[PATCH] mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag

[PATCH] mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag

[Mark Seaborn]

I puzzled over mprotect()'s effect on /proc/*/maps for a while
yesterday -- it was setting "x" without PROT_EXEC being specified.
Here is a patch to add some explanation.

mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag

diff --git a/man2/mprotect.2 b/man2/mprotect.2
index d7b9712..a5aa2fb 100644
--- a/man2/mprotect.2
+++ b/man2/mprotect.2
@@ -125,7 +125,15 @@ Whether
 .B PROT_EXEC
 has any effect different from
 .B PROT_READ
-is architecture- and kernel version-dependent.
+depends on processor architecture, kernel version, and process state. If
+.B READ_IMPLIES_EXEC
+is set in the process's personality flags (see
+.BR personality (2)),
+specifying
+.B PROT_READ
+will implicitly add
+.BR PROT_EXEC.
+
 On some hardware architectures (e.g., i386),
 .B PROT_WRITE
 implies
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Re: [PATCH] mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag

[Michael Kerrisk (man-pages)]

On 04/23/2010 06:31 PM, Mark Seaborn wrote:
> I puzzled over mprotect()'s effect on /proc/*/maps for a while
> yesterday -- it was setting "x" without PROT_EXEC being specified.
> Here is a patch to add some explanation.

Long after the fact... But applied now. Thanks, Mark.

Cheers,

Michael


> mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag
> 
> diff --git a/man2/mprotect.2 b/man2/mprotect.2
> index d7b9712..a5aa2fb 100644
> --- a/man2/mprotect.2
> +++ b/man2/mprotect.2
> @@ -125,7 +125,15 @@ Whether
>  .B PROT_EXEC
>  has any effect different from
>  .B PROT_READ
> -is architecture- and kernel version-dependent.
> +depends on processor architecture, kernel version, and process state. If
> +.B READ_IMPLIES_EXEC
> +is set in the process's personality flags (see
> +.BR personality (2)),
> +specifying
> +.B PROT_READ
> +will implicitly add
> +.BR PROT_EXEC.
> +
>  On some hardware architectures (e.g., i386),
>  .B PROT_WRITE
>  implies
> 


-- 
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] mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag

[Michael Kerrisk (man-pages)]

On 04/23/2010 06:31 PM, Mark Seaborn wrote:
> I puzzled over mprotect()'s effect on /proc/*/maps for a while
> yesterday -- it was setting "x" without PROT_EXEC being specified.
> Here is a patch to add some explanation.

Mark, patch applied (rather late,,,).

Cheers,

Michael


> mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag
> 
> diff --git a/man2/mprotect.2 b/man2/mprotect.2
> index d7b9712..a5aa2fb 100644
> --- a/man2/mprotect.2
> +++ b/man2/mprotect.2
> @@ -125,7 +125,15 @@ Whether
>  .B PROT_EXEC
>  has any effect different from
>  .B PROT_READ
> -is architecture- and kernel version-dependent.
> +depends on processor architecture, kernel version, and process state. If
> +.B READ_IMPLIES_EXEC
> +is set in the process's personality flags (see
> +.BR personality (2)),
> +specifying
> +.B PROT_READ
> +will implicitly add
> +.BR PROT_EXEC.
> +
>  On some hardware architectures (e.g., i386),
>  .B PROT_WRITE
>  implies
> 


-- 
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] mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag

[Mark Seaborn]

On 5 February 2015 at 03:28, Michael Kerrisk (man-pages)
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On 04/23/2010 06:31 PM, Mark Seaborn wrote:
> > I puzzled over mprotect()'s effect on /proc/*/maps for a while
> > yesterday -- it was setting "x" without PROT_EXEC being specified.
> > Here is a patch to add some explanation.
>
> Long after the fact... But applied now. Thanks, Mark.

Wow, thanks!  What Git branch did you apply the fix on?  I looked at
http://git.kernel.org/cgit/docs/man-pages/man-pages.git/tree/man2/mprotect.2,
but I didn't see the change there.

Cheers,
Mark
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Re: [PATCH] mprotect(2): mention effect of READ_IMPLIES_EXEC personality flag

[Michael Kerrisk (man-pages)]

On 7 February 2015 at 03:02, Mark Seaborn <mseaborn-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
> On 5 February 2015 at 03:28, Michael Kerrisk (man-pages)
> <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> On 04/23/2010 06:31 PM, Mark Seaborn wrote:
>> > I puzzled over mprotect()'s effect on /proc/*/maps for a while
>> > yesterday -- it was setting "x" without PROT_EXEC being specified.
>> > Here is a patch to add some explanation.
>>
>> Long after the fact... But applied now. Thanks, Mark.
>
> Wow, thanks!  What Git branch did you apply the fix on?  I looked at
> http://git.kernel.org/cgit/docs/man-pages/man-pages.git/tree/man2/mprotect.2,
> but I didn't see the change there.

Not yet pushed to k.org, but you'll get a mail when the release goes out.

Thanks,

Michael

-- 
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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