Commit 07881ccb authored by Florent Revest's avatar Florent Revest Committed by Alexei Starovoitov
Browse files

bpf: Be less specific about socket cookies guarantees 



Since "92acdc58 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: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarFlorent Revest <revest@chromium.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarKP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210210111406.785541-1-revest@chromium.org
parent 0e1aa629

include/uapi/linux/bpf.h

+4 −4
Original line number Diff line number Diff line
@@ -1656,22 +1656,22 @@ 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

tools/include/uapi/linux/bpf.h

+4 −4
Original line number Diff line number Diff line
@@ -1656,22 +1656,22 @@ 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