CVE-2024-26983: bootconfig: use memblock_free_late to free xbc memory to buddy
Description
In the Linux kernel, the following vulnerability has been resolved:
bootconfig: use memblock_free_late to free xbc memory to buddy
On the time to free xbc memory in xbc_exit(), memblock may has handed
over memory to buddy allocator. So it doesn't make sense to free memory
back to memblock. memblock_free() called by xbc_exit() even causes UAF bugs
on architectures with CONFIG_ARCH_KEEP_MEMBLOCK disabled like x86.
Following KASAN logs shows this case.
This patch fixes the xbc memory free problem by calling memblock_free()
in early xbc init error rewind path and calling memblock_free_late() in
xbc exit path to free memory to buddy allocator.
[ 9.410890] ==================================================================
[ 9.418962] BUG: KASAN: use-after-free in memblock_isolate_range+0x12d/0x260
[ 9.426850] Read of size 8 at addr ffff88845dd30000 by task swapper/0/1
[ 9.435901] CPU: 9 PID: 1 Comm: swapper/0 Tainted: G U 6.9.0-rc3-00208-g586b5dfb51b9 #5
[ 9.446403] Hardware name: Intel Corporation RPLP LP5 (CPU:RaptorLake)/RPLP LP5 (ID:13), BIOS IRPPN02.01.01.00.00.19.015.D-00000000 Dec 28 2023
[ 9.460789] Call Trace:
[ 9.463518]
[ 9.465859] dump_stack_lvl+0x53/0x70
[ 9.469949] print_report+0xce/0x610
[ 9.473944] ? __virt_addr_valid+0xf5/0x1b0
[ 9.478619] ? memblock_isolate_range+0x12d/0x260
[ 9.483877] kasan_report+0xc6/0x100
[ 9.487870] ? memblock_isolate_range+0x12d/0x260
[ 9.493125] memblock_isolate_ran...
Classification
CVE ID: CVE-2024-26983
Affected Products
Vendor: Linux
Product: Linux
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.04% (probability of being exploited)
EPSS Percentile: 5.08% (scored less or equal to compared to others)
EPSS Date: 2025-02-04 (when was this score calculated)
References
https://git.kernel.org/stable/c/1e7feb31a18c197d63a5e606025ed63c762f8918https://git.kernel.org/stable/c/e46d3be714ad9652480c6db129ab8125e2d20ab7
https://git.kernel.org/stable/c/5a7dfb8fcd3f29fc93161100179b27f24f3d5f35
https://git.kernel.org/stable/c/89f9a1e876b5a7ad884918c03a46831af202c8a0