From f9aefd6b2aa38b9787d2705f0f1161dfd23cdb8f Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 20 Jun 2022 02:30:17 -0700
Subject: [PATCH] net: warn if mac header was not set
Make sure skb_mac_header(), skb_mac_offset() and skb_mac_header_len() uses
are not fooled if the mac header has not been set.
These checks are enabled if CONFIG_DEBUG_NET=y
This commit will likely expose existing bugs in linux networking stacks.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220620093017.3366713-1-eric.dumazet@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
include/linux/skbuff.h | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 82edf0359ab32..cd4a8268894ac 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2763,8 +2763,14 @@ static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
skb->network_header += offset;
}
+static inline int skb_mac_header_was_set(const struct sk_buff *skb)
+{
+ return skb->mac_header != (typeof(skb->mac_header))~0U;
+}
+
static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
{
+ DEBUG_NET_WARN_ON_ONCE(!skb_mac_header_was_set(skb));
return skb->head + skb->mac_header;
}
@@ -2775,14 +2781,10 @@ static inline int skb_mac_offset(const struct sk_buff *skb)
static inline u32 skb_mac_header_len(const struct sk_buff *skb)
{
+ DEBUG_NET_WARN_ON_ONCE(!skb_mac_header_was_set(skb));
return skb->network_header - skb->mac_header;
}
-static inline int skb_mac_header_was_set(const struct sk_buff *skb)
-{
- return skb->mac_header != (typeof(skb->mac_header))~0U;
-}
-
static inline void skb_unset_mac_header(struct sk_buff *skb)
{
skb->mac_header = (typeof(skb->mac_header))~0U;
--
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