staging: rtl8723bs: fix OOB reads in rtw_get_sec_ie(), rtw_get_wapi_ie(), and rtw_get_wps_attr()

Overview

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

staging: rtl8723bs: fix OOB reads in rtw_get_sec_ie(), rtw_get_wapi_ie(), and rtw_get_wps_attr()

Three IE/attribute parsing functions have missing bounds checks.

rtw_get_sec_ie() and rtw_get_wapi_ie() iterate over a raw IE buffer without verifying that the header bytes (tag + length) are within the remaining buffer before reading them. Additionally, rtw_get_sec_ie() compares the 4-byte WPA OUI at cnt+2 without checking that at least 6 bytes remain, and rtw_get_wapi_ie() compares a 4-byte WAPI OUI at cnt+6 without checking that at least 10 bytes remain.

rtw_get_wps_attr() reads wps_ie[0] and wps_ie+2 unconditionally at entry, before verifying that wps_ielen is large enough to contain the 6-byte WPS IE header (element_id + length + 4-byte OUI). Inside the attribute loop, get_unaligned_be16() is called on attr_ptr and attr_ptr+2 without checking that 4 bytes remain in the buffer.

Add a cnt+2 bounds check before each loop body in rtw_get_sec_ie() and rtw_get_wapi_ie(), guard each multi-byte comparison with a minimum IE length requirement, add a wps_ielen < 6 early return in rtw_get_wps_attr(), and add a 4-byte bounds check in its inner loop.

Affected

• Linux >= 554c0a3abf216c991c5ebddcdb2c08689ecd290b < efa27d487abcdec79669a60a6d94d5d6eceb7c1d
• Linux >= 554c0a3abf216c991c5ebddcdb2c08689ecd290b < 2ea1ce30ead61589214240e8d33d96310fd613e5
• Linux >= 554c0a3abf216c991c5ebddcdb2c08689ecd290b < b27ecba3196f6c14e3809595ebd69c0c2392512a
• Linux >= 554c0a3abf216c991c5ebddcdb2c08689ecd290b < 6ab1161e539fb7a1c8b35ff5a6ced4702e855b9c
• Linux >= 554c0a3abf216c991c5ebddcdb2c08689ecd290b < 4b51ee8a40fe47864197d73cc02b191de7a6b072
• Linux >= 554c0a3abf216c991c5ebddcdb2c08689ecd290b < 729c4e72563bda0f1725db1db9ea08df06f41d9b
• Linux >= 554c0a3abf216c991c5ebddcdb2c08689ecd290b < 1463ca3ec6601cbb097d8d87dbf5dcf1cb86a344
• Linux 4.12

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.