From: Guenter Roeck <linux@roeck-us.net>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH] Convert filldir[64]() from __put_user() to unsafe_put_user()
Date: Sun, 6 Oct 2019 19:30:16 -0700 [thread overview]
Message-ID: <c3e9ec03-5eb5-75bb-98da-63eaa9246cff@roeck-us.net> (raw)
In-Reply-To: <CAHk-=whAQWEMADgxb_qAw=nEY4OnuDn6HU4UCSDMNT5ULKvg3g@mail.gmail.com>
On 10/6/19 6:17 PM, Linus Torvalds wrote:
> On Sun, Oct 6, 2019 at 5:04 PM Guenter Roeck <linux@roeck-us.net> wrote:
[ ... ]
> And yes, I'll fix that name copy loop in filldir to align the
> destination first, *but* if I'm right, it means that something like
> this should also likely cause issues:
>
> #define _GNU_SOURCE
> #include <unistd.h>
> #include <sys/mman.h>
>
> int main(int argc, char **argv)
> {
> void *mymap;
> uid_t *bad_ptr = (void *) 0x01;
>
> /* Create unpopulated memory area */
> mymap = mmap(NULL, 16384, PROT_READ | PROT_WRITE, MAP_PRIVATE
> | MAP_ANONYMOUS, -1, 0);
>
> /* Unaligned uidpointer in that memory area */
> bad_ptr = mymap+1;
>
> /* Make the kernel do put_user() on it */
> return getresuid(bad_ptr, bad_ptr+1, bad_ptr+2);
> }
>
> because that simple user mode program should cause that same "page
> fault on unaligned put_user()" behavior as far as I can tell.
>
> Mind humoring me and trying that on your alpha machine (or emulator,
> or whatever)?
>
Here you are. This is with v5.4-rc2 and your previous patch applied
on top.
/ # ./mmtest
Unable to handle kernel paging request at virtual address 0000000000000004
mmtest(75): Oops -1
pc = [<0000000000000004>] ra = [<fffffc0000311584>] ps = 0000 Not tainted
pc is at 0x4
ra is at entSys+0xa4/0xc0
v0 = fffffffffffffff2 t0 = 0000000000000000 t1 = 0000000000000000
t2 = 0000000000000000 t3 = 0000000000000000 t4 = 0000000000000000
t5 = 000000000000fffe t6 = 0000000000000000 t7 = fffffc0007edc000
s0 = 0000000000000000 s1 = 00000001200006f0 s2 = 00000001200df19f
s3 = 00000001200ea0b9 s4 = 0000000120114630 s5 = 00000001201145d8
s6 = 000000011f955c50
a0 = 000002000002c001 a1 = 000002000002c005 a2 = 000002000002c009
a3 = 0000000000000000 a4 = ffffffffffffffff a5 = 0000000000000000
t8 = 0000000000000000 t9 = fffffc0000000000 t10= 0000000000000000
t11= 000000011f955788 pv = fffffc0000349450 at = 00000000f8db54d3
gp = fffffc0000f2a160 sp = 00000000ab237c72
Disabling lock debugging due to kernel taint
Trace:
Code:
00000000
00063301
000007b6
00001111
00003f8d
Segmentation fault
Guenter
next prev parent reply other threads:[~2019-10-07 2:30 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-06 22:20 [PATCH] Convert filldir[64]() from __put_user() to unsafe_put_user() Guenter Roeck
2019-10-06 23:06 ` Linus Torvalds
2019-10-06 23:35 ` Linus Torvalds
2019-10-07 0:04 ` Guenter Roeck
2019-10-07 1:17 ` Linus Torvalds
2019-10-07 1:24 ` Al Viro
2019-10-07 2:06 ` Linus Torvalds
2019-10-07 2:50 ` Al Viro
2019-10-07 3:11 ` Linus Torvalds
2019-10-07 15:40 ` David Laight
2019-10-07 18:11 ` Linus Torvalds
2019-10-08 9:58 ` David Laight
2019-10-07 17:34 ` Al Viro
2019-10-07 18:13 ` Linus Torvalds
2019-10-07 18:22 ` Al Viro
2019-10-07 18:26 ` Linus Torvalds
2019-10-07 18:36 ` Tony Luck
2019-10-07 19:08 ` Linus Torvalds
2019-10-07 19:49 ` Tony Luck
2019-10-07 20:04 ` Linus Torvalds
2019-10-08 3:29 ` Al Viro
2019-10-08 4:09 ` Linus Torvalds
2019-10-08 4:14 ` Linus Torvalds
2019-10-08 5:02 ` Al Viro
2019-10-08 4:24 ` Linus Torvalds
2019-10-10 19:55 ` Al Viro
2019-10-10 22:12 ` Linus Torvalds
2019-10-11 0:11 ` Al Viro
2019-10-11 0:31 ` Linus Torvalds
2019-10-13 18:13 ` Al Viro
2019-10-13 18:43 ` Linus Torvalds
2019-10-13 19:10 ` Al Viro
2019-10-13 19:22 ` Linus Torvalds
2019-10-13 19:59 ` Al Viro
2019-10-13 20:20 ` Linus Torvalds
2019-10-15 3:46 ` Michael Ellerman
2019-10-15 18:08 ` Al Viro
2019-10-15 19:00 ` Linus Torvalds
2019-10-15 19:40 ` Al Viro
2019-10-15 20:18 ` Al Viro
2019-10-16 12:12 ` [RFC] change of calling conventions for arch_futex_atomic_op_inuser() Al Viro
2019-10-16 12:24 ` Thomas Gleixner
2019-10-16 20:25 ` [PATCH] Convert filldir[64]() from __put_user() to unsafe_put_user() Al Viro
2019-10-17 19:36 ` [RFC][PATCHES] drivers/scsi/sg.c uaccess cleanups/fixes Al Viro
2019-10-17 19:39 ` [RFC PATCH 1/8] sg_ioctl(): fix copyout handling Al Viro
2019-10-17 19:39 ` [RFC PATCH 2/8] sg_new_write(): replace access_ok() + __copy_from_user() with copy_from_user() Al Viro
2019-10-17 19:39 ` [RFC PATCH 3/8] sg_write(): __get_user() can fail Al Viro
2019-10-17 19:39 ` [RFC PATCH 4/8] sg_read(): simplify reading ->pack_id of userland sg_io_hdr_t Al Viro
2019-10-17 19:39 ` [RFC PATCH 5/8] sg_new_write(): don't bother with access_ok Al Viro
2019-10-17 19:39 ` [RFC PATCH 6/8] sg_read(): get rid of access_ok()/__copy_..._user() Al Viro
2019-10-17 19:39 ` [RFC PATCH 7/8] sg_write(): get rid of access_ok()/__copy_from_user()/__get_user() Al Viro
2019-10-17 19:39 ` [RFC PATCH 8/8] SG_IO: get rid of access_ok() Al Viro
2019-10-17 21:44 ` [RFC][PATCHES] drivers/scsi/sg.c uaccess cleanups/fixes Douglas Gilbert
2019-11-05 4:54 ` Martin K. Petersen
2019-11-05 5:25 ` Al Viro
2019-11-06 4:29 ` Martin K. Petersen
2019-10-18 0:27 ` [RFC] csum_and_copy_from_user() semantics Al Viro
2019-10-25 14:01 ` [PATCH] Convert filldir[64]() from __put_user() to unsafe_put_user() Thomas Gleixner
2019-10-08 4:57 ` Al Viro
2019-10-08 13:14 ` Greg KH
2019-10-08 15:29 ` Al Viro
2019-10-08 15:38 ` Greg KH
2019-10-08 17:06 ` Al Viro
2019-10-08 19:58 ` Al Viro
2019-10-08 20:16 ` Al Viro
2019-10-08 20:34 ` Al Viro
2019-10-07 2:30 ` Guenter Roeck [this message]
2019-10-07 3:12 ` Linus Torvalds
2019-10-07 0:23 ` Guenter Roeck
2019-10-07 4:04 ` Max Filippov
2019-10-07 12:16 ` Guenter Roeck
2019-10-07 19:21 ` Linus Torvalds
2019-10-07 20:29 ` Guenter Roeck
2019-10-07 23:27 ` Guenter Roeck
2019-10-08 6:28 ` Geert Uytterhoeven
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