[PATCH 1/3] prctl(2): PR_SET_MM: document arg4/arg5 zero behavior

[PATCH 1/3] prctl(2): PR_SET_MM: document arg4/arg5 zero behavior

[Mike Frysinger]

The kernel will immediately reject calls where arg4/arg5 are not zero.
See kernel/sys.c:prctl_set_mm().

Signed-off-by: Mike Frysinger <vapier-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
 man2/prctl.2 | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/man2/prctl.2 b/man2/prctl.2
index 97cf21a4c558..c91d328e5aa1 100644
--- a/man2/prctl.2
+++ b/man2/prctl.2
@@ -515,6 +515,11 @@ The value in
 is one of the options below, while
 .I arg3
 provides a new value for the option.
+The
+.I arg4
+and
+.I arg5
+arguments must be zero if unused.
 .RS
 .TP
 .BR PR_SET_MM_START_CODE
-- 
2.11.0

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[PATCH 2/3] prctl(2): PR_SET_MM: document new PR_SET_MM_MAP{,_SIZE} helpers

[Mike Frysinger]

Signed-off-by: Mike Frysinger <vapier-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
 man2/prctl.2 | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/man2/prctl.2 b/man2/prctl.2
index c91d328e5aa1..dba32ebee1b5 100644
--- a/man2/prctl.2
+++ b/man2/prctl.2
@@ -633,6 +633,34 @@ in a process life time.
 Any further attempts will be rejected.
 This should help system administrators monitor unusual
 symbolic-link transitions over all processes running on a system.
+.P
+The following options are available since Linux 3.18.
+.\" commit f606b77f1a9e362451aca8f81d8f36a3a112139e
+.TP
+.BR PR_SET_MM_MAP
+Provides one-shot access to all the addresses by passing in a
+.I struct prctl_mm_map
+(as defined in \fI<linux/prctl.h>\fP).
+The
+.I arg4
+argument should provide the size of the struct.
+
+This feature is available only if the kernel is built with the
+.BR CONFIG_CHECKPOINT_RESTORE
+option enabled.
+.TP
+.BR PR_SET_MM_MAP_SIZE
+Returns the size of the
+.I struct prctl_mm_map
+the kernel expects.
+This allows user space to find a compatible struct.
+The
+.I arg4
+argument should be a pointer to an unsigned int.
+
+This feature is available only if the kernel is built with the
+.BR CONFIG_CHECKPOINT_RESTORE
+option enabled.
 .RE
 .TP
 .BR PR_MPX_ENABLE_MANAGEMENT ", " PR_MPX_DISABLE_MANAGEMENT " (since Linux 3.19) "
-- 
2.11.0

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[PATCH 3/3] prctl(2): PR_SET_MM: refine CONFIG_CHECKPOINT_RESTORE requirement

[Mike Frysinger]

The Linux 3.10 release dropped the c/r requirement and opened it up
to all users.

Signed-off-by: Mike Frysinger <vapier-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
 man2/prctl.2 | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/man2/prctl.2 b/man2/prctl.2
index dba32ebee1b5..42827aa2def4 100644
--- a/man2/prctl.2
+++ b/man2/prctl.2
@@ -504,9 +504,7 @@ Usually these fields are set by the kernel and dynamic loader (see
 for more information) and a regular application should not use this feature.
 However, there are cases, such as self-modifying programs,
 where a program might find it useful to change its own memory map.
-This feature is available only if the kernel is built with the
-.BR CONFIG_CHECKPOINT_RESTORE
-option enabled.
+
 The calling process must have the
 .BR CAP_SYS_RESOURCE
 capability.
@@ -520,6 +518,14 @@ The
 and
 .I arg5
 arguments must be zero if unused.
+
+.\" commit 52b3694157e3aa6df871e283115652ec6f2d31e0
+Since Linux 3.10,
+this feature is available all the time.
+Before Linux 3.10,
+this feature is available only if the kernel is built with the
+.BR CONFIG_CHECKPOINT_RESTORE
+option enabled.
 .RS
 .TP
 .BR PR_SET_MM_START_CODE
-- 
2.11.0

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Re: [PATCH 1/3] prctl(2): PR_SET_MM: document arg4/arg5 zero behavior

[Michael Kerrisk (man-pages)]

On 02/15/2017 09:14 PM, Mike Frysinger wrote:
> The kernel will immediately reject calls where arg4/arg5 are not zero.
> See kernel/sys.c:prctl_set_mm().

Thanks, Mike. Applied.

Cheers,

Michael

> Signed-off-by: Mike Frysinger <vapier-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
>  man2/prctl.2 | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/man2/prctl.2 b/man2/prctl.2
> index 97cf21a4c558..c91d328e5aa1 100644
> --- a/man2/prctl.2
> +++ b/man2/prctl.2
> @@ -515,6 +515,11 @@ The value in
>  is one of the options below, while
>  .I arg3
>  provides a new value for the option.
> +The
> +.I arg4
> +and
> +.I arg5
> +arguments must be zero if unused.
>  .RS
>  .TP
>  .BR PR_SET_MM_START_CODE
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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Re: [PATCH 2/3] prctl(2): PR_SET_MM: document new PR_SET_MM_MAP{,_SIZE} helpers

[Michael Kerrisk (man-pages)]

On 02/15/2017 09:14 PM, Mike Frysinger wrote:
> Signed-off-by: Mike Frysinger <vapier-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

Thanks, Mike. Applied.

Cheers,

Michael


> ---
>  man2/prctl.2 | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/man2/prctl.2 b/man2/prctl.2
> index c91d328e5aa1..dba32ebee1b5 100644
> --- a/man2/prctl.2
> +++ b/man2/prctl.2
> @@ -633,6 +633,34 @@ in a process life time.
>  Any further attempts will be rejected.
>  This should help system administrators monitor unusual
>  symbolic-link transitions over all processes running on a system.
> +.P
> +The following options are available since Linux 3.18.
> +.\" commit f606b77f1a9e362451aca8f81d8f36a3a112139e
> +.TP
> +.BR PR_SET_MM_MAP
> +Provides one-shot access to all the addresses by passing in a
> +.I struct prctl_mm_map
> +(as defined in \fI<linux/prctl.h>\fP).
> +The
> +.I arg4
> +argument should provide the size of the struct.
> +
> +This feature is available only if the kernel is built with the
> +.BR CONFIG_CHECKPOINT_RESTORE
> +option enabled.
> +.TP
> +.BR PR_SET_MM_MAP_SIZE
> +Returns the size of the
> +.I struct prctl_mm_map
> +the kernel expects.
> +This allows user space to find a compatible struct.
> +The
> +.I arg4
> +argument should be a pointer to an unsigned int.
> +
> +This feature is available only if the kernel is built with the
> +.BR CONFIG_CHECKPOINT_RESTORE
> +option enabled.
>  .RE
>  .TP
>  .BR PR_MPX_ENABLE_MANAGEMENT ", " PR_MPX_DISABLE_MANAGEMENT " (since Linux 3.19) "
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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Re: [PATCH 3/3] prctl(2): PR_SET_MM: refine CONFIG_CHECKPOINT_RESTORE requirement

[Michael Kerrisk (man-pages)]

On 02/15/2017 09:14 PM, Mike Frysinger wrote:
> The Linux 3.10 release dropped the c/r requirement and opened it up
> to all users.

Thanks, Mike. Applied.

Cheers,

Michael


> Signed-off-by: Mike Frysinger <vapier-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
>  man2/prctl.2 | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/man2/prctl.2 b/man2/prctl.2
> index dba32ebee1b5..42827aa2def4 100644
> --- a/man2/prctl.2
> +++ b/man2/prctl.2
> @@ -504,9 +504,7 @@ Usually these fields are set by the kernel and dynamic loader (see
>  for more information) and a regular application should not use this feature.
>  However, there are cases, such as self-modifying programs,
>  where a program might find it useful to change its own memory map.
> -This feature is available only if the kernel is built with the
> -.BR CONFIG_CHECKPOINT_RESTORE
> -option enabled.
> +
>  The calling process must have the
>  .BR CAP_SYS_RESOURCE
>  capability.
> @@ -520,6 +518,14 @@ The
>  and
>  .I arg5
>  arguments must be zero if unused.
> +
> +.\" commit 52b3694157e3aa6df871e283115652ec6f2d31e0
> +Since Linux 3.10,
> +this feature is available all the time.
> +Before Linux 3.10,
> +this feature is available only if the kernel is built with the
> +.BR CONFIG_CHECKPOINT_RESTORE
> +option enabled.
>  .RS
>  .TP
>  .BR PR_SET_MM_START_CODE
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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