From 99aa998dec83ba180822f70e6d48a514fc81c20d Mon Sep 17 00:00:00 2001 From: Muhammad Bilal Date: Tue, 28 Jul 2026 17:54:54 +0500 Subject: [PATCH] staging: rtl8723bs: fix OOB read / stack overflow in rtw_get_wps_attr() rtw_get_wps_attr() walks WPS attributes inside a WPS IE taken from a wireless management frame. For each candidate attribute it only checks that the fixed 4-byte attribute header (2-byte ID + 2-byte length) fits inside the IE: if (attr_ptr + 4 > wps_ie + wps_ielen) break; u16 attr_id = get_unaligned_be16(attr_ptr); u16 attr_data_len = get_unaligned_be16(attr_ptr + 2); u16 attr_len = attr_data_len + 4; attr_data_len (and therefore attr_len) is read directly from the wire and is never checked against the remaining bytes in the IE before being used as the size of: memcpy(buf_attr, attr_ptr, attr_len); Since attr_len is fully attacker controlled (0 to 65535+4), this is both a heap OOB read of wps_ie, and, more seriously, a stack buffer overflow at several call sites where buf_attr is a single-byte stack variable, e.g. rtw_get_wps_attr_content()'s callers passing WPS_ATTR_SELECTED_REGISTRAR into a stack "u8 sr"/"u8 selected_registrar" (drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c, drivers/staging/rtl8723bs/core/rtw_mlme_ext.c). A crafted WPS IE in a beacon or probe response processed during scanning can therefore smash the stack of the parsing thread. rtw_get_wps_attr_content() itself has no independent length check and simply trusts the attr_len it gets back from rtw_get_wps_attr(), so fixing the bound here also fixes that caller. The "attr_ptr + 4 > wps_ie + wps_ielen" header check above was added by commit 1463ca3ec6601 ("staging: rtl8723bs: fix OOB reads in rtw_get_sec_ie(), rtw_get_wapi_ie(), and rtw_get_wps_attr()"), which bounded the fixed header but never extended the check to cover the variable-length attribute data that follows it. Add that missing check before attr_len is used as a memcpy() length or accepted as a match. Fixes: 554c0a3abf216 ("staging: Add rtl8723bs sdio wifi driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260728125456.32359-2-meatuni001@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/staging/rtl8723bs/core/rtw_ieee80211.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/staging/rtl8723bs/core/rtw_ieee80211.c b/drivers/staging/rtl8723bs/core/rtw_ieee80211.c index 66f476a46aad..2a58a5cdd9f5 100644 --- a/drivers/staging/rtl8723bs/core/rtw_ieee80211.c +++ b/drivers/staging/rtl8723bs/core/rtw_ieee80211.c @@ -741,6 +741,10 @@ u8 *rtw_get_wps_attr(u8 *wps_ie, uint wps_ielen, u16 target_attr_id, u8 *buf_att u16 attr_data_len = get_unaligned_be16(attr_ptr + 2); u16 attr_len = attr_data_len + 4; + /* Reject attributes whose claimed length runs past the IE */ + if (attr_ptr + attr_len > wps_ie + wps_ielen) + break; + if (attr_id == target_attr_id) { target_attr_ptr = attr_ptr;