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procctl.2: Editing pass

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- Add some missing .Pp macros after the end of literal blocks and some
  lists to ensure there is a blank line before the following text.

- Use an indent of Ds for nested lists to reduce excessive indentation and
  make the bodies of the nested list items easier to read.

- Various and sundry rewordings and clarifications.

Reviewed by:	kib, emaste
Differential Revision:	https://reviews.freebsd.org/D47782

(cherry picked from commit 8277c790179304159c2e4dcb1d99552518d5be8e)
This commit is contained in:
John Baldwin 2024-12-04 09:11:19 -05:00
parent 9a15a1fef9
commit 66cb373c8f
1 changed files with 244 additions and 168 deletions
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412
lib/libc/sys/procctl.2
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@ -27,7 +27,7 @@
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd October 26, 2023
.Dd December 4, 2024
.Dt PROCCTL 2
.Os
.Sh NAME
@ -72,16 +72,16 @@ The control request to perform is specified by the
argument.
.Pp
All status changing requests
.Dv *_CTL
.Pq Dv *_CTL
require the caller to have the right to debug the target.
All status query requests
.Dv *_STATUS
.Pq Dv *_STATUS
require the caller to have the right to observe the target.
.Pp
The following commands are supported:
.Bl -tag -width PROC_TRAPCAP_STATUS
.It Dv PROC_ASLR_CTL
Controls the Address Space Layout Randomization (ASLR) in the program
Controls Address Space Layout Randomization (ASLR) in program
images created
by
.Xr execve 2
@ -89,28 +89,35 @@ in the specified process or its descendants that do not either change
the control or modify it by other means.
The
.Fa data
parameter must point to the integer variable holding one of the following
parameter must point to an integer variable holding one of the following
values:
.Bl -tag -width PROC_ASLR_FORCE_DISABLE
.Bl -tag -width Ds
.It Dv PROC_ASLR_FORCE_ENABLE
Request that ASLR is enabled after execution, even if it is disabled
system-wide.
The image flag and set-uid might prevent ASLR enablement still.
.It Dv PROC_ASLR_FORCE_DISABLE
Request that ASLR is disabled after execution.
Same notes as for
.Dv PROC_ASLR_FORCE_ENABLE
apply.
Request that ASLR is disabled after execution, even if it is enabled
system-wide.
.It Dv PROC_ASLR_NOFORCE
Use the system-wide configured policy for ASLR.
.El
.Pp
Note that the
.Xr elfctl 1
.Dq noaslr
flag takes precedence over this control.
Executing a binary with this flag set will never use ASLR.
Similarly, executing a set-user-ID or set-group-ID binary ignores this
control and only honors the
.Xr elfctl 1
flag and system-wide policy.
.It Dv PROC_ASLR_STATUS
Returns the current status of ASLR enablement for the target process.
The
.Fa data
parameter must point to the integer variable, where one of the
parameter must point to an integer variable, where one of the
following values is written:
.Bl -tag -width PROC_ASLR_FORCE_DISABLE
.Bl -tag -width Ds
.It Dv PROC_ASLR_FORCE_ENABLE
.It Dv PROC_ASLR_FORCE_DISABLE
.It Dv PROC_ASLR_NOFORCE
@ -121,56 +128,79 @@ the
.Dv PROC_ASLR_ACTIVE
flag is or-ed with the value listed above.
.It Dv PROC_PROTMAX_CTL
Controls implicit application of PROT_MAX protection equal to the
.Fa prot
argument of the
Controls the maximum protection used for
.Xr mmap 2
syscall, in the target process.
requests in the target process that do not specify
an explicit maximum protection in the
.Fa prot
argument via
.Dv PROT_MAX .
The maximum protection limits the permissions a mapping can be assigned by
.Xr mprotect 2 .
If an explicit maximum protection is not provided,
the maximum protection for a new mapping is set to either
.Dv PROT_READ | PROT_WRITE | PROT_EXEC
.Pq RWX
or the protection specified in
.Fa prot .
Mappings created with
.Fa prot
set to
.Dv PROT_NONE
always use RWX maximum protection.
.Pp
The
.Fa data
parameter must point to the integer variable holding one of the following
parameter must point to an integer variable holding one of the following
values:
.Bl -tag -width PROC_PROTMAX_FORCE_DISABLE
.Bl -tag -width Ds
.It Dv PROC_PROTMAX_FORCE_ENABLE
Enables implicit PROT_MAX application,
even if it is disabled system-wide by the sysctl
Use the permissions in
.Fa prot
as the implicit maximum protection,
even if RWX permissions are requested by the sysctl
.Va vm.imply_prot_max .
The image flag might still prevent the enablement.
.It Dv PROC_PROTMAX_FORCE_DISABLE
Request that implicit application of PROT_MAX be disabled.
Same notes as for
.Dv PROC_PROTMAX_FORCE_ENABLE
apply.
Use RWX as the implicit maximum protection,
even if constrained permissions are requested by the sysctl
.Va vm.imply_prot_max .
.It Dv PROC_PROTMAX_NOFORCE
Use the system-wide configured policy for PROT_MAX.
Use the system-wide configured policy for the implicit PROT_MAX control.
.El
.Pp
Note that the
.Xr elfctl 1
.Dq noprotmax
flag takes precedence over this control.
Executing a binary with this flag set will always use RWX as the implicit
maximum protection.
.It Dv PROC_PROTMAX_STATUS
Returns the current status of implicit PROT_MAX enablement for the
Returns the current status of the implicit PROT_MAX control for the
target process.
The
.Fa data
parameter must point to the integer variable, where one of the
parameter must point to an integer variable, where one of the
following values is written:
.Bl -tag -width PROC_PROTMAX_FORCE_DISABLE
.Bl -tag -width Ds
.It Dv PROC_PROTMAX_FORCE_ENABLE
.It Dv PROC_PROTMAX_FORCE_DISABLE
.It Dv PROC_PROTMAX_NOFORCE
.El
.Pp
If the currently executed image in the process itself has implicit PROT_MAX
application enabled, the
If the currently executed image in the process itself has the implicit PROT_MAX
control enabled, the
.Dv PROC_PROTMAX_ACTIVE
flag is or-ed with the value listed above.
.It Dv PROC_SPROTECT
Set process protection state.
This is used to mark a process as protected from being killed if the system
exhausts the available memory and swap.
exhausts available memory and swap.
The
.Fa data
parameter must point to an integer containing an operation and zero or more
optional flags.
The following operations are supported:
.Bl -tag -width PPROT_CLEAR
.Bl -tag -width Ds
.It Dv PPROT_SET
Mark the selected processes as protected.
.It Dv PPROT_CLEAR
@ -178,7 +208,7 @@ Clear the protected state of selected processes.
.El
.Pp
The following optional flags are supported:
.Bl -tag -width PPROT_DESCEND
.Bl -tag -width Ds
.It Dv PPROT_DESCEND
Apply the requested operation to all child processes of each selected process
in addition to each selected process.
@ -189,25 +219,41 @@ mark all future child processes of each selected process as protected.
Future child processes will also mark all of their future child processes.
.El
.It Dv PROC_REAP_ACQUIRE
Acquires the reaper status for the current process.
Reaper status means that children orphaned by the reaper's descendants
that were forked after the acquisition of reaper status are reparented to the
reaper process.
Enable orphaned process reaping for future children of the current process.
.Pp
If a parent process exits before one or more of its children processes,
the remaining children processes are orphaned.
When an orphaned process exits,
it is reparented to a reaper process that is responsible for harvesting
the terminated process via
.Xr wait 2 .
When this control is enabled,
the current process becomes the reaper process for future children and their
descendants.
Existing child processes continue to use the reaper assigned when the child
was created via
.Xr fork 2 .
If a reaper process exits,
all of the processes for whom it was the reaper are reassigned to the reaper
process's reaper.
.Pp
After system initialization,
.Xr init 8
is the default reaper.
.It Dv PROC_REAP_RELEASE
Release the reaper state for the current process.
The reaper of the current process becomes the new reaper of the
current process's descendants.
Disable orphaned process reaping for the current process.
.Pp
Any processes for whom the current process was the reaper are reassigned to
the current process's reaper.
.It Dv PROC_REAP_STATUS
Provides information about the reaper of the specified process,
or the process itself when it is a reaper.
Provides a consistent snapshot of information about the reaper
of the specified process,
or the process itself if it is a reaper.
The
.Fa data
argument must point to a
.Vt procctl_reaper_status
structure which is filled in by the syscall on successful return.
structure which is filled in by the system call on successful return.
.Bd -literal
struct procctl_reaper_status {
u_int rs_flags;
@ -217,16 +263,16 @@ struct procctl_reaper_status {
pid_t rs_pid;
};
.Ed
.Pp
The
.Fa rs_flags
may have the following flags returned:
.Bl -tag -width REAPER_STATUS_REALINIT
.Bl -tag -width Ds
.It Dv REAPER_STATUS_OWNED
The specified process has acquired reaper status and has not
released it.
When the flag is returned, the specified process
The specified process is a reaper.
When this flag is returned, the specified process
.Fa id ,
pid, identifies the reaper, otherwise the
pid, identifies a reaper, otherwise the
.Fa rs_reaper
field of the structure is set to the pid of the reaper
for the specified process id.
@ -237,23 +283,25 @@ The specified process is the root of the reaper tree, i.e.,
.Pp
The
.Fa rs_children
field returns the number of children of the reaper among the descendants.
field returns the number of processes that can be reaped by the reaper that
are also children of the reaper.
It is possible to have a child whose reaper is not the specified process,
since the reaper for any existing children is not reset on the
.Dv PROC_REAP_ACQUIRE
operation.
since the reaper for existing children is not changed by
.Dv PROC_REAP_ACQUIRE .
The
.Fa rs_descendants
field returns the total number of descendants of the reaper(s),
not counting descendants of the reaper in the subtree.
field returns the total number of processes that can be reaped by the reaper.
The
.Fa rs_reaper
field returns the reaper pid.
field returns the reaper's pid.
The
.Fa rs_pid
returns the pid of one reaper child if there are any descendants.
returns the pid of one reaper child if there are any processes that can be
reapead;
otherwise, it is set to \-1.
.It Dv PROC_REAP_GETPIDS
Queries the list of descendants of the reaper of the specified process.
Queries the list of processes that can be reaped
by the reaper of the specified process.
The request takes a pointer to a
.Vt procctl_reaper_pids
structure in the
@ -265,17 +313,15 @@ struct procctl_reaper_pids {
struct procctl_reaper_pidinfo *rp_pids;
};
.Ed
.Pp
When called, the
.Fa rp_pids
field must point to an array of
.Fa rp_count
.Vt procctl_reaper_pidinfo
structures, to be filled in on return,
and the
.Fa rp_count
field must specify the size of the array,
into which no more than
.Fa rp_count
elements will be filled in by the kernel.
structures.
The kernel will populate these structures with information about the
reaper's descendants.
.Pp
The
.Vt "struct procctl_reaper_pidinfo"
@ -290,17 +336,18 @@ struct procctl_reaper_pidinfo {
u_int pi_flags;
};
.Ed
.Pp
The
.Fa pi_pid
field is the process id of the descendant.
The
.Fa pi_subtree
field provides the pid of the child of the reaper, which is the (grand-)parent
of the process.
field provides the pid of the direct child of the reaper which is
the (grand-)parent of the descendant process.
The
.Fa pi_flags
field returns the following flags, further describing the descendant:
.Bl -tag -width REAPER_PIDINFO_EXITING
.Bl -tag -width Ds
.It Dv REAPER_PIDINFO_VALID
Set to indicate that the
.Vt procctl_reaper_pidinfo
@ -314,7 +361,7 @@ of the returned array.
.It Dv REAPER_PIDINFO_CHILD
The
.Fa pi_pid
field identifies the direct child of the reaper.
field identifies a direct child of the reaper.
.It Dv REAPER_PIDINFO_REAPER
The reported process is itself a reaper.
The descendants of the subordinate reaper are not reported.
@ -341,6 +388,7 @@ struct procctl_reaper_kill {
pid_t rk_fpid;
};
.Ed
.Pp
The
.Fa rk_sig
field specifies the signal to be delivered.
@ -350,7 +398,7 @@ The
.Fa rk_flags
field further directs the operation.
It is or-ed from the following flags:
.Bl -tag -width REAPER_KILL_CHILDREN
.Bl -tag -width Ds
.It Dv REAPER_KILL_CHILDREN
Deliver the specified signal only to direct children of the reaper.
.It Dv REAPER_KILL_SUBTREE
@ -359,6 +407,7 @@ the direct child with pid specified in the
.Fa rk_subtree
field.
.El
.Pp
If neither the
.Dv REAPER_KILL_CHILDREN
nor the
@ -376,22 +425,22 @@ field is set to the pid of the first process for which signal
delivery failed, e.g., due to permission problems.
If no such process exists, the
.Fa rk_fpid
field is set to -1.
field is set to \-1.
.It Dv PROC_TRACE_CTL
Enable or disable tracing of the specified process(es), according to the
value of the integer argument.
Tracing includes attachment to the process using the
.Xr ptrace 2
and
Tracing includes inspecting the process via
.Xr ptrace 2 ,
.Xr ktrace 2 ,
debugging sysctls,
.Xr hwpmc 4 ,
.Xr dtrace 1 ,
and core dumping.
or
.Xr dtrace 1
as well as dumping core.
Possible values for the
.Fa data
argument are:
.Bl -tag -width PROC_TRACE_CTL_DISABLE_EXEC
.Bl -tag -width Ds
.It Dv PROC_TRACE_CTL_ENABLE
Enable tracing, after it was disabled by
.Dv PROC_TRACE_CTL_DISABLE .
@ -401,7 +450,7 @@ Disable tracing for the specified process.
Tracing is re-enabled when the process changes the executing
program with the
.Xr execve 2
syscall.
system call.
A child inherits the trace settings from the parent on
.Xr fork 2 .
.It Dv PROC_TRACE_CTL_DISABLE_EXEC
@ -416,10 +465,10 @@ the integer variable pointed to by
.Fa data .
If tracing is disabled,
.Fa data
is set to -1.
is set to \-1.
If tracing is enabled, but no debugger is attached by the
.Xr ptrace 2
syscall,
system call,
.Fa data
is set to 0.
If a debugger is attached,
@ -427,23 +476,24 @@ If a debugger is attached,
is set to the pid of the debugger process.
.It Dv PROC_TRAPCAP_CTL
Controls the capability mode sandbox actions for the specified
sandboxed processes,
on a return from any syscall which gives either a
sandboxed processes
on a return from any system call which fails with either an
.Er ENOTCAPABLE
or
.Er ECAPMODE
error.
If the control is enabled, such errors from the syscalls cause
delivery of the synchronous
If this control is enabled and a system call fails with one of these errors,
a synchronous
.Dv SIGTRAP
signal to the thread immediately before returning from the syscalls.
signal is delivered to the thread immediately before returning from the
system call.
.Pp
Possible values for the
.Fa data
argument are:
.Bl -tag -width PROC_TRAPCAP_CTL_DISABLE
.Bl -tag -width Ds
.It Dv PROC_TRAPCAP_CTL_ENABLE
Enable the
Enable
.Dv SIGTRAP
signal delivery on capability mode access violations.
The enabled mode is inherited by the children of the process,
@ -451,7 +501,9 @@ and is kept after
.Xr fexecve 2
calls.
.It Dv PROC_TRAPCAP_CTL_DISABLE
Disable the signal delivery on capability mode access violations.
Disable
.Dv SIGTRAP
signal delivery on capability mode access violations.
Note that the global sysctl
.Dv kern.trap_enotcap
might still cause the signal to be delivered.
@ -463,7 +515,7 @@ On signal delivery, the
.Va si_errno
member of the
.Fa siginfo
signal handler parameter is set to the syscall error value,
signal handler parameter is set to the system call error value,
and the
.Va si_code
member is set to
@ -481,15 +533,18 @@ signal handler.
.Pp
See
.Xr capsicum 4
for more information about the capability mode.
for more information about capability mode.
.It Dv PROC_TRAPCAP_STATUS
Return the current status of signalling capability mode access
violations for the specified process.
Return the current status of raising
.Dv SIGTRAP
for capability mode access violations by the specified process.
The integer value pointed to by the
.Fa data
argument is set to the
.Dv PROC_TRAPCAP_CTL_ENABLE
value if the process control enables signal delivery, and to
value if
.Dv SIGTRAP
delivery is enabled, and to
.Dv PROC_TRAPCAP_CTL_DISABLE
otherwise.
.Pp
@ -528,39 +583,42 @@ must point to a memory location that can hold a value of type
If signal delivery has not been requested, it will contain zero
on return.
.It Dv PROC_STACKGAP_CTL
Controls the stack gaps in the specified process.
A stack gap is the part of the growth area for a
Controls stack gaps in the specified process.
A stack gap is one or more virtual memory pages at the end of the
growth area for a
.Dv MAP_STACK
mapped region that is reserved and never filled by memory.
Instead, the process is guaranteed to receive a
mapping that is reserved and never backed by memory.
Instead, the process is guaranteed to receive a synchronous
.Dv SIGSEGV
signal on accessing pages in the gap.
Gaps protect against stack overflow corrupting memory adjacent
to the stack.
signal for each access to pages in the gap.
The number of pages reserved for each stack is set by the sysctl
.Va security.bsd.stack_guard_page .
.Pp
Gaps protect against stack overflows by preventing them from corrupting memory
adjacent to the stack.
.Pp
The
.Fa data
argument must point to an integer variable containing flags.
The following flags are allowed:
.Bl -tag -width PROC_STACKGAP_DISABLE_EXEC
.Bl -tag -width Ds
.It Dv PROC_STACKGAP_ENABLE
This flag is only accepted for consistency with
.Dv PROC_STACKGAP_STATUS .
If stack gaps are enabled, the flag is ignored.
If disabled, the flag causes an
.Ev EINVAL
error to be returned.
If stack gaps are disabled, the request fails with
.Ev EINVAL .
After gaps are disabled in a process, they can only be re-enabled when an
.Xr execve 2
is performed.
.It Dv PROC_STACKGAP_DISABLE
Disable stack gaps for the process.
For existing stacks, the gap is no longer a reserved part of the growth
area and can be filled by memory on access.
For existing stacks, the gap is no longer reserved
and can be filled by memory on access.
.It Dv PROC_STACKGAP_ENABLE_EXEC
Enable stack gaps for programs started after an
Enable stack gaps for the new address space constructed by any future
.Xr execve 2
by the specified process.
in the specified process.
.It Dv PROC_STACKGAP_DISABLE_EXEC
Inherit disabled stack gaps state after
.Xr execve 2 .
@ -576,7 +634,7 @@ Returns the current stack gap state for the specified process.
.Fa data
must point to an integer variable, which is used to return a bitmask
consisting of the following flags:
.Bl -tag -width PROC_STACKGAP_DISABLE_EXEC
.Bl -tag -width Ds
.It Dv PROC_STACKGAP_ENABLE
Stack gaps are enabled.
.It Dv PROC_STACKGAP_DISABLE
@ -588,82 +646,99 @@ Stack gaps are enabled in the process after
Stack gaps are disabled in the process after
.Xr execve 2 .
.El
.Pp
Note that the
.Xr elfctl 1
.Dq nostackgap
flag takes precedence over this setting for individual process address spaces.
Executing a binary with this flag set will never use stack gaps in the address
space constructed by
.Xr execve 2 .
However, the controls value can still be inherited by child processes, and
executing a binary without this flag set will revert to the behavior specified
by the control.
.It Dv PROC_NO_NEW_PRIVS_CTL
Allows one to ignore the SUID and SGID bits on the program
Allows one to ignore the set-user-ID and set-group-ID bits on the program
images activated by
.Xr execve 2
in the specified process and its future descendants.
The
.Fa data
parameter must point to the integer variable holding the following
parameter must point to an integer variable holding the following
value:
.Bl -tag -width PROC_NO_NEW_PRIVS_ENABLE
.Bl -tag -width Ds
.It Dv PROC_NO_NEW_PRIVS_ENABLE
Request SUID and SGID bits to be ignored.
Request set-user-ID and set-group-ID bits to be ignored.
.El
.Pp
It is not possible to disable it once it has been enabled.
It is not possible to disable this control once it has been enabled.
.It Dv PROC_NO_NEW_PRIVS_STATUS
Returns the current status of SUID/SGID enablement for the target process.
Returns the current status of set-ID bits enablement for the target process.
The
.Fa data
parameter must point to the integer variable, where one of the
parameter must point to an integer variable, where one of the
following values is written:
.Bl -tag -width PROC_NO_NEW_PRIVS_DISABLE
.Bl -tag -width Ds
.It Dv PROC_NO_NEW_PRIVS_ENABLE
.It Dv PROC_NO_NEW_PRIVS_DISABLE
.El
.It Dv PROC_WXMAP_CTL
Controls the 'write exclusive against execution' permissions for the
mappings in the process address space.
It overrides the global settings established by the
.Dv kern.elf{32/64}.allow_wx
sysctl,
and the corresponding bit in the ELF control note, see
.Xr elfctl 1 .
.Pp
Controls the creation of mappings with both write and execute permissions
in a process's address space.
The
.Fa data
parameter must point to the integer variable holding one of the
parameter must point to an integer variable holding one of the
following values:
.Bl -tag -width PROC_WX_MAPPINGS_DISALLOW_EXEC
.Bl -tag -width Ds
.It Dv PROC_WX_MAPPINGS_PERMIT
Enable creation of mappings that have both write and execute
protection attributes, in the specified process' address space.
permissions in the specified process' current and future address spaces.
.It Dv PROC_WX_MAPPINGS_DISALLOW_EXEC
In the new address space created by
In a new address space created by a future call to
.Xr execve 2 ,
disallow creation of mappings that have both write and execute
permissions.
.El
.Pp
Once creation of writeable and executable mappings is allowed,
it is impossible (and pointless) to disallow it.
If both flags are set,
.Dv PROC_WX_MAPPINGS_DISALLOW_EXEC
takes precedence during
.Xr execve 2 .
If neither flag is set,
mappings with write and execute permissions are only permitted if the
.Dv kern.elf{32/64}.allow_wx
sysctl is non-zero or the
.Xr elfctl 1
.Dq wxneeded
flag is set in the ELF control note.
.Pp
Once creation of writeable and executable mappings is enabled for a process,
it is impossible (and pointless) to disable it.
The only way to ensure the absence of such mappings after they
were enabled in a given process, is to set the
were enabled in a given process is to set the
.Dv PROC_WX_MAPPINGS_DISALLOW_EXEC
flag and
.Xr execve 2
an image.
.It Dv PROC_WXMAP_STATUS
Returns the current status of the 'write exclusive against execution'
enforcement for the specified process.
Returns the current status of the controls over creation of mappings with
both write and execute permissions for the specified process.
The
.Dv data
parameter must point to the integer variable, where one of the
parameter must point to an integer variable, where one of the
following values is written:
.Bl -tag -width PROC_WX_MAPPINGS_DISALLOW_EXEC
.Bl -tag -width Ds
.It Dv PROC_WX_MAPPINGS_PERMIT
Creation of simultaneously writable and executable mapping is permitted,
otherwise the process cannot create such mappings.
Creation of simultaneously writable and executable mappings are permitted;
otherwise, the process cannot create such mappings.
.It Dv PROC_WX_MAPPINGS_DISALLOW_EXEC
After
.Xr execve 2 ,
the new address space should disallow creation of simultaneously
the new address space will not permit creation of simultaneously
writable and executable mappings.
.El
.Pp
Additionally, if the address space of the process disallows
Additionally, if the address space of the process does not permit
creation of simultaneously writable and executable mappings and
it is guaranteed that no such mapping was created since address space
creation, the
@ -676,19 +751,18 @@ flag is set in the returned value.
AMD64 only.
Controls the Kernel Page Table Isolation (KPTI) option for the children
of the specified process.
For the command to work, the
This control is only meaningful if KPTI has been enabled globally by the
.Va vm.pmap.kpti
tunable must be enabled on boot.
tunable.
It is not possible to change the KPTI setting for a running process,
except at the
.Xr execve 2 ,
where the address space is reinitialized.
only for new address spaces constructed by a future
.Xr execve 2 .
.Pp
The
.Fa data
parameter must point to an integer variable containing one of the
following commands:
.Bl -tag -width PROC_KPTI_CTL_DISABLE_ON_EXEC
.Bl -tag -width Ds
.It Dv PROC_KPTI_CTL_ENABLE_ON_EXEC
Enable KPTI after
.Xr execve 2 .
@ -697,36 +771,36 @@ Disable KPTI after
.Xr execve 2 .
Only root or a process having the
.Va PRIV_IO
privilege might use this option.
privilege can use this option.
.El
.It Dv PROC_KPTI_STATUS
Returns the current KPTI status for the specified process.
.Fa data
must point to the integer variable, which returns the
following statuses:
.Bl -tag -width PROC_KPTI_CTL_DISABLE_ON_EXEC
must point to an integer variable, where one of the
following values is written:
.Bl -tag -width Ds
.It Dv PROC_KPTI_CTL_ENABLE_ON_EXEC
.It Dv PROC_KPTI_CTL_DISABLE_ON_EXEC
.El
.Pp
The status is or-ed with the
The status is or-ed with
.Va PROC_KPTI_STATUS_ACTIVE
in case KPTI is active for the current address space of the process.
if KPTI is active for the current address space of the process.
.El
.Sh NOTES
Disabling tracing on a process should not be considered a security
feature, as it is bypassable both by the kernel and privileged processes,
feature, as it is bypassable both by the kernel and privileged processes
and via other system mechanisms.
As such, it should not be utilized to reliably protect cryptographic
keying material or other confidential data.
.Pp
Note that processes can trivially bypass the 'no simultaneously
writable and executable mappings' policy by first marking some mapping
as writeable and write code to it, then removing write and adding
as writeable, writing code to it, then removing write and adding
execute permission.
This may be legitimately required by some programs, such as JIT compilers.
This may be legitimately required by some programs such as JIT compilers.
.Sh RETURN VALUES
If an error occurs, a value of -1 is returned and
If an error occurs, a value of \-1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
@ -782,22 +856,21 @@ An invalid or zero signal number was requested for a
.Dv PROC_REAP_KILL
request.
.It Bq Er EINVAL
The
A
.Dv PROC_REAP_RELEASE
request was issued by the
.Xr init 8
process.
.It Bq Er EBUSY
The
A
.Dv PROC_REAP_ACQUIRE
request was issued by a process that had already acquired reaper status
and has not yet released it.
request was issued by a process that is already a reaper process.
.It Bq Er EBUSY
The
A
.Dv PROC_TRACE_CTL
request was issued for a process already being traced.
request was issued for a process being traced.
.It Bq Er EPERM
The
A
.Dv PROC_TRACE_CTL
request to re-enable tracing of the process
.Po Dv PROC_TRACE_CTL_ENABLE Pc ,
@ -805,7 +878,7 @@ or to disable persistence of
.Dv PROC_TRACE_CTL_DISABLE
on
.Xr execve 2
was issued for a non-current process.
specified a target process other than the calling process.
.It Bq Er EINVAL
The value of the integer
.Fa data
@ -826,6 +899,7 @@ or invalid signal number.
.El
.Sh SEE ALSO
.Xr dtrace 1 ,
.Xr elfctl 1 ,
.Xr proccontrol 1 ,
.Xr protect 1 ,
.Xr cap_enter 2 ,
@ -844,15 +918,17 @@ The
function appeared in
.Fx 10.0 .
.Pp
The reaper facility is based on a similar feature of Linux and
The reaper facility is based on a similar feature in Linux and
DragonflyBSD, and first appeared in
.Fx 10.2 .
.Pp
The
.Dv PROC_PDEATHSIG_CTL
facility is based on the prctl(PR_SET_PDEATHSIG, ...) feature of Linux,
facility is based on the
.Ql prctl(PR_SET_PDEATHSIG, ...)
feature in Linux,
and first appeared in
.Fx 11.2 .
.Pp
The ASLR support was added to system for the checklists compliance in
ASLR support was added for checklist compliance in
.Fx 13.0 .