The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=1ad21a6521827473dc6692646e9c760a5b0521cd
commit 1ad21a6521827473dc6692646e9c760a5b0521cd Author: Konstantin Belousov <[email protected]> AuthorDate: 2026-05-21 19:12:45 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2026-07-07 22:03:53 +0000 kern: add pddupfd(2) Reviewed by: markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D57163 --- sys/kern/kern_descrip.c | 8 +++-- sys/kern/sys_procdesc.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++ sys/kern/syscalls.master | 7 +++++ 3 files changed, 95 insertions(+), 2 deletions(-) diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index 351cc1917b04..8272d6da9b0a 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -3162,6 +3162,7 @@ fget_remote(struct thread *td, struct proc *p, int fd, struct filecaps *fcaps, struct filedesc *fdp; struct file *fp; int error; + bool copied __diagused; /* * Both fcaps and fd_flags must be either requested together, @@ -3186,8 +3187,11 @@ fget_remote(struct thread *td, struct proc *p, int fd, struct filecaps *fcaps, *fd_flags = fde_to_fd_flags(fdp->fd_ofiles[fd]. fde_flags); } - if (fcaps != NULL) - *fcaps = fdp->fd_ofiles[fd].fde_caps; + if (fcaps != NULL) { + copied = filecaps_copy( + &fdp->fd_ofiles[fd].fde_caps, fcaps, true); + MPASS(copied); + } error = 0; } else { error = EBADF; diff --git a/sys/kern/sys_procdesc.c b/sys/kern/sys_procdesc.c index 4749a9b8bf7e..7351df11c631 100644 --- a/sys/kern/sys_procdesc.c +++ b/sys/kern/sys_procdesc.c @@ -67,6 +67,7 @@ #include <sys/fcntl.h> #include <sys/file.h> #include <sys/filedesc.h> +#include <sys/imgact.h> #include <sys/kernel.h> #include <sys/lock.h> #include <sys/mutex.h> @@ -702,3 +703,84 @@ sys_pdopenpid(struct thread *td, struct pdopenpid_args *args) return (EINVAL); return (kern_pdopenpid(td, args->pid, args->flags)); } + +static int +kern_pddupfd(struct thread *td, int pdfd, int fd, int flags) +{ + struct proc *p; + struct file *fp, *pfp; + struct procdesc *pd; + struct filecaps fcaps; + uint8_t fd_flags; + int error, fdr; + + error = fget(td, pdfd, &cap_pddupfd_rights, &pfp); + if (error != 0) + return (error); + if (pfp->f_type != DTYPE_PROCDESC) { + error = EBADF; + goto out; + } + pd = pfp->f_data; +again: + sx_slock(&proctree_lock); + p = pd->pd_proc; + if (p != NULL) { + AUDIT_ARG_PROCESS(p); + PROC_LOCK(p); + sx_sunlock(&proctree_lock); + if ((p->p_flag & P_WEXIT) != 0) { + error = ESRCH; + } else { + /* + * Block the target process from entering + * execve(). We need to ensure that the + * p_candebug() predicate is stable until the + * fget_remote() call ends even after the + * process lock is dropped. For that, the + * process must not change uid/suid. + */ + if (!execve_block(td, p)) + goto again; + error = p_candebug(td, p); + if (error == 0) + _PHOLD(p); + else + execve_unblock(td, p); + } + PROC_UNLOCK(p); + if (error != 0) + goto out; + + error = fget_remote(td, p, fd, &fcaps, &fd_flags, &fp); + PROC_LOCK(p); + execve_unblock(td, p); + _PRELE(p); + PROC_UNLOCK(p); + if (error == 0) { + error = finstall_refed(td, fp, &fdr, O_CLOEXEC | + ((fd_flags & FD_RESOLVE_BENEATH) != 0 ? + O_RESOLVE_BENEATH : 0), &fcaps); + if (error != 0) { + fdrop(fp, td); + filecaps_free(&fcaps); + } else { + td->td_retval[0] = fdr; + } + } + } else { + sx_sunlock(&proctree_lock); + error = ESRCH; + } +out: + fdrop(pfp, td); + return (error); +} + +int +sys_pddupfd(struct thread *td, struct pddupfd_args *args) +{ + if (args->flags != 0) + return (EINVAL); + return (kern_pddupfd(td, args->pd, args->fd, args->flags)); +} diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master index 8ea32a7b0058..4bc5385f76e7 100644 --- a/sys/kern/syscalls.master +++ b/sys/kern/syscalls.master @@ -3435,5 +3435,12 @@ int flags ); } +604 AUE_NULL STD { + int pddupfd( + int pd, + int fd, + int flags + ); + } ; vim: syntax=off
