[PATCH bpf-next v4 1/4] bpf: Be less specific about socket cookies guarantees

From: Florent Revest
Date: Wed Dec 09 2020 - 08:27:27 EST


Since "92acdc58ab11 bpf, net: Rework cookie generator as per-cpu one"
socket cookies are not guaranteed to be non-decreasing. The
bpf_get_socket_cookie helper descriptions are currently specifying that
cookies are non-decreasing but we don't want users to rely on that.

Reported-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx>
---
include/uapi/linux/bpf.h | 8 ++++----
tools/include/uapi/linux/bpf.h | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 30b477a26482..ba59309f4d18 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1650,22 +1650,22 @@ union bpf_attr {
* networking traffic statistics as it provides a global socket
* identifier that can be assumed unique.
* Return
- * A 8-byte long non-decreasing number on success, or 0 if the
- * socket field is missing inside *skb*.
+ * A 8-byte long unique number on success, or 0 if the socket
+ * field is missing inside *skb*.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
* Description
* Equivalent to bpf_get_socket_cookie() helper that accepts
* *skb*, but gets socket from **struct bpf_sock_addr** context.
* Return
- * A 8-byte long non-decreasing number.
+ * A 8-byte long unique number.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
* Description
* Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
* *skb*, but gets socket from **struct bpf_sock_ops** context.
* Return
- * A 8-byte long non-decreasing number.
+ * A 8-byte long unique number.
*
* u32 bpf_get_socket_uid(struct sk_buff *skb)
* Return
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 30b477a26482..ba59309f4d18 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1650,22 +1650,22 @@ union bpf_attr {
* networking traffic statistics as it provides a global socket
* identifier that can be assumed unique.
* Return
- * A 8-byte long non-decreasing number on success, or 0 if the
- * socket field is missing inside *skb*.
+ * A 8-byte long unique number on success, or 0 if the socket
+ * field is missing inside *skb*.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
* Description
* Equivalent to bpf_get_socket_cookie() helper that accepts
* *skb*, but gets socket from **struct bpf_sock_addr** context.
* Return
- * A 8-byte long non-decreasing number.
+ * A 8-byte long unique number.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
* Description
* Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
* *skb*, but gets socket from **struct bpf_sock_ops** context.
* Return
- * A 8-byte long non-decreasing number.
+ * A 8-byte long unique number.
*
* u32 bpf_get_socket_uid(struct sk_buff *skb)
* Return
--
2.29.2.576.ga3fc446d84-goog