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| author | Mark Johnston <markj@FreeBSD.org> | 2021-09-07 18:51:54 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2021-09-07 21:12:09 +0000 |
| commit | a8aa6f1f784b91acb4ef9387a28c78311493eb66 (patch) | |
| tree | 747fbd0653871bbf83443d470d3a32c0f5926989 /sys/kern/uipc_syscalls.c | |
| parent | c4b44adcf0b631eb2d4187f285ed37cf4ce1caff (diff) | |
| download | src-a8aa6f1f784b91acb4ef9387a28c78311493eb66.tar.gz src-a8aa6f1f784b91acb4ef9387a28c78311493eb66.zip | |
socket: Avoid clearing SS_ISCONNECTING if soconnect() fails
This behaviour appears to date from the 4.4 BSD import. It has two
problems:
1. The update to so_state is not protected by the socket lock, so
concurrent updates to so_state may be lost.
2. Suppose two threads race to call connect(2) on a socket, and one
succeeds while the other fails. Then the failing thread may
incorrectly clear SS_ISCONNECTING, confusing the state machine.
Simply remove the update. It does not appear to be necessary:
pru_connect implementations which call soisconnecting() only do so after
all failure modes have been handled. For instance, tcp_connect() and
tcp6_connect() will never return an error after calling soisconnected().
However, we cannot correctly assert that SS_ISCONNECTED is not set after
an error from soconnect() since the socket lock is not held across the
pru_connect call, so a concurrent connect(2) may have set the flag.
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31699
Diffstat (limited to 'sys/kern/uipc_syscalls.c')
| -rw-r--r-- | sys/kern/uipc_syscalls.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c index 3208dc0491dd..44079bae1e9b 100644 --- a/sys/kern/uipc_syscalls.c +++ b/sys/kern/uipc_syscalls.c @@ -484,7 +484,7 @@ kern_connectat(struct thread *td, int dirfd, int fd, struct sockaddr *sa) { struct socket *so; struct file *fp; - int error, interrupted = 0; + int error; #ifdef CAPABILITY_MODE if (IN_CAPABILITY_MODE(td) && (dirfd == AT_FDCWD)) @@ -522,11 +522,8 @@ kern_connectat(struct thread *td, int dirfd, int fd, struct sockaddr *sa) while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) { error = msleep(&so->so_timeo, &so->so_lock, PSOCK | PCATCH, "connec", 0); - if (error != 0) { - if (error == EINTR || error == ERESTART) - interrupted = 1; + if (error != 0) break; - } } if (error == 0) { error = so->so_error; @@ -534,8 +531,6 @@ kern_connectat(struct thread *td, int dirfd, int fd, struct sockaddr *sa) } SOCK_UNLOCK(so); bad: - if (!interrupted) - so->so_state &= ~SS_ISCONNECTING; if (error == ERESTART) error = EINTR; done1: |