Vulnerability CVE-2023-52451

Vulnerability CVE-2023-52451

Published: 2024-02-22

Description:

In the Linux kernel, the following vulnerability has been resolved:

powerpc/pseries/memhp: Fix access beyond end of drmem array

dlpar_memory_remove_by_index() may access beyond the bounds of the
drmem lmb array when the LMB lookup fails to match an entry with the
given DRC index. When the search fails, the cursor is left pointing to
&drmem_info->lmbs[drmem_info->n_lmbs], which is one element past the
last valid entry in the array. The debug message at the end of the
function then dereferences this pointer:

pr_debug("Failed to hot-remove memory at %llx\n",
lmb->base_addr);

This was found by inspection and confirmed with KASAN:

pseries-hotplug-mem: Attempting to hot-remove LMB, drc index 1234
==================================================================
BUG: KASAN: slab-out-of-bounds in dlpar_memory+0x298/0x1658
Read of size 8 at addr c000000364e97fd0 by task bash/949

dump_stack_lvl+0xa4/0xfc (unreliable)
print_report+0x214/0x63c
kasan_report+0x140/0x2e0
__asan_load8+0xa8/0xe0
dlpar_memory+0x298/0x1658
handle_dlpar_errorlog+0x130/0x1d0
dlpar_store+0x18c/0x3e0
kobj_attr_store+0x68/0xa0
sysfs_kf_write+0xc4/0x110
kernfs_fop_write_iter+0x26c/0x390
vfs_write+0x2d4/0x4e0
ksys_write+0xac/0x1a0
system_call_exception+0x268/0x530
system_call_vectored_common+0x15c/0x2ec

Allocated by task 1:
kasan_save_stack+0x48/0x80
kasan_set_track+0x34/0x50
kasan_save_alloc_info+0x34/0x50
__kasan_kmalloc+0xd0/0x120
__kmalloc+0x8c/0x320
kmalloc_array.constprop.0+0x48/0x5c
drmem_init+0x2a0/0x41c
do_one_initcall+0xe0/0x5c0
kernel_init_freeable+0x4ec/0x5a0
kernel_init+0x30/0x1e0
ret_from_kernel_user_thread+0x14/0x1c

The buggy address belongs to the object at c000000364e80000
which belongs to the cache kmalloc-128k of size 131072
The buggy address is located 0 bytes to the right of
allocated 98256-byte region [c000000364e80000, c000000364e97fd0)

==================================================================
pseries-hotplug-mem: Failed to hot-remove memory at 0

Log failed lookups with a separate message and dereference the
cursor only when it points to a valid entry.

References:

https://git.kernel.org/stable/c/bb79613a9a704469ddb8d6c6029d532a5cea384c

https://git.kernel.org/stable/c/9b5f03500bc5b083c0df696d7dd169d7ef3dd0c7

https://git.kernel.org/stable/c/b582aa1f66411d4adcc1aa55b8c575683fb4687e

https://git.kernel.org/stable/c/999a27b3ce9a69d54ccd5db000ec3a447bc43e6d

https://git.kernel.org/stable/c/026fd977dc50ff4a5e09bfb0603557f104d3f3a0

https://git.kernel.org/stable/c/df16afba2378d985359812c865a15c05c70a967e

https://git.kernel.org/stable/c/708a4b59baad96c4718dc0bd3a3427d3ab22fedc

https://git.kernel.org/stable/c/bd68ffce69f6cf8ddd3a3c32549d1d2275e49fc5

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