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Hi! |
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On Sat, Sep 09, 2017 at 11:23:46AM +0200, "Tóth Attila" wrote: |
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> I don't use docker myself, but if we are speaking about |
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> CONFIG_GRKERNSEC_PROC_USER and CONFIG_GRKERNSEC_PROC_USERGROUP, it would |
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> be important to know what GID is specified in CONFIG_GRKERNSEC_PROC_GID? |
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It's 3 (group "sys"). :) |
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# zgrep GRKERNSEC_PROC_GID /proc/config.gz |
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CONFIG_GRKERNSEC_PROC_GID=3 |
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> So if you can figure out the important |
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> process's GID, you can officially circumwent the restrictions. Too bad if |
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> the incriminated process runs as root... If you can influence with what |
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> GID the important process starts, you have a key for a solution. |
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It's a docker's "root", it has fewer capabilities than real root. |
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But, anyway, docker's "root" has mostly same groups (including "sys") as |
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host root: |
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|
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$ docker run -it --rm alpine id |
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uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),11(floppy),20(dialout),26(tape),27(video) |
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$ sudo id |
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uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),11(floppy),26(tape),27(video) |
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Looks like being in group 3(sys) within container just doesn't have same |
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effect as on host. Maybe it's because of some capabilities dropped from |
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container's root account by docker? |
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|
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-- |
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WBR, Alex. |
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