diff options
| author | Steffen Klassert <steffen.klassert@secunet.com> | 2022-03-07 13:11:39 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-28 08:41:42 +0200 |
| commit | ce89087966651ad41e103770efc5ce2742046284 (patch) | |
| tree | 4ac3171c99970f0d38d9db599531b7c27a418676 | |
| parent | 616e2dffaba372cf20b01172a73013ed28cbcc84 (diff) | |
| download | linux-stable-ce89087966651ad41e103770efc5ce2742046284.tar.gz | |
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.
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>
Signed-off-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/net/esp.h | 2 | ||||
| -rw-r--r-- | include/net/sock.h | 3 | ||||
| -rw-r--r-- | net/core/sock.c | 3 | ||||
| -rw-r--r-- | net/ipv4/esp4.c | 5 | ||||
| -rw-r--r-- | net/ipv6/esp6.c | 5 |
5 files changed, 15 insertions, 3 deletions
diff --git a/include/net/esp.h b/include/net/esp.h index 117652eb6ea3..465e38890ee9 100644 --- a/include/net/esp.h +++ b/include/net/esp.h @@ -4,6 +4,8 @@ #include <linux/skbuff.h> +#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 75677050c82e..2bf8dcf863f2 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2518,6 +2518,9 @@ extern int sysctl_optmem_max; extern __u32 sysctl_wmem_default; extern __u32 sysctl_rmem_default; +/* On 32bit arches, an skb frag is limited to 2^15 */ +#define SKB_FRAG_PAGE_ORDER get_order(32768) + static inline int sk_get_wmem0(const struct sock *sk, const struct proto *proto) { /* Does this proto have per netns sysctl_wmem ? */ diff --git a/net/core/sock.c b/net/core/sock.c index 41a77027a549..79f085df52ce 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2207,9 +2207,6 @@ static void sk_leave_memory_pressure(struct sock *sk) } } -/* On 32bit arches, an skb frag is limited to 2^15 */ -#define SKB_FRAG_PAGE_ORDER get_order(32768) - /** * skb_page_frag_refill - check that a page_frag contains enough room * @sz: minimum size of the fragment we want to get diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index 0792a9e2a555..45bb5b60b994 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -275,6 +275,7 @@ 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 UDP Encapsulation */ if (x->encap) { @@ -284,6 +285,10 @@ 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 25317d5ccf2c..e3abfc97fde7 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -241,6 +241,11 @@ 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 (!skb_cloned(skb)) { if (tailen <= skb_tailroom(skb)) { |