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Replies:
3
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Last Post:
Oct 29, 2008 9:10 PM
by: johnfred
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Alfred Peng
Alfred.Peng@Sun.COM
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Question on an LD option "-M mapfile"
Posted:
Jan 4, 2006 8:07 PM
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Hi there,
I'm a software engineer from the JDS browser group, and working on a
bug to add the non-execution stack function to Mozilla/Firefox.
The option "-M /usr/lib/ld/map.noexstk" has been added to the build
configuration, and the content of the file map.noexstk is "stack = STACK
?RW;". I just wonder whether there is a way for me to test the function
after building successfully?
Thanks,
-Alfred
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Posts:
295
From:
US
Registered:
3/9/05
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Re: Question on an LD option "-M mapfile"
Posted:
Jan 4, 2006 10:22 PM
in response to: Alfred Peng
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Alfred Peng wrote:
> The option "-M /usr/lib/ld/map.noexstk" has been added to the build
> configuration, and the content of the file map.noexstk is "stack = STACK
> ?RW;". I just wonder whether there is a way for me to test the function
> after building successfully?
This mapfile creates a program header that tells the kernel that
the process requires a non-executable stack. You can see this from
the read/write access, but no execute access, assigned to the
program header:
% cc -o main main.c -M/usr/lib/ld/map.noexstk
% elfdump -p main | tail -6
Program Header[5]:
p_vaddr: 0 p_flags: [ PF_W PF_R ]
p_paddr: 0 p_type: [ PT_SUNWSTACK ]
p_filesz: 0 p_memsz: 0
p_offset: 0 p_align: 0
You can use ptools on the application to verify the stacks
accessibility:
% truss -Texit ./main
.......
% pmap -x 184337
184337: ./main
Address Kbytes RSS Anon Locked Mode Mapped File
00010000 8 8 - - r-x-- main
00020000 8 8 8 - rwx-- main
........
FFBFE000 8 8 8 - rw--- [ stack ]
--
Rod
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Alfred Peng
Alfred.Peng@Sun.COM
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Re: Question on an LD option "-M mapfile"
Posted:
Jan 4, 2006 11:41 PM
in response to: rie
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Your instructions work on the Firefox build I've got. And the
non-execution stack function has been enabled in Firefox.
Thanks,
-Alfred
Rod Evans wrote:
> Alfred Peng wrote:
>
>
>> The option "-M /usr/lib/ld/map.noexstk" has been added to the build
>> configuration, and the content of the file map.noexstk is "stack = STACK
>> ?RW;". I just wonder whether there is a way for me to test the function
>> after building successfully?
>>
>
> This mapfile creates a program header that tells the kernel that
> the process requires a non-executable stack. You can see this from
> the read/write access, but no execute access, assigned to the
> program header:
>
> % cc -o main main.c -M/usr/lib/ld/map.noexstk
> % elfdump -p main | tail -6
>
> Program Header[5]:
> p_vaddr: 0 p_flags: [ PF_W PF_R ]
> p_paddr: 0 p_type: [ PT_SUNWSTACK ]
> p_filesz: 0 p_memsz: 0
> p_offset: 0 p_align: 0
>
> You can use ptools on the application to verify the stacks
> accessibility:
>
> % truss -Texit ./main
> .......
> % pmap -x 184337
> 184337: ./main
> Address Kbytes RSS Anon Locked Mode Mapped File
> 00010000 8 8 - - r-x-- main
> 00020000 8 8 8 - rwx-- main
> ........
> FFBFE000 8 8 8 - rw--- [ stack ]
>
>
>
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Posts:
1
From:
Registered:
10/29/08
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Re: Question on an LD option "-M mapfile"
Posted:
Oct 29, 2008 9:10 PM
in response to: Alfred Peng
To: Communities » tools » linking
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This website is very useful software engineers like me also.We can clarify our doubts about solaris in here.Thanks to this website.
================================
john
Link Building
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