From 3e71aa523eca0c44dace473b23f135c72c96a808 Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Mon, 7 Mar 2022 13:11:39 +0100 Subject: [PATCH] BACKPORT: esp: Fix possible buffer overflow in ESP transformation commit ebe48d368e97d007bfeb76fcb065d6cfc4c96645 upstream. 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. Bug: 227452856 Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Reported-by: valis Signed-off-by: Steffen Klassert Signed-off-by: Tadeusz Struk Signed-off-by: Greg Kroah-Hartman Change-Id: I2c7f97914138271e7788adfcebbd0b2b8b43cdcb Signed-off-by: Lee Jones --- include/net/esp.h | 2 ++ include/net/sock.h | 1 + net/ipv4/esp4.c | 5 +++++ net/ipv6/esp6.c | 5 +++++ 4 files changed, 13 insertions(+) diff --git a/include/net/esp.h b/include/net/esp.h index 9c5637d41d95..90cd02ff77ef 100644 --- a/include/net/esp.h +++ b/include/net/esp.h @@ -4,6 +4,8 @@ #include +#define ESP_SKB_FRAG_MAXSIZE (PAGE_SIZE << SKB_FRAG_PAGE_ORDER) + struct ip_esp_hdr; static inline struct ip_esp_hdr *ip_esp_hdr(const struct sk_buff *skb) diff --git a/include/net/sock.h b/include/net/sock.h index 738981f7b565..eb64ca0f01f3 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2691,6 +2691,7 @@ extern int sysctl_optmem_max; extern __u32 sysctl_wmem_default; extern __u32 sysctl_rmem_default; +#define SKB_FRAG_PAGE_ORDER get_order(32768) DECLARE_STATIC_KEY_FALSE(net_high_order_alloc_disable_key); static inline int sk_get_wmem0(const struct sock *sk, const struct proto *proto) diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index a3271ec3e162..d76af5ba5cc2 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -448,6 +448,7 @@ 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) { @@ -457,6 +458,10 @@ 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; diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index 0158b0163ca8..f5d40fabad0b 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -483,6 +483,11 @@ int esp6_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; + + allocsz = ALIGN(skb->data_len + tailen, L1_CACHE_BYTES); + if (allocsz > ESP_SKB_FRAG_MAXSIZE) + goto cow; if (x->encap) { int err = esp6_output_encap(x, skb, esp);