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| author | jilles <jilles@FreeBSD.org> | 2013-04-07 15:26:09 +0000 |
|---|---|---|
| committer | jilles <jilles@FreeBSD.org> | 2013-04-07 15:26:09 +0000 |
| commit | fd361c8faa4d088e398aecb3ed9d37552daae541 (patch) | |
| tree | 6064a4b99420c0dc0525bd6f0aef8ee1284a7dc9 /sys/kern/uipc_sem.c | |
| parent | c29caa8936b8a2ba20b7c6109b82059b8da0dd36 (diff) | |
| download | FreeBSD-src-fd361c8faa4d088e398aecb3ed9d37552daae541.zip FreeBSD-src-fd361c8faa4d088e398aecb3ed9d37552daae541.tar.gz | |
mqueue,ksem,shm: Fix race condition with setting UF_EXCLOSE.
POSIX mqueue, compatibility ksem and POSIX shm create a file descriptor that
has close-on-exec set. However, they do this incorrectly, leaving a window
where a thread may fork and exec while the flag has not been set yet. The
race is easily reproduced on a multicore system with one thread doing
shm_open and close and another thread doing posix_spawnp and waitpid.
Set UF_EXCLOSE via falloc()'s flags argument instead. This also simplifies
the code.
MFC after: 1 week
Diffstat (limited to 'sys/kern/uipc_sem.c')
| -rw-r--r-- | sys/kern/uipc_sem.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/sys/kern/uipc_sem.c b/sys/kern/uipc_sem.c index 2de3409..509f32e 100644 --- a/sys/kern/uipc_sem.c +++ b/sys/kern/uipc_sem.c @@ -485,7 +485,7 @@ ksem_create(struct thread *td, const char *name, semid_t *semidp, mode_t mode, fdp = td->td_proc->p_fd; mode = (mode & ~fdp->fd_cmask) & ACCESSPERMS; - error = falloc(td, &fp, &fd, 0); + error = falloc(td, &fp, &fd, O_CLOEXEC); if (error) { if (name == NULL) error = ENOSPC; @@ -578,10 +578,6 @@ ksem_create(struct thread *td, const char *name, semid_t *semidp, mode_t mode, finit(fp, FREAD | FWRITE, DTYPE_SEM, ks, &ksem_ops); - FILEDESC_XLOCK(fdp); - if (fdp->fd_ofiles[fd].fde_file == fp) - fdp->fd_ofiles[fd].fde_flags |= UF_EXCLOSE; - FILEDESC_XUNLOCK(fdp); fdrop(fp, td); return (0); |
