CVE-2025-22091

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

RDMA/mlx5: Fix page_size variable overflow

Change all variables storing mlx5_umem_mkc_find_best_pgsz() result to unsigned long to support values larger than 31 and avoid overflow.

For example: If we try to register 4GB of memory that is contiguous in physical memory, the driver will optimize the page_size and try to use an mkey with 4GB entity size. The unsigned int page_size variable will overflow to 0 and well hit the WARN_ON() in alloc_cacheable_mr().

WARNING: CPU: 2 PID: 1203 at drivers/infiniband/hw/mlx5/mr.c:1124 alloc_cacheable_mr+0x22/0x580 [mlx5_ib] Modules linked in: mlx5_ib mlx5_core bonding ip6_gre ip6_tunnel tunnel6 ip_gre gre rdma_rxe rdma_ucm ib_uverbs ib_ipoib ib_umad rpcrdma ib_iser libiscsi scsi_transport_iscsi rdma_cm iw_cm ib_cm fuse ib_core [last unloaded: mlx5_core] CPU: 2 UID: 70878 PID: 1203 Comm: rdma_resource_l Tainted: G W 6.14.0-rc4-dirty #43 Tainted: [W]=WARN Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:alloc_cacheable_mr+0x22/0x580 [mlx5_ib] Code: 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 41 52 53 48 83 ec 30 f6 46 28 04 4c 8b 77 08 75 21 <0f> 0b 49 c7 c2 ea ff ff ff 48 8d 65 d0 4c 89 d0 5b 41 5a 41 5c 41 RSP: 0018:ffffc900006ffac8 EFLAGS: 00010246 RAX: 0000000004c0d0d0 RBX: ffff888217a22000 RCX: 0000000000100001 RDX: 00007fb7ac480000 RSI: ffff8882037b1240 RDI: ffff8882046f0600 RBP: ffffc900006ffb28 R08: 0000000000000001 R09: 0000000000000000 R10: 00000000000007e0 R11: ffffea0008011d40 R12: ffff8882037b1240 R13: ffff8882046f0600 R14: ffff888217a22000 R15: ffffc900006ffe00 FS: 00007fb7ed013340(0000) GS:ffff88885fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb7ed1d8000 CR3: 00000001fd8f6006 CR4: 0000000000772eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? __warn+0x81/0x130 ? alloc_cacheable_mr+0x22/0x580 [mlx5_ib] ? report_bug+0xfc/0x1e0 ? handle_bug+0x55/0x90 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? alloc_cacheable_mr+0x22/0x580 [mlx5_ib] create_real_mr+0x54/0x150 [mlx5_ib] ib_uverbs_reg_mr+0x17f/0x2a0 [ib_uverbs] ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xca/0x140 [ib_uverbs] ib_uverbs_run_method+0x6d0/0x780 [ib_uverbs] ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 [ib_uverbs] ib_uverbs_cmd_verbs+0x19b/0x360 [ib_uverbs] ? walk_system_ram_range+0x79/0xd0 ? ___pte_offset_map+0x1b/0x110 ? __pte_offset_map_lock+0x80/0x100 ib_uverbs_ioctl+0xac/0x110 [ib_uverbs] __x64_sys_ioctl+0x94/0xb0 do_syscall_64+0x50/0x110 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fb7ecf0737b Code: ff ff ff 85 c0 79 9b 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 7d 2a 0f 00 f7 d8 64 89 01 48 RSP: 002b:00007ffdbe03ecc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffdbe03edb8 RCX: 00007fb7ecf0737b RDX: 00007ffdbe03eda0 RSI: 00000000c0181b01 RDI: 0000000000000003 RBP: 00007ffdbe03ed80 R08: 00007fb7ecc84010 R09: 00007ffdbe03eed4 R10: 0000000000000009 R11: 0000000000000246 R12: 00007ffdbe03eed4 R13: 000000000000000c R14: 000000000000000c R15: 00007fb7ecc84150

Weakness

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• If possible, choose a language or compiler that performs automatic bounds checking.
• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
• Use libraries or frameworks that make it easier to handle numbers without unexpected consequences.
• Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++). [REF-106]
• Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
• Use unsigned integers where possible. This makes it easier to perform validation for integer overflows. When signed integers are required, ensure that the range check includes minimum values as well as maximum values.
• Understand the programming language’s underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, “not-a-number” calculations, and how the language handles numbers that are too large or too small for its underlying representation. [REF-7]
• Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/92.html

References

• https://git.kernel.org/stable/c/01fd737776ca0f17a96d83cd7f0840ce130b9a02
• https://git.kernel.org/stable/c/05b215d5e219c0228b9c7082ba9bcf176c576646
• https://git.kernel.org/stable/c/e0c09f639ca0e102f250df8787740c2013e9d1b3
• https://git.kernel.org/stable/c/f0c2427412b43cdf1b7b0944749ea17ddb97d5a5