btrfs: don't use btrfs_set_item_key_safe on RAID stripe-extents

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

btrfs: don't use btrfs_set_item_key_safe on RAID stripe-extents

Don't use btrfs_set_item_key_safe() to modify the keys in the RAID

stripe-tree, as this can lead to corruption of the tree, which is caught

by the checks in btrfs_set_item_key_safe():

BTRFS info (device nvme1n1): leaf 49168384 gen 15 total ptrs 194 free space 8329 owner 12

BTRFS info (device nvme1n1): refs 2 lock_owner 1030 current 1030

[ snip ]

item 105 key (354549760 230 20480) itemoff 14587 itemsize 16

stride 0 devid 5 physical 67502080

item 106 key (354631680 230 4096) itemoff 14571 itemsize 16

stride 0 devid 1 physical 88559616

item 107 key (354631680 230 32768) itemoff 14555 itemsize 16

stride 0 devid 1 physical 88555520

item 108 key (354717696 230 28672) itemoff 14539 itemsize 16

stride 0 devid 2 physical 67604480

[ snip ]

BTRFS critical (device nvme1n1): slot 106 key (354631680 230 32768) new key (354635776 230 4096)

------------[ cut here ]------------

kernel BUG at fs/btrfs/ctree.c:2602!

Oops: invalid opcode: 0000 [#1] PREEMPT SMP PTI

CPU: 1 UID: 0 PID: 1055 Comm: fsstress Not tainted 6.13.0-rc1+ #1464

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014

RIP: 0010:btrfs_set_item_key_safe+0xf7/0x270

Code: <snip>

RSP: 0018:ffffc90001337ab0 EFLAGS: 00010287

RAX: 0000000000000000 RBX: ffff8881115fd000 RCX: 0000000000000000

RDX: 0000000000000001 RSI: 0000000000000001 RDI: 00000000ffffffff

RBP: ffff888110ed6f50 R08: 00000000ffffefff R09: ffffffff8244c500

R10: 00000000ffffefff R11: 00000000ffffffff R12: ffff888100586000

R13: 00000000000000c9 R14: ffffc90001337b1f R15: ffff888110f23b58

FS: 00007f7d75c72740(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007fa811652c60 CR3: 0000000111398001 CR4: 0000000000370eb0

Call Trace:

<TASK>

? __die_body.cold+0x14/0x1a

? die+0x2e/0x50

? do_trap+0xca/0x110

? do_error_trap+0x65/0x80

? btrfs_set_item_key_safe+0xf7/0x270

? exc_invalid_op+0x50/0x70

? btrfs_set_item_key_safe+0xf7/0x270

? asm_exc_invalid_op+0x1a/0x20

? btrfs_set_item_key_safe+0xf7/0x270

btrfs_partially_delete_raid_extent+0xc4/0xe0

btrfs_delete_raid_extent+0x227/0x240

__btrfs_free_extent.isra.0+0x57f/0x9c0

? exc_coproc_segment_overrun+0x40/0x40

__btrfs_run_delayed_refs+0x2fa/0xe80

btrfs_run_delayed_refs+0x81/0xe0

btrfs_commit_transaction+0x2dd/0xbe0

? preempt_count_add+0x52/0xb0

btrfs_sync_file+0x375/0x4c0

do_fsync+0x39/0x70

__x64_sys_fsync+0x13/0x20

do_syscall_64+0x54/0x110

entry_SYSCALL_64_after_hwframe+0x76/0x7e

RIP: 0033:0x7f7d7550ef90

Code: <snip>

RSP: 002b:00007ffd70237248 EFLAGS: 00000202 ORIG_RAX: 000000000000004a

RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f7d7550ef90

RDX: 000000000000013a RSI: 000000000040eb28 RDI: 0000000000000004

RBP: 000000000000001b R08: 0000000000000078 R09: 00007ffd7023725c

R10: 00007f7d75400390 R11: 0000000000000202 R12: 028f5c28f5c28f5c

R13: 8f5c28f5c28f5c29 R14: 000000000040b520 R15: 00007f7d75c726c8

</TASK>

While the root cause of the tree order corruption isn't clear, using

btrfs_duplicate_item() to copy the item and then adjusting both the key

and the per-device physical addresses is a safe way to counter this

problem.