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It should be noted that with a UID larger than INT_MAX a lot of things will start to break, ext4 for example only supports 32bit UIDs, so you won't be able to c
by zaarn 8y ago
It should be noted that with a UID larger than INT_MAX a lot of things will start to break, ext4 for example only supports 32bit UIDs, so you won't be able to chown any files as this UID (atleast my own experimentation seems to find this. NFSv4 allows it if you enable squashing/mapping of user ids).
Lots of other tools will likely break in similar and unpredictable ways if your UID becomes that high. Likely those ways are also a lot of fun.
Since you'd need to be a privileged user to begin with, this is on the same alarm level as "running sed with sudo allows you to edit /etc/sudoers and gain full sudo privilege".
- userbinator 8y agoext4 for example only supports 32bit UIDs Unsigned or signed? That seems to be the critical difference here.
- gerdesj 8y agoI'm no C programmer but these looks like hints: https://github.com/torvalds/linux/blob/master/fs/ext4/ext4.h#L689 https://github.com/torvalds/linux/blob/master/fs/ext4/ext4.h... https://github.com/torvalds/linux/blob/master/fs/ext4/ext4.h#L1105 https://github.com/torvalds/linux/blob/master/fs/ext4/ext4.h...
- opless 8y agoAccording to this[1] NIS+ Probably allows it, so there's probably a nice multi-step attack possible... [1] https://docs.oracle.com/cd/E19620-01/805-3727/userconcept-3/index.html https://docs.oracle.com/cd/E19620-01/805-3727/userconcept-3/...