CVE-2025-21725

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

smb: client: fix oops due to unset link speed

It isn't guaranteed that NETWORK_INTERFACE_INFO::LinkSpeed will always

be set by the server, so the client must handle any values and then

prevent oopses like below from happening:

Oops: divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI

CPU: 0 UID: 0 PID: 1323 Comm: cat Not tainted 6.13.0-rc7 #2

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-3.fc41

04/01/2014

RIP: 0010:cifs_debug_data_proc_show+0xa45/0x1460 [cifs] Code: 00 00 48

89 df e8 3b cd 1b c1 41 f6 44 24 2c 04 0f 84 50 01 00 00 48 89 ef e8

e7 d0 1b c1 49 8b 44 24 18 31 d2 49 8d 7c 24 28 <48> f7 74 24 18 48 89

c3 e8 6e cf 1b c1 41 8b 6c 24 28 49 8d 7c 24

RSP: 0018:ffffc90001817be0 EFLAGS: 00010246

RAX: 0000000000000000 RBX: ffff88811230022c RCX: ffffffffc041bd99

RDX: 0000000000000000 RSI: 0000000000000567 RDI: ffff888112300228

RBP: ffff888112300218 R08: fffff52000302f5f R09: ffffed1022fa58ac

R10: ffff888117d2c566 R11: 00000000fffffffe R12: ffff888112300200

R13: 000000012a15343f R14: 0000000000000001 R15: ffff888113f2db58

FS: 00007fe27119e740(0000) GS:ffff888148600000(0000)

knlGS:0000000000000000

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

CR2: 00007fe2633c5000 CR3: 0000000124da0000 CR4: 0000000000750ef0

PKRU: 55555554

Call Trace:

<TASK>

? __die_body.cold+0x19/0x27

? die+0x2e/0x50

? do_trap+0x159/0x1b0

? cifs_debug_data_proc_show+0xa45/0x1460 [cifs]

? do_error_trap+0x90/0x130

? cifs_debug_data_proc_show+0xa45/0x1460 [cifs]

? exc_divide_error+0x39/0x50

? cifs_debug_data_proc_show+0xa45/0x1460 [cifs]

? asm_exc_divide_error+0x1a/0x20

? cifs_debug_data_proc_show+0xa39/0x1460 [cifs]

? cifs_debug_data_proc_show+0xa45/0x1460 [cifs]

? seq_read_iter+0x42e/0x790

seq_read_iter+0x19a/0x790

proc_reg_read_iter+0xbe/0x110

? __pfx_proc_reg_read_iter+0x10/0x10

vfs_read+0x469/0x570

? do_user_addr_fault+0x398/0x760

? __pfx_vfs_read+0x10/0x10

? find_held_lock+0x8a/0xa0

? __pfx_lock_release+0x10/0x10

ksys_read+0xd3/0x170

? __pfx_ksys_read+0x10/0x10

? __rcu_read_unlock+0x50/0x270

? mark_held_locks+0x1a/0x90

do_syscall_64+0xbb/0x1d0

entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7fe271288911

Code: 00 48 8b 15 01 25 10 00 f7 d8 64 89 02 b8 ff ff ff ff eb bd e8

20 ad 01 00 f3 0f 1e fa 80 3d b5 a7 10 00 00 74 13 31 c0 0f 05 <48> 3d

00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec

RSP: 002b:00007ffe87c079d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000

RAX: ffffffffffffffda RBX: 0000000000040000 RCX: 00007fe271288911

RDX: 0000000000040000 RSI: 00007fe2633c6000 RDI: 0000000000000003

RBP: 00007ffe87c07a00 R08: 0000000000000000 R09: 00007fe2713e6380

R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000040000

R13: 00007fe2633c6000 R14: 0000000000000003 R15: 0000000000000000

</TASK>

Fix this by setting cifs_server_iface::speed to a sane value (1Gbps)

by default when link speed is unset.