CVE-2024-26983

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> bootconfig: use memblock_free_late to free xbc memory to buddy<br /> <br /> On the time to free xbc memory in xbc_exit(), memblock may has handed<br /> over memory to buddy allocator. So it doesn&amp;#39;t make sense to free memory<br /> back to memblock. memblock_free() called by xbc_exit() even causes UAF bugs<br /> on architectures with CONFIG_ARCH_KEEP_MEMBLOCK disabled like x86.<br /> Following KASAN logs shows this case.<br /> <br /> This patch fixes the xbc memory free problem by calling memblock_free()<br /> in early xbc init error rewind path and calling memblock_free_late() in<br /> xbc exit path to free memory to buddy allocator.<br /> <br /> [ 9.410890] ==================================================================<br /> [ 9.418962] BUG: KASAN: use-after-free in memblock_isolate_range+0x12d/0x260<br /> [ 9.426850] Read of size 8 at addr ffff88845dd30000 by task swapper/0/1<br /> <br /> [ 9.435901] CPU: 9 PID: 1 Comm: swapper/0 Tainted: G U 6.9.0-rc3-00208-g586b5dfb51b9 #5<br /> [ 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<br /> [ 9.460789] Call Trace:<br /> [ 9.463518] <br /> [ 9.465859] dump_stack_lvl+0x53/0x70<br /> [ 9.469949] print_report+0xce/0x610<br /> [ 9.473944] ? __virt_addr_valid+0xf5/0x1b0<br /> [ 9.478619] ? memblock_isolate_range+0x12d/0x260<br /> [ 9.483877] kasan_report+0xc6/0x100<br /> [ 9.487870] ? memblock_isolate_range+0x12d/0x260<br /> [ 9.493125] memblock_isolate_range+0x12d/0x260<br /> [ 9.498187] memblock_phys_free+0xb4/0x160<br /> [ 9.502762] ? __pfx_memblock_phys_free+0x10/0x10<br /> [ 9.508021] ? mutex_unlock+0x7e/0xd0<br /> [ 9.512111] ? __pfx_mutex_unlock+0x10/0x10<br /> [ 9.516786] ? kernel_init_freeable+0x2d4/0x430<br /> [ 9.521850] ? __pfx_kernel_init+0x10/0x10<br /> [ 9.526426] xbc_exit+0x17/0x70<br /> [ 9.529935] kernel_init+0x38/0x1e0<br /> [ 9.533829] ? _raw_spin_unlock_irq+0xd/0x30<br /> [ 9.538601] ret_from_fork+0x2c/0x50<br /> [ 9.542596] ? __pfx_kernel_init+0x10/0x10<br /> [ 9.547170] ret_from_fork_asm+0x1a/0x30<br /> [ 9.551552] <br /> <br /> [ 9.555649] The buggy address belongs to the physical page:<br /> [ 9.561875] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x45dd30<br /> [ 9.570821] flags: 0x200000000000000(node=0|zone=2)<br /> [ 9.576271] page_type: 0xffffffff()<br /> [ 9.580167] raw: 0200000000000000 ffffea0011774c48 ffffea0012ba1848 0000000000000000<br /> [ 9.588823] raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000<br /> [ 9.597476] page dumped because: kasan: bad access detected<br /> <br /> [ 9.605362] Memory state around the buggy address:<br /> [ 9.610714] ffff88845dd2ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00<br /> [ 9.618786] ffff88845dd2ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00<br /> [ 9.626857] &gt;ffff88845dd30000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff<br /> [ 9.634930] ^<br /> [ 9.638534] ffff88845dd30080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff<br /> [ 9.646605] ffff88845dd30100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff<br /> [ 9.654675] ==================================================================