Subject: CVE-2024-38540: bnxt_re: avoid shift undefined behavior in bnxt_qplib_alloc_init_hwq

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

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

bnxt_re: avoid shift undefined behavior in bnxt_qplib_alloc_init_hwq

Undefined behavior is triggered when bnxt_qplib_alloc_init_hwq is called
with hwq_attr->aux_depth != 0 and hwq_attr->aux_stride == 0.
In that case, "roundup_pow_of_two(hwq_attr->aux_stride)" gets called.
roundup_pow_of_two is documented as undefined for 0.

Fix it in the one caller that had this combination.

The undefined behavior was detected by UBSAN:
  UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
  shift exponent 64 is too large for 64-bit type 'long unsigned int'
  CPU: 24 PID: 1075 Comm: (udev-worker) Not tainted 6.9.0-rc6+ #4
  Hardware name: Abacus electric, s.r.o. - [email-masked] Super Server/H12SSW-iN, BIOS 2.7 10/25/2023
  Call Trace:
   <TASK>
   dump_stack_lvl+0x5d/0x80
   ubsan_epilogue+0x5/0x30
   __ubsan_handle_shift_out_of_bounds.cold+0x61/0xec
   __roundup_pow_of_two+0x25/0x35 [bnxt_re]
   bnxt_qplib_alloc_init_hwq+0xa1/0x470 [bnxt_re]
   bnxt_qplib_create_qp+0x19e/0x840 [bnxt_re]
   bnxt_re_create_qp+0x9b1/0xcd0 [bnxt_re]
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? __kmalloc+0x1b6/0x4f0
   ? create_qp.part.0+0x128/0x1c0 [ib_core]
   ? __pfx_bnxt_re_create_qp+0x10/0x10 [bnxt_re]
   create_qp.part.0+0x128/0x1c0 [ib_core]
   ib_create_qp_kernel+0x50/0xd0 [ib_core]
   create_mad_qp+0x8e/0xe0 [ib_core]
   ? __pfx_qp_event_handler+0x10/0x10 [ib_core]
   ib_mad_init_device+0x2be/0x680 [ib_core]
   add_client_context+0x10d/0x1a0 [ib_core]
   enable_device_and_get+0xe0/0x1d0 [ib_core]
   ib_register_device+0x53c/0x630 [ib_core]
   ? srso_alias_return_thunk+0x5/0xfbef5
   bnxt_re_probe+0xbd8/0xe50 [bnxt_re]
   ? __pfx_bnxt_re_probe+0x10/0x10 [bnxt_re]
   auxiliary_bus_probe+0x49/0x80
   ? driver_sysfs_add+0x57/0xc0
   really_probe+0xde/0x340
   ? pm_runtime_barrier+0x54/0x90
   ? __pfx___driver_attach+0x10/0x10
   __driver_probe_device+0x78/0x110
   driver_probe_device+0x1f/0xa0
   __driver_attach+0xba/0x1c0
   bus_for_each_dev+0x8f/0xe0
   bus_add_driver+0x146/0x220
   driver_register+0x72/0xd0
   __auxiliary_driver_register+0x6e/0xd0
   ? __pfx_bnxt_re_mod_init+0x10/0x10 [bnxt_re]
   bnxt_re_mod_init+0x3e/0xff0 [bnxt_re]
   ? __pfx_bnxt_re_mod_init+0x10/0x10 [bnxt_re]
   do_one_initcall+0x5b/0x310
   do_init_module+0x90/0x250
   init_module_from_file+0x86/0xc0
   idempotent_init_module+0x121/0x2b0
   __x64_sys_finit_module+0x5e/0xb0
   do_syscall_64+0x82/0x160
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? syscall_exit_to_user_mode_prepare+0x149/0x170
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? syscall_exit_to_user_mode+0x75/0x230
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? do_syscall_64+0x8e/0x160
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? __count_memcg_events+0x69/0x100
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? count_memcg_events.constprop.0+0x1a/0x30
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? handle_mm_fault+0x1f0/0x300
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? do_user_addr_fault+0x34e/0x640
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? srso_alias_return_thunk+0x5/0xfbef5
   entry_SYSCALL_64_after_hwframe+0x76/0x7e
  RIP: 0033:0x7f4e5132821d
  Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 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 e3 db 0c 00 f7 d8 64 89 01 48
  RSP: 002b:00007ffca9c906a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
  RAX: ffffffffffffffda RBX: 0000563ec8a8f130 RCX: 00007f4e5132821d
  RDX: 0000000000000000 RSI: 00007f4e518fa07d RDI: 000000000000003b
  RBP: 00007ffca9c90760 R08: 00007f4e513f6b20 R09: 00007ffca9c906f0
  R10: 0000563ec8a8faa0 R11: 0000000000000246 R12: 00007f4e518fa07d
  R13: 0000000000020000 R14: 0000563ec8409e90 R15: 0000563ec8a8fa60
   </TASK>
  ---[ end trace ]---

The Linux kernel CVE team has assigned CVE-2024-38540 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.7 with commit 0c4dcd602817 and fixed in 6.6.33 with commit a658f011d89d
	Issue introduced in 5.7 with commit 0c4dcd602817 and fixed in 6.8.12 with commit 627493443f3a
	Issue introduced in 5.7 with commit 0c4dcd602817 and fixed in 6.9.3 with commit 8b799c00cea6
	Issue introduced in 5.7 with commit 0c4dcd602817 and fixed in 6.10 with commit 78cfd17142ef

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-38540
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/infiniband/hw/bnxt_re/qplib_fp.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/a658f011d89dd20cf2c7cb4760ffd79201700b98
	https://git.kernel.org/stable/c/627493443f3a8458cb55cdae1da254a7001123bc
	https://git.kernel.org/stable/c/8b799c00cea6fcfe5b501bbaeb228c8821acb753
	https://git.kernel.org/stable/c/78cfd17142ef70599d6409cbd709d94b3da58659