Commit ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and hugetlb_infinity")
replaced
'unsigned long hugetlb_zero' with 'int zero' leading to out-of-bounds access
in proc_doulongvec_minmax():
==================================================================
BUG: AddressSanitizer: out of bounds access in
__do_proc_doulongvec_minmax+0x8a0/0x9a0 at addr ffffffff83980960
Read of size 8 by task trinity-c14/6919
Out-of-bounds access to the global variable 'zero'
[ffffffff83980960-ffffffff83980964) defined at ipc/ipc_sysctl.c:158
CPU: 1 PID: 6919 Comm: trinity-c14 Not tainted 3.18.0-rc1+ #50
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
0000000000000001 ffff8800b68cf418 ffffffff82c2d3ae 0000000000000000
ffff8800b68cf4c0 ffff8800b68cf4a8 ffffffff813eaa81 ffffffff0000000c
ffff88010b003600 ffff8800b68cf479 0000000000000296 0000000000000000
Call Trace:
[<ffffffff813ead71>] __asan_report_load8_noabort+0x51/0x70
mm/kasan/report.c:248
[<ffffffff810cc3e0>] __do_proc_doulongvec_minmax+0x8a0/0x9a0
kernel/sysctl.c:2284
[< inlined >] proc_doulongvec_minmax+0x50/0x80
do_proc_doulongvec_minmax kernel/sysctl.c:2322
[<ffffffff810cc530>] proc_doulongvec_minmax+0x50/0x80
kernel/sysctl.c:2345
[<ffffffff813c9e5a>] hugetlb_sysctl_handler_common+0x12a/0x3c0
mm/hugetlb.c:2270
[<ffffffff813cb45c>] hugetlb_mempolicy_sysctl_handler+0x1c/0x20
mm/hugetlb.c:2293
[<ffffffff8153e6e9>] proc_sys_call_handler+0x179/0x1f0
fs/proc/proc_sysctl.c:506
[<ffffffff8153e76f>] proc_sys_write+0xf/0x20 fs/proc/proc_sysctl.c:524
[<ffffffff813f1563>] __kernel_write+0x123/0x440 fs/read_write.c:502
[<ffffffff8147ebaa>] write_pipe_buf+0x14a/0x1d0 fs/splice.c:1074
[< inlined >] __splice_from_pipe+0x22e/0x6f0
splice_from_pipe_feed fs/splice.c:769
[<ffffffff8147dbde>] __splice_from_pipe+0x22e/0x6f0 fs/splice.c:886
[<ffffffff81483211>] splice_from_pipe+0xc1/0x110 fs/splice.c:921
[<ffffffff81483298>] default_file_splice_write+0x18/0x50
fs/splice.c:1086
[< inlined >] direct_splice_actor+0x104/0x1c0 do_splice_from
fs/splice.c:1128
[<ffffffff8147cfc4>] direct_splice_actor+0x104/0x1c0 fs/splice.c:1284
[<ffffffff8147e5ba>] splice_direct_to_actor+0x24a/0x6f0
fs/splice.c:1237
[<ffffffff81483424>] do_splice_direct+0x154/0x270 fs/splice.c:1327
[<ffffffff813f3bfb>] do_sendfile+0x5fb/0x1260 fs/read_write.c:1266
[< inlined >] SyS_sendfile64+0xfa/0x100 SYSC_sendfile64
fs/read_write.c:1327
[<ffffffff813f6bea>] SyS_sendfile64+0xfa/0x100 fs/read_write.c:1313
[<ffffffff82c464f9>] ia32_do_call+0x13/0x13
arch/x86/ia32/ia32entry.S:444
Memory state around the buggy address:
ffffffff83980680: 04 f8 f8 f8 f8 f8 f8 f8 02 f8 f8 f8 f8 f8 f8 f8
ffffffff83980700: 00 f8 f8 f8 f8 f8 f8 f8 00 f8 f8 f8 f8 f8 f8 f8
ffffffff83980780: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 00 00 00 00
ffffffff83980800: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 04 f8 f8 f8
ffffffff83980880: f8 f8 f8 f8 04 f8 f8 f8 f8 f8 f8 f8 04 f8 f8 f8
>ffffffff83980900: f8 f8 f8 f8 04 f8 f8 f8 f8 f8 f8 f8 04 f8 f8 f8
^
ffffffff83980980: f8 f8 f8 f8 00 00 00 00 f8 f8 f8 f8 00 00 00 00
ffffffff83980a00: 02 f8 f8 f8 f8 f8 f8 f8 00 00 00 00 00 00 00 00
ffffffff83980a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffff83980b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffff83980b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
Use the 'unsigned long' type for 'zero' variable to fix this.
Changing type to 'unsigned long' shouldn't affect any other users
of this variable.
Reported-by: Dmitry Vyukov <dvyu...@google.com>
Fixes: ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and hugetlb_infinity")
Signed-off-by: Andrey Ryabinin <a.ryabi...@samsung.com>
---
kernel/sysctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 15f2511..45c45c9 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -120,7 +120,7 @@ static int sixty = 60;
static int __maybe_unused neg_one = -1;
-static int zero;
+static unsigned long zero;
static int __maybe_unused one = 1;
static int __maybe_unused two = 2;
static int __maybe_unused four = 4;
--
2.2.0
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