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Kefeng Wang deab81144d powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit
[ Upstream commit ffa0b64e3be58519ae472ea29a1a1ad681e32f48 ]

mpe: On 64-bit Book3E vmalloc space starts at 0x8000000000000000.

Because of the way __pa() works we have:
  __pa(0x8000000000000000) == 0, and therefore
  virt_to_pfn(0x8000000000000000) == 0, and therefore
  virt_addr_valid(0x8000000000000000) == true

Which is wrong, virt_addr_valid() should be false for vmalloc space.
In fact all vmalloc addresses that alias with a valid PFN will return
true from virt_addr_valid(). That can cause bugs with hardened usercopy
as described below by Kefeng Wang:

  When running ethtool eth0 on 64-bit Book3E, a BUG occurred:

    usercopy: Kernel memory exposure attempt detected from SLUB object not in SLUB page?! (offset 0, size 1048)!
    kernel BUG at mm/usercopy.c:99
    ...
    usercopy_abort+0x64/0xa0 (unreliable)
    __check_heap_object+0x168/0x190
    __check_object_size+0x1a0/0x200
    dev_ethtool+0x2494/0x2b20
    dev_ioctl+0x5d0/0x770
    sock_do_ioctl+0xf0/0x1d0
    sock_ioctl+0x3ec/0x5a0
    __se_sys_ioctl+0xf0/0x160
    system_call_exception+0xfc/0x1f0
    system_call_common+0xf8/0x200

  The code shows below,

    data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));
    copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))

  The data is alloced by vmalloc(), virt_addr_valid(ptr) will return true
  on 64-bit Book3E, which leads to the panic.

  As commit 4dd7554a64 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va
  and __pa addresses") does, make sure the virt addr above PAGE_OFFSET in
  the virt_addr_valid() for 64-bit, also add upper limit check to make
  sure the virt is below high_memory.

  Meanwhile, for 32-bit PAGE_OFFSET is the virtual address of the start
  of lowmem, high_memory is the upper low virtual address, the check is
  suitable for 32-bit, this will fix the issue mentioned in commit
  602946ec2f90 ("powerpc: Set max_mapnr correctly") too.

On 32-bit there is a similar problem with high memory, that was fixed in
commit 602946ec2f90 ("powerpc: Set max_mapnr correctly"), but that
commit breaks highmem and needs to be reverted.

We can't easily fix __pa(), we have code that relies on its current
behaviour. So for now add extra checks to virt_addr_valid().

For 64-bit Book3S the extra checks are not necessary, the combination of
virt_to_pfn() and pfn_valid() should yield the correct result, but they
are harmless.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Add additional change log detail]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220406145802.538416-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-20 09:19:37 +02:00
arch powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit 2022-04-20 09:19:37 +02:00
block Revert "Revert "block, bfq: honor already-setup queue merges"" 2022-04-15 14:18:23 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: authenc - Fix sleep in atomic context in decrypt_tail 2022-04-15 14:18:04 +02:00
Documentation dt-bindings: spi: mxic: The interrupt property is not mandatory 2022-04-15 14:18:30 +02:00
drivers drm/amd/display: Fix allocate_mst_payload assert on resume 2022-04-20 09:19:37 +02:00
fs cifs: potential buffer overflow in handling symlinks 2022-04-20 09:19:36 +02:00
include tlb: hugetlb: Add more sizes to tlb_remove_huge_tlb_entry 2022-04-20 09:19:37 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-15 14:18:35 +02:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel cgroup: Use open-time cgroup namespace for process migration perm checks 2022-04-15 14:18:41 +02:00
lib lz4: fix LZ4_decompress_safe_partial read out of bound 2022-04-15 14:18:39 +02:00
LICENSES
mm mm: don't skip swap entry even if zap_details specified 2022-04-15 14:18:40 +02:00
net nfc: nci: add flush_workqueue to prevent uaf 2022-04-20 09:19:35 +02:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts gcc-plugins/stackleak: Exactly match strings instead of prefixes 2022-04-15 14:18:22 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-15 14:18:22 +02:00
sound ASoC: topology: Allow TLV control to be either read or write 2022-04-15 14:18:30 +02:00
tools testing/selftests/mqueue: Fix mq_perf_tests to free the allocated cpu set 2022-04-20 09:19:35 +02:00
usr
virt KVM: Prevent module exit until all VMs are freed 2022-04-15 14:18:27 +02:00
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Makefile Linux 5.4.189 2022-04-15 14:18:42 +02:00
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