -446,6 +446,7 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info * struct page *page; struct sk_buff *trailer; int tailen = esp->tailen; + unsigned int allocsz; /* this is non-NULL only with TCP/UDP Encapsulation */ if (x->encap) { @@ -455,6 +456,10 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info * return err; } + allocsz = ALIGN(skb->data_len + tailen, L1_CACHE_BYTES); + if (allocsz > ESP_SKB_FRAG_MAXSIZE) + goto cow; + if (!skb_cloned(skb)) { if (tailen <= skb_tailroom(skb)) { nfrags = 1; |