Messages in this thread | | | From | Alexey Dobriyan <> | Date | Tue, 28 Nov 2017 12:12:44 +0200 | Subject | Re: proc: fix /proc/*/map_files lookup |
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On 11/28/17, Andrei Vagin <avagin@virtuozzo.com> wrote: > On Tue, Nov 21, 2017 at 12:27:06AM +0300, Alexey Dobriyan wrote: >> Current code does: >> >> if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2) >> >> However sscanf() is broken garbage. >> >> It silently accepts whitespace between format specifiers >> (did you know that?). >> >> It silently accepts valid strings which result in integer overflow. >> >> Do not use sscanf() for any even remotely reliable parsing code. > > This patch breaks criu, criu has one places where a file name is generated > as map_files/%p-%p
> openat(1048572, "map_files/0x7f9912dd5000-0x7f9912de4000", O_RDWR) = -1
glibc prints null pointer as "(nil)", so %p is broken even if lookup is fixed.
> And this code worked before this patch and it doesn't work with this > patch. And you have to know that we never break user-space programs ;)
OK :-)
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