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dd issues on Ubuntu 6.10

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(@3saul)
Active Member
Joined: 19 years ago
Posts: 5
Topic starter  

I'm having difficulty dumping the memory from a Ubuntu 6.10 PC. When I try and run it (yes both using sudo and as root) I get

dd reading '/dev/mem' Operation not permitted
2056+0 records in
2056+0 records out
1.1MB copied

I've tried this on both my physical machine and a VMWare session. Can anybody shed some light?

dd if=/dev/mem bs=4096 of=/home/xxx/dd.dd


   
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Jamie
(@jamie)
Moderator
Joined: 5 years ago
Posts: 1288
 

Hi,

Could it be a patched kernel restricting access to /dev/mem perhaps (even to root)? I Googled a little and found that removing CAP_SYS_RAWIO from the capability bounding set would also (I believe) prevent root access to /dev/mem, although I'm not very familiar with the terminology.

Jamie


   
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(@fatrabbit)
Estimable Member
Joined: 21 years ago
Posts: 132
 

Jamie is right, it's a permissions thing. Check out the man page for mem for a solution to the ownership problem. The character device file may already exist so the mknod command might not be necessary, and the chown will need sudo.


   
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(@3saul)
Active Member
Joined: 19 years ago
Posts: 5
Topic starter  

Jamie, thank you. You are correct. It's a capabilities issue as opposed to a permissions issue. Getting around this without a reboot should prove interesting. I'll report my findings.


   
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Jamie
(@jamie)
Moderator
Joined: 5 years ago
Posts: 1288
 

Can't take too much credit, just a Google-inspired lucky guess…must buy a lottery ticket tomorrow lol

Good luck with it anyway, do let us know how you get on!

Cheers,

Jamie


   
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