CVE-2024-35907

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

mlxbf_gige: call request_irq() after NAPI initialized

The mlxbf_gige driver encounters a NULL pointer exception in mlxbf_gige_open() when kdump is enabled. The sequence to reproduce the exception is as follows: a) enable kdump b) trigger kdump via echo c > /proc/sysrq-trigger c) kdump kernel executes d) kdump kernel loads mlxbf_gige module e) the mlxbf_gige module runs its open() as the the oob_net0 interface is brought up f) mlxbf_gige module will experience an exception during its open(), something like:

 Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
 Mem abort info:
   ESR = 0x0000000086000004
   EC = 0x21: IABT (current EL), IL = 32 bits
   SET = 0, FnV = 0
   EA = 0, S1PTW = 0
   FSC = 0x04: level 0 translation fault
 user pgtable: 4k pages, 48-bit VAs, pgdp=00000000e29a4000
 [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
 Internal error: Oops: 0000000086000004 [#1] SMP
 CPU: 0 PID: 812 Comm: NetworkManager Tainted: G           OE     5.15.0-1035-bluefield #37-Ubuntu
 Hardware name: https://www.mellanox.com BlueField-3 SmartNIC Main Card/BlueField-3 SmartNIC Main Card, BIOS 4.6.0.13024 Jan 19 2024
 pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : 0x0
 lr : __napi_poll+0x40/0x230
 sp : ffff800008003e00
 x29: ffff800008003e00 x28: 0000000000000000 x27: 00000000ffffffff
 x26: ffff000066027238 x25: ffff00007cedec00 x24: ffff800008003ec8
 x23: 000000000000012c x22: ffff800008003eb7 x21: 0000000000000000
 x20: 0000000000000001 x19: ffff000066027238 x18: 0000000000000000
 x17: ffff578fcb450000 x16: ffffa870b083c7c0 x15: 0000aaab010441d0
 x14: 0000000000000001 x13: 00726f7272655f65 x12: 6769675f6662786c
 x11: 0000000000000000 x10: 0000000000000000 x9 : ffffa870b0842398
 x8 : 0000000000000004 x7 : fe5a48b9069706ea x6 : 17fdb11fc84ae0d2
 x5 : d94a82549d594f35 x4 : 0000000000000000 x3 : 0000000000400100
 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000066027238
 Call trace:
  0x0
  net_rx_action+0x178/0x360
  __do_softirq+0x15c/0x428
  __irq_exit_rcu+0xac/0xec
  irq_exit+0x18/0x2c
  handle_domain_irq+0x6c/0xa0
  gic_handle_irq+0xec/0x1b0
  call_on_irq_stack+0x20/0x2c
  do_interrupt_handler+0x5c/0x70
  el1_interrupt+0x30/0x50
  el1h_64_irq_handler+0x18/0x2c
  el1h_64_irq+0x7c/0x80
  __setup_irq+0x4c0/0x950
  request_threaded_irq+0xf4/0x1bc
  mlxbf_gige_request_irqs+0x68/0x110 [mlxbf_gige]
  mlxbf_gige_open+0x5c/0x170 [mlxbf_gige]
  __dev_open+0x100/0x220
  __dev_change_flags+0x16c/0x1f0
  dev_change_flags+0x2c/0x70
  do_setlink+0x220/0xa40
  __rtnl_newlink+0x56c/0x8a0
  rtnl_newlink+0x58/0x84
  rtnetlink_rcv_msg+0x138/0x3c4
  netlink_rcv_skb+0x64/0x130
  rtnetlink_rcv+0x20/0x30
  netlink_unicast+0x2ec/0x360
  netlink_sendmsg+0x278/0x490
  __sock_sendmsg+0x5c/0x6c
  ____sys_sendmsg+0x290/0x2d4
  ___sys_sendmsg+0x84/0xd0
  __sys_sendmsg+0x70/0xd0
  __arm64_sys_sendmsg+0x2c/0x40
  invoke_syscall+0x78/0x100
  el0_svc_common.constprop.0+0x54/0x184
  do_el0_svc+0x30/0xac
  el0_svc+0x48/0x160
  el0t_64_sync_handler+0xa4/0x12c
  el0t_64_sync+0x1a4/0x1a8
 Code: bad PC value
 ---[ end trace 7d1c3f3bf9d81885 ]---
 Kernel panic - not syncing: Oops: Fatal exception in interrupt
 Kernel Offset: 0x2870a7a00000 from 0xffff800008000000
 PHYS_OFFSET: 0x80000000
 CPU features: 0x0,000005c1,a3332a5a
 Memory Limit: none
 ---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---

The exception happens because there is a pending RX interrupt before the call to request_irq(RX IRQ) executes. Then, the RX IRQ handler fires immediately after this request_irq() completes. The —truncated—

Weakness

The product dereferences a pointer that it expects to be valid but is NULL.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/24444af5ddf729376b90db0f135fa19973cb5dab
• https://git.kernel.org/stable/c/867a2f598af6a645c865d1101b58c5e070c6dd9e
• https://git.kernel.org/stable/c/8feb1652afe9c5d019059a55c90f70690dce0f52
• https://git.kernel.org/stable/c/a583117668ddb86e98f2e11c7caa3db0e6df52a3
• https://git.kernel.org/stable/c/f7442a634ac06b953fc1f7418f307b25acd4cfbc
• https://git.kernel.org/stable/c/24444af5ddf729376b90db0f135fa19973cb5dab
• https://git.kernel.org/stable/c/867a2f598af6a645c865d1101b58c5e070c6dd9e
• https://git.kernel.org/stable/c/8feb1652afe9c5d019059a55c90f70690dce0f52
• https://git.kernel.org/stable/c/a583117668ddb86e98f2e11c7caa3db0e6df52a3
• https://git.kernel.org/stable/c/f7442a634ac06b953fc1f7418f307b25acd4cfbc