CVE-2026-93120usb: gadget: configfs: fix out-of-bounds read of qw_sign

Official description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: configfs: fix out-of-bounds read of qw_sign os_desc_qw_sign_show() passes OS_STRING_QW_SIGN_LEN as the input length to utf16s_to_utf8s(), but that argument counts UTF-16 code units while OS_STRING_QW_SIGN_LEN (14) is the byte size of qw_sign[]. The array holds only OS_STRING_QW_SIGN_LEN / 2 (7) code units, so the conversion reads up to 7 units (14 bytes) past the end of qw_sign[] into the following members of struct gadget_info when the stored signature fills the array without a NUL terminator, exposing those bytes through the configfs attribute. The store path halves the count for its input bound but passes the full byte count as the utf8s_to_utf16s() output limit; use the destination code-unit count in both directions.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/b895dbed8ac9e12a5ffa1a2165575a8469f8340d
• https://git.kernel.org/stable/c/9b45125501aad2dff7730970461b455b0e0658ee
• https://git.kernel.org/stable/c/f6da500b0f8106882598b6dec87fe37d653946cf
• https://git.kernel.org/stable/c/a28c486434634f6d1e120711d2b09f3eddea6c98
• https://git.kernel.org/stable/c/7e94cb967778e074411940db4db97f22ed77560c
• https://git.kernel.org/stable/c/afbf39c0f2297c6abef6d670a82a2079b0836191
• https://git.kernel.org/stable/c/36315a330e067f7773196940552feacb1debbef1
• https://git.kernel.org/stable/c/f63edb54d8f738f9c21e2068c777ae1c097df6b7