usbdevice: validate string descriptor index

[Old-Ding]

Closes #4782

Summary

• Validate USB string descriptor indices before reading string tables.
• Return the Microsoft OS string only when an OS compatible ID descriptor has been registered.
• Stall EP0 for unknown or unregistered string indices instead of reading str_intf out of bounds or dereferencing a null string.

Testing

• git diff --check origin/master...HEAD
• Verified the touched file uses CRLF line endings and has no UTF-8 BOM.
• Not run: RT-Thread build or USB device utest, because this Windows host does not have scons, a C compiler, or an embedded cross toolchain installed.

[github-actions]

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[github-actions]

📌 Code Review Assignment

🏷️ Tag: components

Reviewers: @Maihuanyi

Changed Files (Click to expand)

• components/legacy/usb/usbdevice/core/usbdevice_core.c

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📊 Current Review Status (Last Updated: 2026-07-01 16:00 CST)

• ⌛ @Maihuanyi Pending Review

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[github-actions]

MemBrowse Memory Report

No memory changes detected for:

• at32f415-start
• esp32-c3
• gd32105r-start
• hc32f334
• hpmicro-hpm5301evklite
• infineon-psoc6
• k230
• loongson-ls1cdev
• nordic-nrf51822
• nuvoton-m487
• nxp-lpc1114
• qemu-virt64-aarch64
• raspberry-pico-rp2040
• renesas-ra2l1
• simulator
• stm32f407-rt-spark
• stm32l475-atk-pandora-llvm
• wch-ch32v208w-r0
• x86
• xuantie-e901plus