Messages in this thread | | | Date | Tue, 13 Apr 2004 16:11:35 -0700 | From | Chris Wright <> | Subject | Re: [PATCH 2.6.5-mm4] sys_access race fix |
| |
* Fabian Frederick (Fabian.Frederick@skynet.be) wrote: > Well, the only major function behind user_walk is path_lookup. > This one has some calls with the nameidata.Other process seems > current->fs->xxx relevant read-only.Maybe you mean the > read_lock(¤t->fs->lock) which could bring a deadlock as we > task->lock before ?
No, point is simply that there's implicit permission check in __user_walk().
> If user_walk had to run in ruid, why would we have permission() then ?
It's how the standards require the call to be implemented. The access(2) check verifies access to the pathname using the ruid not euid. Part of valid access includes search access on the directory elements of the full pathname. Those tests are done during __user_walk.
thanks, -chris -- Linux Security Modules http://lsm.immunix.org http://lsm.bkbits.net - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |