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-rw-r--r--lib/libsys/jail.2197
1 files changed, 187 insertions, 10 deletions
diff --git a/lib/libsys/jail.2 b/lib/libsys/jail.2
index 8f8b9925c712..ee4e5b03d38e 100644
--- a/lib/libsys/jail.2
+++ b/lib/libsys/jail.2
@@ -23,7 +23,7 @@
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
-.Dd November 29, 2023
+.Dd September 15, 2025
.Dt JAIL 2
.Os
.Sh NAME
@@ -31,7 +31,9 @@
.Nm jail_get ,
.Nm jail_set ,
.Nm jail_remove ,
-.Nm jail_attach
+.Nm jail_attach ,
+.Nm jail_remove_jd ,
+.Nm jail_attach_jd
.Nd create and manage system jails
.Sh LIBRARY
.Lb libc
@@ -44,6 +46,10 @@
.Fn jail_attach "int jid"
.Ft int
.Fn jail_remove "int jid"
+.Ft int
+.Fn jail_attach_jd "int fd"
+.Ft int
+.Fn jail_remove_jd "int fd"
.In sys/uio.h
.Ft int
.Fn jail_get "struct iovec *iov" "u_int niov" "int flags"
@@ -188,6 +194,29 @@ system call.
This is deprecated in
.Fn jail_set
and has no effect.
+.It Dv JAIL_USE_DESC
+Identify the jail by a descriptor in the
+.Va desc
+parameter.
+.It Dv JAIL_AT_DESC
+Operate in the context of the jail described by the
+.Va desc
+parameter, instead of the current jail.
+Only one of
+.Dv JAIL_USE_DESC
+or
+.Dv JAIL_AT_DESC
+may be specified.
+.It Dv JAIL_GET_DESC
+Return a new jail descriptor for the jail in the
+.Va desc
+parameter.
+.It Dv JAIL_OWN_DESC
+Return an
+.Dq owning
+jail descriptor in the
+.Va desc
+parameter.
.El
.Pp
The
@@ -221,6 +250,9 @@ arguments consists of one or more following flags:
.Bl -tag -width indent
.It Dv JAIL_DYING
Allow getting a jail that is in the process of being removed.
+.It Dv JAIL_USE_DESC , Dv JAIL_AT_DESC , Dv JAIL_GET_DESC , Dv JAIL_OWN_DESC
+These have the same meaning as they do in
+.Fn jail_set .
.El
.Pp
The
@@ -238,6 +270,76 @@ system call removes the jail identified by
.Fa jid .
It will kill all processes belonging to the jail, and remove any children
of that jail.
+.Pp
+The
+.Fn jail_attach_fd
+and
+.Fn jail_remove_fd
+system calls work the same as
+.Fn jail_attach
+and
+.Fn jail_remove ,
+except that they operate on the jail identified by jail descriptor
+.Fa fd .
+.Ss Jail Descriptors
+In addition to the jail ID,
+jails can be referred to using a jail descriptor,
+a type of file descriptor tied to a particular jail.
+Jail descriptors are created by calling
+.Fn jail_set
+or
+.Fn jail_get
+with the special parameter
+.Va desc ,
+and either the
+.Dv JAIL_GET_DESC
+or
+.Dv JAIL_OWN_DESC
+flags set.
+The difference between the two flags is that descriptors created with
+.Dv JAIL_OWN_DESC
+.Po
+called
+.Dq owning
+descriptors
+.Pc
+will automatically remove the jail when the descriptor is closed.
+.Pp
+Jail descriptors can be passed back to
+.Fn jail_set
+or
+.Fm jail_get
+with the
+.Va desc
+parameter,
+and either the
+.Dv JAIL_USE_DESC
+or
+.Dv JAIL_AT_DESC
+flags set.
+With
+.Dv JAIL_USE_DESC ,
+the descriptor identifies the jail to operate on,
+instead of the
+.Va jid
+or
+.Va name
+parameter.
+With
+.Dv JAIL_AT_DESC ,
+the descriptor is used in place of the current jail,
+allowing accessing or creating jails that are children of the
+descriptor jail.
+.Pp
+The system calls
+.Fn jail_attach_jd
+and
+.Fn jail_aremove_jd
+work the same as
+.Fn jail_attach
+and
+.Fn jail_remove ,
+except that they operate on the jail referred to by the passed descriptor.
.Sh RETURN VALUES
If successful,
.Fn jail ,
@@ -249,7 +351,7 @@ They return \-1 on failure, and set
.Va errno
to indicate the error.
.Pp
-.Rv -std jail_attach jail_remove
+.Rv -std jail_attach jail_remove jail_attach_jd jail_remove_jd
.Sh ERRORS
The
.Fn jail
@@ -281,6 +383,13 @@ the super-user, or because it would exceed the jail's
.Va children.max
limit.
.It Bq Er EPERM
+The jail descriptor in the
+.Va desc
+parameter was created by a user other than the super-user,
+and the
+.Dv JAIL_USE_DESC
+flag was set.
+.It Bq Er EPERM
A jail parameter was set to a less restrictive value then the current
environment.
.It Bq Er EFAULT
@@ -298,8 +407,12 @@ flag is not set.
.It Bq Er ENOENT
The jail referred to by a
.Va jid
-is not accessible by the process, because the process is in a different
-jail.
+parameter is not accessible by the process, because the process is in a
+different jail.
+.It Bq Er ENOENT
+The jail referred to by a
+.Va desc
+parameter has been removed.
.It Bq Er EEXIST
The jail referred to by a
.Va jid
@@ -326,6 +439,24 @@ flags is not set.
A supplied string parameter is longer than allowed.
.It Bq Er EAGAIN
There are no jail IDs left.
+.It Bq Er EMFILE
+A jail descriptor could not be created for the
+.Va desc
+parameter with either the
+.Dv JAIL_GET_DESC
+or
+.Dv JAIL_OWN_DESC
+flag set,
+because the process has already reached its limit for open file descriptors.
+.It Bq Er ENFILE
+A jail descriptor could not be created for the
+.Va desc
+parameter with either the
+.Dv JAIL_GET_DESC
+or
+.Dv JAIL_OWN_DESC
+flag set,
+because the system file table is full.
.El
.Pp
The
@@ -333,10 +464,6 @@ The
system call
will fail if:
.Bl -tag -width Er
-.It Bq Er EFAULT
-.Fa Iov ,
-or one of the addresses contained within it,
-points to an address outside the allocated address space of the process.
.It Bq Er ENOENT
The jail referred to by a
.Va jid
@@ -352,10 +479,37 @@ jail.
The
.Va lastjid
parameter is greater than the highest current jail ID.
+.It Bq Er ENOENT
+The jail referred to by a
+.Va desc
+parameter has been removed
+.Pq even if the Dv JAIL_CREATE flag has been set .
.It Bq Er EINVAL
A supplied parameter is the wrong size.
.It Bq Er EINVAL
+A supplied parameter is out of range.
+.It Bq Er EINVAL
+A supplied string parameter is not null-terminated.
+.It Bq Er EINVAL
A supplied parameter name does not match any known parameters.
+.It Bq Er EMFILE
+A jail descriptor could not be created for the
+.Va desc
+parameter with either the
+.Dv JAIL_GET_DESC
+or
+.Dv JAIL_OWN_DESC
+flag set,
+because the process has already reached its limit for open file descriptors.
+.It Bq Er ENFILE
+A jail descriptor could not be created for the
+.Va desc
+parameter with either the
+.Dv JAIL_GET_DESC
+or
+.Dv JAIL_OWN_DESC
+flag set,
+because the system file table is full.
.El
.Pp
The
@@ -373,14 +527,37 @@ The jail specified by
does not exist.
.El
.Pp
+The
+.Fn jail_attach_jd
+and
+.Fn jail_remove_jd
+system calls
+will fail if:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The
+.Fa fd
+argument is not a valid jail descriptor.
+.It Bq Er EPERM
+The jail descriptor was created by a user other than the super-user.
+.It Bq Er EINVAL
+The jail specified by
+.Fa jid
+has been removed.
+.El
+.Pp
Further
.Fn jail ,
.Fn jail_set ,
+.Fn jail_attach ,
and
-.Fn jail_attach
+.Fn jail_attach_jd
call
.Xr chroot 2
internally, so they can fail for all the same reasons.
+In particular, they return the
+.Bq Er EPERM
+error when the process to join a jail has open directories.
Please consult the
.Xr chroot 2
manual page for details.