diff options
| author | Kefeng Wang <wangkefeng.wang@huawei.com> | 2024-03-02 14:43:12 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-03-06 13:04:18 -0800 |
| commit | 5aa598a72eafcf05239519646ec88638c8894dba (patch) | |
| tree | 126f460637fa42dc205dc2f83c6513930a2576c1 /mm | |
| parent | 57b77b75caf02c7f1784ba5f9ea55275bd9a27b4 (diff) | |
mm: memory: fix shift-out-of-bounds in fault_around_bytes_set
The rounddown_pow_of_two(0) is undefined, so val = 0 is not allowed in the
fault_around_bytes_set(), and leads to shift-out-of-bounds,
UBSAN: shift-out-of-bounds in include/linux/log2.h:67:13
shift exponent 4294967295 is too large for 64-bit type 'long unsigned int'
CPU: 7 PID: 107 Comm: sh Not tainted 6.8.0-rc6-next-20240301 #294
Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
Call trace:
dump_backtrace+0x94/0xec
show_stack+0x18/0x24
dump_stack_lvl+0x78/0x90
dump_stack+0x18/0x24
ubsan_epilogue+0x10/0x44
__ubsan_handle_shift_out_of_bounds+0x98/0x134
fault_around_bytes_set+0xa4/0xb0
simple_attr_write_xsigned.isra.0+0xe4/0x1ac
simple_attr_write+0x18/0x24
debugfs_attr_write+0x4c/0x98
vfs_write+0xd0/0x4b0
ksys_write+0x6c/0xfc
__arm64_sys_write+0x1c/0x28
invoke_syscall+0x44/0x104
el0_svc_common.constprop.0+0x40/0xe0
do_el0_svc+0x1c/0x28
el0_svc+0x34/0xdc
el0t_64_sync_handler+0xc0/0xc4
el0t_64_sync+0x190/0x194
---[ end trace ]---
Fix it by setting the minimum val to PAGE_SIZE.
Link: https://lkml.kernel.org/r/20240302064312.2358924-1-wangkefeng.wang@huawei.com
Fixes: 53d36a56d8c4 ("mm: prefer fault_around_pages to fault_around_bytes")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: Yue Sun <samsun1006219@gmail.com>
Closes: https://lore.kernel.org/all/CAEkJfYPim6DQqW1GqCiHLdh2-eweqk1fGyXqs3JM+8e1qGge8w@mail.gmail.com/
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c index abd4f33d62c9..e17669d4f72f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4776,7 +4776,8 @@ static int fault_around_bytes_set(void *data, u64 val) * The minimum value is 1 page, however this results in no fault-around * at all. See should_fault_around(). */ - fault_around_pages = max(rounddown_pow_of_two(val) >> PAGE_SHIFT, 1UL); + val = max(val, PAGE_SIZE); + fault_around_pages = rounddown_pow_of_two(val) >> PAGE_SHIFT; return 0; } |