From 1e4033b53db48cc77c436feac9c6d7d63db87b87 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Nov 2024 17:43:57 +0000 Subject: [PATCH 1/7] net: skb_reset_mac_len() must check if mac_header was set Recent discussions show that skb_reset_mac_len() should be more careful. We expect the MAC header being set. If not, clear skb->mac_len and fire a warning for CONFIG_DEBUG_NET=y builds. If after investigations we find that not having a MAC header was okay, we can remove the warning. Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/netdev/CANn89iJZGH+yEfJxfPWa3Hm7jxb-aeY2Up4HufmLMnVuQXt38A@mail.gmail.com/T/ Cc: En-Wei Wu Reviewed-by: Joe Damato Reviewed-by: Xuan Zhuo Link: https://patch.msgid.link/20241105174403.850330-2-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 48f1e0fa2a13..5d8fefa71cac 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2909,9 +2909,19 @@ static inline void skb_reset_inner_headers(struct sk_buff *skb) skb->inner_transport_header = skb->transport_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_reset_mac_len(struct sk_buff *skb) { - skb->mac_len = skb->network_header - skb->mac_header; + if (!skb_mac_header_was_set(skb)) { + DEBUG_NET_WARN_ON_ONCE(1); + skb->mac_len = 0; + } else { + skb->mac_len = skb->network_header - skb->mac_header; + } } static inline unsigned char *skb_inner_transport_header(const struct sk_buff @@ -3014,11 +3024,6 @@ 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)); From cfe8394e06f22847ecae0312bdd0b633b471b3f0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Nov 2024 17:43:58 +0000 Subject: [PATCH 2/7] net: add debug check in skb_reset_inner_transport_header() Make sure (skb->data - skb->head) can fit in skb->inner_transport_header This needs CONFIG_DEBUG_NET=y. Signed-off-by: Eric Dumazet Reviewed-by: Joe Damato Reviewed-by: Xuan Zhuo Link: https://patch.msgid.link/20241105174403.850330-3-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 5d8fefa71cac..75795568803c 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2937,7 +2937,10 @@ static inline int skb_inner_transport_offset(const struct sk_buff *skb) static inline void skb_reset_inner_transport_header(struct sk_buff *skb) { - skb->inner_transport_header = skb->data - skb->head; + long offset = skb->data - skb->head; + + DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->inner_transport_header))offset); + skb->inner_transport_header = offset; } static inline void skb_set_inner_transport_header(struct sk_buff *skb, From 1732e4bedb3e29986da6ea315e8bf8caf74e1e38 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Nov 2024 17:43:59 +0000 Subject: [PATCH 3/7] net: add debug check in skb_reset_inner_network_header() Make sure (skb->data - skb->head) can fit in skb->inner_network_header This needs CONFIG_DEBUG_NET=y. Signed-off-by: Eric Dumazet Reviewed-by: Joe Damato Reviewed-by: Xuan Zhuo Link: https://patch.msgid.link/20241105174403.850330-4-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 75795568803c..8dafd1295a6e 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2957,7 +2957,10 @@ static inline unsigned char *skb_inner_network_header(const struct sk_buff *skb) static inline void skb_reset_inner_network_header(struct sk_buff *skb) { - skb->inner_network_header = skb->data - skb->head; + long offset = skb->data - skb->head; + + DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->inner_network_header))offset); + skb->inner_network_header = offset; } static inline void skb_set_inner_network_header(struct sk_buff *skb, From 78a0cb2f45dc9327f26956c242f7f4b450efff49 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Nov 2024 17:44:00 +0000 Subject: [PATCH 4/7] net: add debug check in skb_reset_inner_mac_header() Make sure (skb->data - skb->head) can fit in skb->inner_mac_header This needs CONFIG_DEBUG_NET=y. Signed-off-by: Eric Dumazet Reviewed-by: Joe Damato Reviewed-by: Xuan Zhuo Link: https://patch.msgid.link/20241105174403.850330-5-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 8dafd1295a6e..32a7d8a65b9f 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2982,7 +2982,10 @@ static inline unsigned char *skb_inner_mac_header(const struct sk_buff *skb) static inline void skb_reset_inner_mac_header(struct sk_buff *skb) { - skb->inner_mac_header = skb->data - skb->head; + long offset = skb->data - skb->head; + + DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->inner_mac_header))offset); + skb->inner_mac_header = offset; } static inline void skb_set_inner_mac_header(struct sk_buff *skb, From ae50ea52bdd77eabd8f3c4630c1b03c3373f61a5 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Nov 2024 17:44:01 +0000 Subject: [PATCH 5/7] net: add debug check in skb_reset_transport_header() Make sure (skb->data - skb->head) can fit in skb->transport_header This needs CONFIG_DEBUG_NET=y. Signed-off-by: Eric Dumazet Reviewed-by: Joe Damato Reviewed-by: Xuan Zhuo Link: https://patch.msgid.link/20241105174403.850330-6-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 32a7d8a65b9f..f76524844e7e 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3007,7 +3007,10 @@ static inline unsigned char *skb_transport_header(const struct sk_buff *skb) static inline void skb_reset_transport_header(struct sk_buff *skb) { - skb->transport_header = skb->data - skb->head; + long offset = skb->data - skb->head; + + DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->transport_header))offset); + skb->transport_header = offset; } static inline void skb_set_transport_header(struct sk_buff *skb, From 305ae87dafc1a9f35374a783119d9e6001d1b8e0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Nov 2024 17:44:02 +0000 Subject: [PATCH 6/7] net: add debug check in skb_reset_network_header() Make sure (skb->data - skb->head) can fit in skb->network_header This needs CONFIG_DEBUG_NET=y. Signed-off-by: Eric Dumazet Reviewed-by: Joe Damato Reviewed-by: Xuan Zhuo Link: https://patch.msgid.link/20241105174403.850330-7-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f76524844e7e..f1e49a32880d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3027,7 +3027,10 @@ static inline unsigned char *skb_network_header(const struct sk_buff *skb) static inline void skb_reset_network_header(struct sk_buff *skb) { - skb->network_header = skb->data - skb->head; + long offset = skb->data - skb->head; + + DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->network_header))offset); + skb->network_header = offset; } static inline void skb_set_network_header(struct sk_buff *skb, const int offset) From 3b6167e9bfc9eae4edad065c166c667f9a8e693a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Nov 2024 17:44:03 +0000 Subject: [PATCH 7/7] net: add debug check in skb_reset_mac_header() Make sure (skb->data - skb->head) can fit in skb->mac_header This needs CONFIG_DEBUG_NET=y. Signed-off-by: Eric Dumazet Reviewed-by: Joe Damato Reviewed-by: Xuan Zhuo Link: https://patch.msgid.link/20241105174403.850330-8-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f1e49a32880d..e5095d75abba 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3063,7 +3063,10 @@ static inline void skb_unset_mac_header(struct sk_buff *skb) static inline void skb_reset_mac_header(struct sk_buff *skb) { - skb->mac_header = skb->data - skb->head; + long offset = skb->data - skb->head; + + DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->mac_header))offset); + skb->mac_header = offset; } static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)