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| author | Christian Brauner <brauner@kernel.org> | 2026-10-05 10:09:33 -0500 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-10-12 10:58:20 +0200 |
| commit | be3a5e06b962ed056afb2be933817242a6ce32a5 (patch) | |
| tree | 3d4868edd28405b69d0f046f85d6e4f1c891c88e /include/linux | |
| parent | c48ae5bcfc356a8472132ad7fbdd5df83a34e8ac (diff) | |
| download | linux-next-be3a5e06b962ed056afb2be933817242a6ce32a5.tar.gz linux-next-be3a5e06b962ed056afb2be933817242a6ce32a5.zip | |
net: add SO_PASSPIDFD_THREAD to get a thread-specific SCM_PIDFD
Currently, SCM_PIDFD carries a pidfd for the thread-group leader. A
broker or the coredump server cannot learn the identity of the specific
thread that sent a given message. Now that both struct pids are recorded
a receiver can ask for the specific identity it needs.
So add SO_PASSPIDFD_THREAD as a sibling of SO_PASSPIDFD.
SO_PASSPIDFD_THREAD delivers an SCM_PIDFD_THREAD, i.e. scoped
to the specific thread sending. This is completely independent of
SO_PASSPIDFD, meaning you can use both options and get both cmsgs.
On SOCK_STREAM sockets recvmsg() only stops merging data at a thread
boundary when the receiver asked for a thread pidfd. For SO_PASSCRED and
SO_PASSPIDFD receivers all threads of one process remain a single
writer.
Co-developed-by: Andrew Halaney <andrew@amutable.com>
Signed-off-by: Andrew Halaney <andrew@amutable.com>
Link: https://patch.msgid.link/20261005-work-unix-passpidfd-v4-3-350183b6e02a@amutable.com
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/socket.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/socket.h b/include/linux/socket.h index 5a5eb1250103..b17fdb7d38a7 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -189,10 +189,11 @@ static inline size_t msg_data_left(const struct msghdr *msg) /* "Socket"-level control message types: */ -#define SCM_RIGHTS 0x01 /* rw: access rights (array of int) */ -#define SCM_CREDENTIALS 0x02 /* rw: struct ucred */ -#define SCM_SECURITY 0x03 /* rw: security label */ -#define SCM_PIDFD 0x04 /* ro: pidfd (int) */ +#define SCM_RIGHTS 0x01 /* rw: access rights (array of int) */ +#define SCM_CREDENTIALS 0x02 /* rw: struct ucred */ +#define SCM_SECURITY 0x03 /* rw: security label */ +#define SCM_PIDFD 0x04 /* ro: pidfd (int) */ +#define SCM_PIDFD_THREAD 0x05 /* ro: thread pidfd (int) */ struct ucred { __u32 pid; |