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FAILED: patch "[PATCH] esp: Fix possible buffer overflow in ESP transformation" failed to apply to 5.10-stable tree

PATCH In review [email protected] 2 participants 5 messages Mar 14, 2022 – Mar 21, 2022

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[email protected]

author maintainer
#0 lore raw

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ebe48d368e97d007bfeb76fcb065d6cfc4c96645 Mon Sep 17 00:00:00 2001
From: Steffen Klassert <[email protected]>
Date: Mon, 7 Mar 2022 13:11:39 +0100
Subject: [PATCH] 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 <[email protected]>
Signed-off-by Steffen Klassert <[email protected]>
include/net/esp.h +2 -0
index 9c5637d41d95..90cd02ff77ef 100644
@@ -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)
net/ipv4/esp4.c +5 -0
index e1b1d080e908..70e6c87fbe3d 100644
@@ -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;
net/ipv6/esp6.c +5 -0
index 7591160edce1..b0ffbcd5432d 100644
@@ -482,6 +482,7 @@ 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;
 
 	if (x->encap) {
 		int err = esp6_output_encap(x, skb, esp);

@@ -490,6 +491,10 @@ int esp6_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;
#1 lore raw

PATCH 1/1 esp: Fix possible buffer overflow in ESP transformation

From: Steffen Klassert <[email protected]>

Plese apply this on 5.10.y stable as well as it fixes the following syzbot issues:

LINK https://syzkaller.appspot.com/bug?id=517fa734b92b7db404c409b924cf5c997640e324
LINK https://syzkaller.appspot.com/bug?id=57375340ab81a369df5da5eb16cfcd4aef9dfb9d

Here is a working patch.
---8<---

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.

Fixes cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Fixes 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible")
Reported-by valis <[email protected]>
Reported-by <[email protected]>
Signed-off-by Steffen Klassert <[email protected]>
Signed-off-by Tadeusz Struk <[email protected]>
---
 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(+)
include/net/esp.h +2 -0
index 9c5637d41d95..90cd02ff77ef 100644
@@ -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)
include/net/sock.h +1 -0
index d50823df426c..865e0ff20a81 100644
@@ -2688,6 +2688,7 @@ 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)
net/ipv4/esp4.c +5 -0
index 61dfb64e7256..b23b2bedca7a 100644
@@ -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;
net/ipv6/esp6.c +5 -0
index cb708fbb1c17..ffcc30484c8d 100644
@@ -483,6 +483,7 @@ 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;
 
 	if (x->encap) {
 		int err = esp6_output_encap(x, skb, esp);

@@ -491,6 +492,10 @@ int esp6_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;
Signature · 1 line
2.35.1
author maintainer
#2 lore raw

Re: [PATCH 5.10] esp: Fix possible buffer overflow in ESP transformation

Quoted 23 lines · Tadeusz Struk

From: Steffen Klassert <[email protected]>

Plese apply this on 5.10.y stable as well as it fixes the following syzbot issues:

LINK https://syzkaller.appspot.com/bug?id=517fa734b92b7db404c409b924cf5c997640e324
LINK https://syzkaller.appspot.com/bug?id=57375340ab81a369df5da5eb16cfcd4aef9dfb9d

Here is a working patch.
---8<---

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.

Fixes cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Fixes 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible")
Reported-by valis <[email protected]>
Reported-by <[email protected]>
Signed-off-by Steffen Klassert <[email protected]>
Signed-off-by Tadeusz Struk <[email protected]>
Quoted 6 lines
---
 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(+)

What is the git commit id of this commit in Linus's tree?

thanks,

greg k-h

#3 lore raw

Re: [PATCH 5.10] esp: Fix possible buffer overflow in ESP transformation

Quoted 31 lines · Greg KH
Quoted 23 lines · Tadeusz Struk

From: Steffen Klassert <[email protected]>

Plese apply this on 5.10.y stable as well as it fixes the following syzbot issues:

LINK https://syzkaller.appspot.com/bug?id=517fa734b92b7db404c409b924cf5c997640e324
LINK https://syzkaller.appspot.com/bug?id=57375340ab81a369df5da5eb16cfcd4aef9dfb9d

Here is a working patch.
---8<---

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.

Fixes cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Fixes 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible")
Reported-by valis <[email protected]>
Reported-by <[email protected]>
Signed-off-by Steffen Klassert <[email protected]>
Signed-off-by Tadeusz Struk <[email protected]>
Quoted 6 lines
---
  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(+)
Quoted 2 lines

What is the git commit id of this commit in Linus's tree?

It's this one:

ebe48d368e97 ("esp: Fix possible buffer overflow in ESP transformation")

Sorry I forgot to include it in the backport.

Signature · 2 lines
Thanks,
Tadeusz
author maintainer
#4 lore raw

Re: [PATCH 5.10] esp: Fix possible buffer overflow in ESP transformation

Quoted 32 lines · Tadeusz Struk
Quoted 31 lines · Greg KH
Quoted 29 lines · Tadeusz Struk

From: Steffen Klassert <[email protected]>

Plese apply this on 5.10.y stable as well as it fixes the following syzbot issues:

LINK https://syzkaller.appspot.com/bug?id=517fa734b92b7db404c409b924cf5c997640e324
LINK https://syzkaller.appspot.com/bug?id=57375340ab81a369df5da5eb16cfcd4aef9dfb9d

Here is a working patch.
---8<---

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.

Fixes cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Fixes 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible")
Reported-by valis <[email protected]>
Reported-by <[email protected]>
Signed-off-by Steffen Klassert <[email protected]>
Signed-off-by Tadeusz Struk <[email protected]>
---
  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(+)
Quoted 8 lines
Quoted 2 lines

What is the git commit id of this commit in Linus's tree?

It's this one:

ebe48d368e97 ("esp: Fix possible buffer overflow in ESP transformation")

Sorry I forgot to include it in the backport.

Now queued up, thanks.

gre gk-h