CVE-2026-90226nfc: llcp: avoid userspace overflow on invalid optlen

Official description

In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: avoid userspace overflow on invalid optlen nfc_llcp_getsockopt() casts optval to (u32 __user *) for put_user(), so the kernel always stores 4 bytes regardless of the caller-supplied optlen. The existing min_t(u32, len, sizeof(u32)) only clamps the length reported back to userspace; it does not constrain the store. A call with optlen < 4 therefore writes past the user buffer, violating the getsockopt(2) contract for all five supported optnames. Reject any call with optlen < sizeof(u32) up front. 'len' is int, so a plain size comparison would promote a negative optlen to size_t and slip past the check; an explicit 'len < 0' test is added first to catch negative values before the size compare.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/42859562b7cc4313a84a584f338118edb7087066
• https://git.kernel.org/stable/c/598dcd53c52f8eeb9dd5382198c03960d5d40fcd
• https://git.kernel.org/stable/c/7e40f2f5e7bc06c3ddef781180ce4f7994176547
• https://git.kernel.org/stable/c/35573c6cb081af2f4a7caeea291302aca5484526
• https://git.kernel.org/stable/c/b4c5abaea06292e1dddb70eac1b51589b32c77a3
• https://git.kernel.org/stable/c/8bf228fa02b1ed8ce622fb81fa8edc42be9aeb67
• https://git.kernel.org/stable/c/bd6f1277b62bc1df348ca21739df2bc546fcd493
• https://git.kernel.org/stable/c/99985bfa8336fadcc69190ba2dcbd5386af3d661