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rust: remove Arc from the kernel crate. #470

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Merged
merged 1 commit into from
Oct 14, 2021

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@wedsonaf wedsonaf commented Jul 31, 2021

These references existed to support binder, but are no longer needed.

Signed-off-by: Wedson Almeida Filho [email protected]

These references existed to support binder, but are no longer needed.

Signed-off-by: Wedson Almeida Filho <[email protected]>
@wedsonaf wedsonaf merged commit a99d5ab into Rust-for-Linux:rust Oct 14, 2021
@wedsonaf wedsonaf deleted the kernel-arc branch October 14, 2021 17:14
ojeda pushed a commit that referenced this pull request Dec 9, 2024
Jordy says:

"
In the xsk_map_delete_elem function an unsigned integer
(map->max_entries) is compared with a user-controlled signed integer
(k). Due to implicit type conversion, a large unsigned value for
map->max_entries can bypass the intended bounds check:

	if (k >= map->max_entries)
		return -EINVAL;

This allows k to hold a negative value (between -2147483648 and -2),
which is then used as an array index in m->xsk_map[k], which results
in an out-of-bounds access.

	spin_lock_bh(&m->lock);
	map_entry = &m->xsk_map[k]; // Out-of-bounds map_entry
	old_xs = unrcu_pointer(xchg(map_entry, NULL));  // Oob write
	if (old_xs)
		xsk_map_sock_delete(old_xs, map_entry);
	spin_unlock_bh(&m->lock);

The xchg operation can then be used to cause an out-of-bounds write.
Moreover, the invalid map_entry passed to xsk_map_sock_delete can lead
to further memory corruption.
"

It indeed results in following splat:

[76612.897343] BUG: unable to handle page fault for address: ffffc8fc2e461108
[76612.904330] #PF: supervisor write access in kernel mode
[76612.909639] #PF: error_code(0x0002) - not-present page
[76612.914855] PGD 0 P4D 0
[76612.917431] Oops: Oops: 0002 [#1] PREEMPT SMP
[76612.921859] CPU: 11 UID: 0 PID: 10318 Comm: a.out Not tainted 6.12.0-rc1+ #470
[76612.929189] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[76612.939781] RIP: 0010:xsk_map_delete_elem+0x2d/0x60
[76612.944738] Code: 00 00 41 54 55 53 48 63 2e 3b 6f 24 73 38 4c 8d a7 f8 00 00 00 48 89 fb 4c 89 e7 e8 2d bf 05 00 48 8d b4 eb 00 01 00 00 31 ff <48> 87 3e 48 85 ff 74 05 e8 16 ff ff ff 4c 89 e7 e8 3e bc 05 00 31
[76612.963774] RSP: 0018:ffffc9002e407df8 EFLAGS: 00010246
[76612.969079] RAX: 0000000000000000 RBX: ffffc9002e461000 RCX: 0000000000000000
[76612.976323] RDX: 0000000000000001 RSI: ffffc8fc2e461108 RDI: 0000000000000000
[76612.983569] RBP: ffffffff80000001 R08: 0000000000000000 R09: 0000000000000007
[76612.990812] R10: ffffc9002e407e18 R11: ffff888108a38858 R12: ffffc9002e4610f8
[76612.998060] R13: ffff888108a38858 R14: 00007ffd1ae0ac78 R15: ffffc9002e4610c0
[76613.005303] FS:  00007f80b6f59740(0000) GS:ffff8897e0ec0000(0000) knlGS:0000000000000000
[76613.013517] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[76613.019349] CR2: ffffc8fc2e461108 CR3: 000000011e3ef001 CR4: 00000000007726f0
[76613.026595] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[76613.033841] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[76613.041086] PKRU: 55555554
[76613.043842] Call Trace:
[76613.046331]  <TASK>
[76613.048468]  ? __die+0x20/0x60
[76613.051581]  ? page_fault_oops+0x15a/0x450
[76613.055747]  ? search_extable+0x22/0x30
[76613.059649]  ? search_bpf_extables+0x5f/0x80
[76613.063988]  ? exc_page_fault+0xa9/0x140
[76613.067975]  ? asm_exc_page_fault+0x22/0x30
[76613.072229]  ? xsk_map_delete_elem+0x2d/0x60
[76613.076573]  ? xsk_map_delete_elem+0x23/0x60
[76613.080914]  __sys_bpf+0x19b7/0x23c0
[76613.084555]  __x64_sys_bpf+0x1a/0x20
[76613.088194]  do_syscall_64+0x37/0xb0
[76613.091832]  entry_SYSCALL_64_after_hwframe+0x4b/0x53
[76613.096962] RIP: 0033:0x7f80b6d1e88d
[76613.100592] Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 b5 0f 00 f7 d8 64 89 01 48
[76613.119631] RSP: 002b:00007ffd1ae0ac68 EFLAGS: 00000206 ORIG_RAX: 0000000000000141
[76613.131330] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f80b6d1e88d
[76613.142632] RDX: 0000000000000098 RSI: 00007ffd1ae0ad20 RDI: 0000000000000003
[76613.153967] RBP: 00007ffd1ae0adc0 R08: 0000000000000000 R09: 0000000000000000
[76613.166030] R10: 00007f80b6f77040 R11: 0000000000000206 R12: 00007ffd1ae0aed8
[76613.177130] R13: 000055ddf42ce1e9 R14: 000055ddf42d0d98 R15: 00007f80b6fab040
[76613.188129]  </TASK>

Fix this by simply changing key type from int to u32.

Fixes: fbfc504 ("bpf: introduce new bpf AF_XDP map type BPF_MAP_TYPE_XSKMAP")
CC: [email protected]
Reported-by: Jordy Zomer <[email protected]>
Suggested-by: Jordy Zomer <[email protected]>
Reviewed-by: Toke Høiland-Jørgensen <[email protected]>
Acked-by: John Fastabend <[email protected]>
Signed-off-by: Maciej Fijalkowski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
Darksonn pushed a commit to Darksonn/linux that referenced this pull request Jan 17, 2025
Use is_64_bit_hypercall() instead of is_64_bit_mode() to detect a 64-bit
hypercall when completing said hypercall.  For guests with protected state,
e.g. SEV-ES and SEV-SNP, KVM must assume the hypercall was made in 64-bit
mode as the vCPU state needed to detect 64-bit mode is unavailable.

Hacking the sev_smoke_test selftest to generate a KVM_HC_MAP_GPA_RANGE
hypercall via VMGEXIT trips the WARN:

  ------------[ cut here ]------------
  WARNING: CPU: 273 PID: 326626 at arch/x86/kvm/x86.h:180 complete_hypercall_exit+0x44/0xe0 [kvm]
  Modules linked in: kvm_amd kvm ... [last unloaded: kvm]
  CPU: 273 UID: 0 PID: 326626 Comm: sev_smoke_test Not tainted 6.12.0-smp--392e932fa0f3-feat Rust-for-Linux#470
  Hardware name: Google Astoria/astoria, BIOS 0.20240617.0-0 06/17/2024
  RIP: 0010:complete_hypercall_exit+0x44/0xe0 [kvm]
  Call Trace:
   <TASK>
   kvm_arch_vcpu_ioctl_run+0x2400/0x2720 [kvm]
   kvm_vcpu_ioctl+0x54f/0x630 [kvm]
   __se_sys_ioctl+0x6b/0xc0
   do_syscall_64+0x83/0x160
   entry_SYSCALL_64_after_hwframe+0x76/0x7e
   </TASK>
  ---[ end trace 0000000000000000 ]---

Fixes: b5aead0 ("KVM: x86: Assume a 64-bit hypercall for guests with protected state")
Cc: [email protected]
Cc: Tom Lendacky <[email protected]>
Reviewed-by: Xiaoyao Li <[email protected]>
Reviewed-by: Nikunj A Dadhania <[email protected]>
Reviewed-by: Tom Lendacky <[email protected]>
Reviewed-by: Binbin Wu <[email protected]>
Reviewed-by: Kai Huang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>
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