CVE-2021-47080

/// Technical description

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

RDMA/core: Prevent divide-by-zero error triggered by the user

The user_entry_size is supplied by the user and later used as a

denominator to calculate number of entries. The zero supplied by the user

will trigger the following divide-by-zero error:

divide error: 0000 [#1] SMP KASAN PTI

CPU: 4 PID: 497 Comm: c_repro Not tainted 5.13.0-rc1+ #281

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014

RIP: 0010:ib_uverbs_handler_UVERBS_METHOD_QUERY_GID_TABLE+0x1b1/0x510

Code: 87 59 03 00 00 e8 9f ab 1e ff 48 8d bd a8 00 00 00 e8 d3 70 41 ff 44 0f b7 b5 a8 00 00 00 e8 86 ab 1e ff 31 d2 4c 89 f0 31 ff <49> f7 f5 48 89 d6 48 89 54 24 10 48 89 04 24 e8 1b ad 1e ff 48 8b

RSP: 0018:ffff88810416f828 EFLAGS: 00010246

RAX: 0000000000000008 RBX: 1ffff1102082df09 RCX: ffffffff82183f3d

RDX: 0000000000000000 RSI: ffff888105f2da00 RDI: 0000000000000000

RBP: ffff888

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References