CVE-2022-50507

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

fs/ntfs3: Validate data run offset

This adds sanity checks for data run offset. We should make sure data run offset is legit before trying to unpack them, otherwise we may encounter use-after-free or some unexpected memory access behaviors.

[ 82.940342] BUG: KASAN: use-after-free in run_unpack+0x2e3/0x570 [ 82.941180] Read of size 1 at addr ffff888008a8487f by task mount/240 [ 82.941670] [ 82.942069] CPU: 0 PID: 240 Comm: mount Not tainted 5.19.0+ #15 [ 82.942482] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 82.943720] Call Trace: [ 82.944204] [ 82.944471] dump_stack_lvl+0x49/0x63 [ 82.944908] print_report.cold+0xf5/0x67b [ 82.945141] ? __wait_on_bit+0x106/0x120 [ 82.945750] ? run_unpack+0x2e3/0x570 [ 82.946626] kasan_report+0xa7/0x120 [ 82.947046] ? run_unpack+0x2e3/0x570 [ 82.947280] __asan_load1+0x51/0x60 [ 82.947483] run_unpack+0x2e3/0x570 [ 82.947709] ? memcpy+0x4e/0x70 [ 82.947927] ? run_pack+0x7a0/0x7a0 [ 82.948158] run_unpack_ex+0xad/0x3f0 [ 82.948399] ? mi_enum_attr+0x14a/0x200 [ 82.948717] ? run_unpack+0x570/0x570 [ 82.949072] ? ni_enum_attr_ex+0x1b2/0x1c0 [ 82.949332] ? ni_fname_type.part.0+0xd0/0xd0 [ 82.949611] ? mi_read+0x262/0x2c0 [ 82.949970] ? ntfs_cmp_names_cpu+0x125/0x180 [ 82.950249] ntfs_iget5+0x632/0x1870 [ 82.950621] ? ntfs_get_block_bmap+0x70/0x70 [ 82.951192] ? evict+0x223/0x280 [ 82.951525] ? iput.part.0+0x286/0x320 [ 82.951969] ntfs_fill_super+0x1321/0x1e20 [ 82.952436] ? put_ntfs+0x1d0/0x1d0 [ 82.952822] ? vsprintf+0x20/0x20 [ 82.953188] ? mutex_unlock+0x81/0xd0 [ 82.953379] ? set_blocksize+0x95/0x150 [ 82.954001] get_tree_bdev+0x232/0x370 [ 82.954438] ? put_ntfs+0x1d0/0x1d0 [ 82.954700] ntfs_fs_get_tree+0x15/0x20 [ 82.955049] vfs_get_tree+0x4c/0x130 [ 82.955292] path_mount+0x645/0xfd0 [ 82.955615] ? putname+0x80/0xa0 [ 82.955955] ? finish_automount+0x2e0/0x2e0 [ 82.956310] ? kmem_cache_free+0x110/0x390 [ 82.956723] ? putname+0x80/0xa0 [ 82.957023] do_mount+0xd6/0xf0 [ 82.957411] ? path_mount+0xfd0/0xfd0 [ 82.957638] ? __kasan_check_write+0x14/0x20 [ 82.957948] __x64_sys_mount+0xca/0x110 [ 82.958310] do_syscall_64+0x3b/0x90 [ 82.958719] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 82.959341] RIP: 0033:0x7fd0d1ce948a [ 82.960193] Code: 48 8b 0d 11 fa 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 008 [ 82.961532] RSP: 002b:00007ffe59ff69a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5 [ 82.962527] RAX: ffffffffffffffda RBX: 0000564dcc107060 RCX: 00007fd0d1ce948a [ 82.963266] RDX: 0000564dcc107260 RSI: 0000564dcc1072e0 RDI: 0000564dcc10fce0 [ 82.963686] RBP: 0000000000000000 R08: 0000564dcc107280 R09: 0000000000000020 [ 82.964272] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 0000564dcc10fce0 [ 82.964785] R13: 0000564dcc107260 R14: 0000000000000000 R15: 00000000ffffffff

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/6db620863f8528ed9a9aa5ad323b26554a17881d
• https://git.kernel.org/stable/c/9173b89c16a603d73c434b695fe2a7a13491300f
• https://git.kernel.org/stable/c/de5e0955248ff90a2ae91e7f5c108392b52152d0
• https://git.kernel.org/stable/c/e0455361d3068066a91fe18282b751925d7b5ee7