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freebsd-src/lib/libsys/mprotect.2

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BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.\" Copyright (c) 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
Renumber copyright clause 4 Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00
.\" 3. Neither the name of the University nor the names of its contributors
BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
mprotect.2: Improve the description of prot The new wording for standard flags is losely based on the POSIX description. Make it clearer that PROT_MAX() is a local extension. Reviewed by: alc, mckusick, imp, kib, markj Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D31777
2021-09-07 16:28:50 +00:00
.Dd September 7, 2021
BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.Dt MPROTECT 2
.Os
.Sh NAME
.Nm mprotect
.Nd control the protection of pages
Introduce ".Lb" macro to libc manpages. More libraries manpages updates following.
2000-04-21 09:42:15 +00:00
.Sh LIBRARY
.Lb libc
BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.Sh SYNOPSIS
mdoc(7) police: Use the new .In macro for #include statements.
2001-10-01 16:09:29 +00:00
.In sys/mman.h
Add RETURN VALUES and ERRORS sections.
1997-01-11 23:20:29 +00:00
.Ft int
mprotect(): Change prototype to comply to POSIX. Our mprotect() function seems to take a "const void *" address to the pages whose permissions need to be adjusted. POSIX uses "void *". Simply stick to the POSIX one to prevent us from writing unportable code. PR: 211423 (exp-run) Tested by: antoine@ (Thanks!)
2016-08-03 06:33:04 +00:00
.Fn mprotect "void *addr" "size_t len" "int prot"
BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.Sh DESCRIPTION
The
.Fn mprotect
system call
changes the specified pages to have protection
.Fa prot .
Document protection bits. PR: 46252 Submitted by: Jeroen Ruigrok van der Werven <asmodai@wxs.nl>
2002-12-23 19:25:03 +00:00
.Pp
mprotect.2: Improve the description of prot The new wording for standard flags is losely based on the POSIX description. Make it clearer that PROT_MAX() is a local extension. Reviewed by: alc, mckusick, imp, kib, markj Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D31777
2021-09-07 16:28:50 +00:00
The
.Fa prot
argument shall be
.Dv PROT_NONE
(no permissions at all)
or the bitwise
.Em or
of one or more of the following values:
mdoc(7) police: markup laundry.
2003-02-23 01:47:49 +00:00
.Pp
.Bl -tag -width ".Dv PROT_WRITE" -compact
.It Dv PROT_READ
Document protection bits. PR: 46252 Submitted by: Jeroen Ruigrok van der Werven <asmodai@wxs.nl>
2002-12-23 19:25:03 +00:00
The pages can be read.
mdoc(7) police: markup laundry.
2003-02-23 01:47:49 +00:00
.It Dv PROT_WRITE
Document protection bits. PR: 46252 Submitted by: Jeroen Ruigrok van der Werven <asmodai@wxs.nl>
2002-12-23 19:25:03 +00:00
The pages can be written.
mdoc(7) police: markup laundry.
2003-02-23 01:47:49 +00:00
.It Dv PROT_EXEC
Document protection bits. PR: 46252 Submitted by: Jeroen Ruigrok van der Werven <asmodai@wxs.nl>
2002-12-23 19:25:03 +00:00
The pages can be executed.
.El
Extend mmap/mprotect API to specify the max page protections. A new macro PROT_MAX() alters a protection value so it can be OR'd with a regular protection value to specify the maximum permissions. If present, these flags specify the maximum permissions. While these flags are non-portable, they can be used in portable code with simple ifdefs to expand PROT_MAX() to 0. This change allows (e.g.) a region that must be writable during run-time linking or JIT code generation to be made permanently read+execute after writes are complete. This complements W^X protections allowing more precise control by the programmer. This change alters mprotect argument checking and returns an error when unhandled protection flags are set. This differs from POSIX (in that POSIX only specifies an error), but is the documented behavior on Linux and more closely matches historical mmap behavior. In addition to explicit setting of the maximum permissions, an experimental sysctl vm.imply_prot_max causes mmap to assume that the initial permissions requested should be the maximum when the sysctl is set to 1. PROT_NONE mappings are excluded from this for compatibility with rtld and other consumers that use such mappings to reserve address space before mapping contents into part of the reservation. A final version this is expected to provide per-binary and per-process opt-in/out options and this sysctl will go away in its current form. As such it is undocumented. Reviewed by: emaste, kib (prior version), markj Additional suggestions from: alc Obtained from: CheriBSD Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D18880
2019-06-20 18:24:16 +00:00
.Pp
mprotect.2: Improve the description of prot The new wording for standard flags is losely based on the POSIX description. Make it clearer that PROT_MAX() is a local extension. Reviewed by: alc, mckusick, imp, kib, markj Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D31777
2021-09-07 16:28:50 +00:00
In addition to these standard protection flags,
the
Extend mmap/mprotect API to specify the max page protections. A new macro PROT_MAX() alters a protection value so it can be OR'd with a regular protection value to specify the maximum permissions. If present, these flags specify the maximum permissions. While these flags are non-portable, they can be used in portable code with simple ifdefs to expand PROT_MAX() to 0. This change allows (e.g.) a region that must be writable during run-time linking or JIT code generation to be made permanently read+execute after writes are complete. This complements W^X protections allowing more precise control by the programmer. This change alters mprotect argument checking and returns an error when unhandled protection flags are set. This differs from POSIX (in that POSIX only specifies an error), but is the documented behavior on Linux and more closely matches historical mmap behavior. In addition to explicit setting of the maximum permissions, an experimental sysctl vm.imply_prot_max causes mmap to assume that the initial permissions requested should be the maximum when the sysctl is set to 1. PROT_NONE mappings are excluded from this for compatibility with rtld and other consumers that use such mappings to reserve address space before mapping contents into part of the reservation. A final version this is expected to provide per-binary and per-process opt-in/out options and this sysctl will go away in its current form. As such it is undocumented. Reviewed by: emaste, kib (prior version), markj Additional suggestions from: alc Obtained from: CheriBSD Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D18880
2019-06-20 18:24:16 +00:00
.Fx
mprotect.2: Improve the description of prot The new wording for standard flags is losely based on the POSIX description. Make it clearer that PROT_MAX() is a local extension. Reviewed by: alc, mckusick, imp, kib, markj Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D31777
2021-09-07 16:28:50 +00:00
implementation of
.Fn mprotect
Extend mmap/mprotect API to specify the max page protections. A new macro PROT_MAX() alters a protection value so it can be OR'd with a regular protection value to specify the maximum permissions. If present, these flags specify the maximum permissions. While these flags are non-portable, they can be used in portable code with simple ifdefs to expand PROT_MAX() to 0. This change allows (e.g.) a region that must be writable during run-time linking or JIT code generation to be made permanently read+execute after writes are complete. This complements W^X protections allowing more precise control by the programmer. This change alters mprotect argument checking and returns an error when unhandled protection flags are set. This differs from POSIX (in that POSIX only specifies an error), but is the documented behavior on Linux and more closely matches historical mmap behavior. In addition to explicit setting of the maximum permissions, an experimental sysctl vm.imply_prot_max causes mmap to assume that the initial permissions requested should be the maximum when the sysctl is set to 1. PROT_NONE mappings are excluded from this for compatibility with rtld and other consumers that use such mappings to reserve address space before mapping contents into part of the reservation. A final version this is expected to provide per-binary and per-process opt-in/out options and this sysctl will go away in its current form. As such it is undocumented. Reviewed by: emaste, kib (prior version), markj Additional suggestions from: alc Obtained from: CheriBSD Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D18880
2019-06-20 18:24:16 +00:00
provides the ability to set the maximum protection of a region
(which prevents
.Nm
mprotect.2: Improve the description of prot The new wording for standard flags is losely based on the POSIX description. Make it clearer that PROT_MAX() is a local extension. Reviewed by: alc, mckusick, imp, kib, markj Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D31777
2021-09-07 16:28:50 +00:00
from adding to the permissions later).
This is accomplished by bitwise
Extend mmap/mprotect API to specify the max page protections. A new macro PROT_MAX() alters a protection value so it can be OR'd with a regular protection value to specify the maximum permissions. If present, these flags specify the maximum permissions. While these flags are non-portable, they can be used in portable code with simple ifdefs to expand PROT_MAX() to 0. This change allows (e.g.) a region that must be writable during run-time linking or JIT code generation to be made permanently read+execute after writes are complete. This complements W^X protections allowing more precise control by the programmer. This change alters mprotect argument checking and returns an error when unhandled protection flags are set. This differs from POSIX (in that POSIX only specifies an error), but is the documented behavior on Linux and more closely matches historical mmap behavior. In addition to explicit setting of the maximum permissions, an experimental sysctl vm.imply_prot_max causes mmap to assume that the initial permissions requested should be the maximum when the sysctl is set to 1. PROT_NONE mappings are excluded from this for compatibility with rtld and other consumers that use such mappings to reserve address space before mapping contents into part of the reservation. A final version this is expected to provide per-binary and per-process opt-in/out options and this sysctl will go away in its current form. As such it is undocumented. Reviewed by: emaste, kib (prior version), markj Additional suggestions from: alc Obtained from: CheriBSD Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D18880
2019-06-20 18:24:16 +00:00
.Em or Ns 'ing
one or more
.Dv PROT_
values wrapped in the
.Dv PROT_MAX()
macro into the
.Fa prot
argument.
Add RETURN VALUES and ERRORS sections.
1997-01-11 23:20:29 +00:00
.Sh RETURN VALUES
Use the ``.Rv -std'' mdoc(7) macro in appropriate cases. Reviewed by: ru
2001-08-09 13:32:13 +00:00
.Rv -std mprotect
Add RETURN VALUES and ERRORS sections.
1997-01-11 23:20:29 +00:00
.Sh ERRORS
The
.Fn mprotect
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe.
2002-12-18 09:22:32 +00:00
system call will fail if:
Add RETURN VALUES and ERRORS sections.
1997-01-11 23:20:29 +00:00
.Bl -tag -width Er
mprotect.2: sort errors alphabetically Reported by: brooks MFC after: 3 days
2020-02-26 18:46:41 +00:00
.It Bq Er EACCES
The calling process was not allowed to change
the protection to the value specified by
the
.Fa prot
argument.
Add RETURN VALUES and ERRORS sections.
1997-01-11 23:20:29 +00:00
.It Bq Er EINVAL
The virtual address range specified by the
.Fa addr
and
.Fa len
arguments is not valid.
Extend mmap/mprotect API to specify the max page protections. A new macro PROT_MAX() alters a protection value so it can be OR'd with a regular protection value to specify the maximum permissions. If present, these flags specify the maximum permissions. While these flags are non-portable, they can be used in portable code with simple ifdefs to expand PROT_MAX() to 0. This change allows (e.g.) a region that must be writable during run-time linking or JIT code generation to be made permanently read+execute after writes are complete. This complements W^X protections allowing more precise control by the programmer. This change alters mprotect argument checking and returns an error when unhandled protection flags are set. This differs from POSIX (in that POSIX only specifies an error), but is the documented behavior on Linux and more closely matches historical mmap behavior. In addition to explicit setting of the maximum permissions, an experimental sysctl vm.imply_prot_max causes mmap to assume that the initial permissions requested should be the maximum when the sysctl is set to 1. PROT_NONE mappings are excluded from this for compatibility with rtld and other consumers that use such mappings to reserve address space before mapping contents into part of the reservation. A final version this is expected to provide per-binary and per-process opt-in/out options and this sysctl will go away in its current form. As such it is undocumented. Reviewed by: emaste, kib (prior version), markj Additional suggestions from: alc Obtained from: CheriBSD Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D18880
2019-06-20 18:24:16 +00:00
.It Bq Er EINVAL
The
.Fa prot
argument contains unhandled bits.
Return ENOTSUP for mmap/mprotect if prot not subset of prot_max From POSIX, [ENOTSUP] The implementation does not support the combination of accesses requested in the prot argument. This fits the case that prot contains permissions which are not a subset of prot_max. Reviewed by: brooks, cem Relnotes: Yes Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D23843
2020-02-26 20:03:43 +00:00
.It Bq Er ENOTSUP
Extend mmap/mprotect API to specify the max page protections. A new macro PROT_MAX() alters a protection value so it can be OR'd with a regular protection value to specify the maximum permissions. If present, these flags specify the maximum permissions. While these flags are non-portable, they can be used in portable code with simple ifdefs to expand PROT_MAX() to 0. This change allows (e.g.) a region that must be writable during run-time linking or JIT code generation to be made permanently read+execute after writes are complete. This complements W^X protections allowing more precise control by the programmer. This change alters mprotect argument checking and returns an error when unhandled protection flags are set. This differs from POSIX (in that POSIX only specifies an error), but is the documented behavior on Linux and more closely matches historical mmap behavior. In addition to explicit setting of the maximum permissions, an experimental sysctl vm.imply_prot_max causes mmap to assume that the initial permissions requested should be the maximum when the sysctl is set to 1. PROT_NONE mappings are excluded from this for compatibility with rtld and other consumers that use such mappings to reserve address space before mapping contents into part of the reservation. A final version this is expected to provide per-binary and per-process opt-in/out options and this sysctl will go away in its current form. As such it is undocumented. Reviewed by: emaste, kib (prior version), markj Additional suggestions from: alc Obtained from: CheriBSD Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D18880
2019-06-20 18:24:16 +00:00
The
.Fa prot
argument contains permissions which are not a subset of the specified
maximum permissions.
Forgot a .El macro.
1997-01-11 23:26:44 +00:00
.El
BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.Sh SEE ALSO
.Xr madvise 2 ,
Add RETURN VALUES and ERRORS sections.
1997-01-11 23:20:29 +00:00
.Xr mincore 2 ,
.Xr msync 2 ,
.Xr munmap 2
BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.Sh HISTORY
The
.Fn mprotect
Add PROT_MAX to the HISTORY section. In the case of mmap(), add a HISTORY section. Mention that mmap() and mprotect()'s documentation predates an implementation. The implementation first saw wide use in 4.3-Reno, but there seems to be no easy way to express that in mdoc so stick with 4.4BSD. Reviewed by: emaste Requested by: cem Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D20713
2019-06-20 21:52:30 +00:00
system call was first documented in
.Bx 4.2
and first appeared in
Correctly use .Fn instead of .Nm to reference function names in a bunch of man pages. Use the correct .Bx (BSD UNIX) or .At (AT&T UNIX) macros instead of explicitly specifying the version in the text in a bunch of man pages.
1996-08-22 23:31:07 +00:00
.Bx 4.4 .
Add PROT_MAX to the HISTORY section. In the case of mmap(), add a HISTORY section. Mention that mmap() and mprotect()'s documentation predates an implementation. The implementation first saw wide use in 4.3-Reno, but there seems to be no easy way to express that in mdoc so stick with 4.4BSD. Reviewed by: emaste Requested by: cem Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D20713
2019-06-20 21:52:30 +00:00
.Pp
The
.Dv PROT_MAX
functionality was introduced in
.Fx 13 .
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