Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [PATCH] Added PR_SET_PROCTITLE_AREA option for prctl() | Date | Mon, 5 Oct 2009 16:18:58 +0900 (JST) |
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> On Sun, Oct 4, 2009 at 11:29 PM, KOSAKI Motohiro > <kosaki.motohiro@jp.fujitsu.com> wrote: > >> On Sun, Oct 4, 2009 at 10:48 PM, KOSAKI Motohiro > >> <kosaki.motohiro@jp.fujitsu.com> wrote: > >> > >> > + } else { > >> > + len = mm->env_end - mm->env_start; > >> > + if (len > PAGE_SIZE - res) > >> > + len = PAGE_SIZE - res; > >> > + res += access_process_vm(task, mm->env_start, > >> > + buffer+res, len, 0); > >> > + res = strnlen(buffer, res); > >> > + } > >> > >> > >> This bug was in the original code, but since you're touching it > >> anyway, it should be fixed now; if this access_process_vm fails > >> (perhaps due to the target unmapping the page in question in between > >> the two calls), bad things might happen if (error code) + res < 0, as > >> then strnlen will get a huge value in its length (possibly leading to > >> OOPS etc). It should be changed to check for an error return here and > >> fail out properly if there is an error in this second check. > > > > AFAIK, access_process_vm() never return negative value. > > Ahh, okay, I had read the if (res > 0 && ...) bit in the original code > as an error test. Nevermind then.
No problem. very thak you for your good reviewing :)
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