[PATCH v4 0/3] staging: rtl8723bs: fix OOB reads and heap overflow in IE parsing

[Alexandru Hossu <hossu.alexandru@gmail.com>]

v4, addressing the sashiko review comments on v3.

Regarding hardware: I do not have rtl8723bs hardware available.  The
patches in this series are derived from static analysis of the code,
cross-checking against the 802.11 spec, and reviewing the patterns
already in use elsewhere in the same driver.

What changed in v4:

Patch 1 (update_beacon_info, bwmode_update_check):
  - Added unsigned underflow guard: if pkt_len < _BEACON_IE_OFFSET_ +
    WLAN_HDR_A3_LEN the subtraction that computes len would wrap to a
    very large value.  Return early.
  - Swapped the WLAN_EID_VENDOR_SPECIFIC condition so pIE->length ==
    WLAN_WMM_LEN is checked before memcmp(pIE->data, WMM_PARA_OUI, 6)
    to prevent the 6-byte read on a short IE.
  - Fixed bwmode_update_check(): changed pIE->length >
    sizeof(struct HT_info_element) to != to also reject IEs shorter
    than the struct, preventing the read of infos[0] on a zero-length IE.

Patch 2 (issue_assocreq, join_cmd_hdl):
  - Added pIE->length >= 4 guard before the 4-byte OUI memcmps in both
    WLAN_EID_VENDOR_SPECIFIC cases.
  - In issue_assocreq() WLAN_EID_HT_CAPABILITY: added minimum length
    check and replaced pIE->length with sizeof(struct HT_caps_element)
    in rtw_set_ie() to prevent reads past the HT_caps struct.
  - In join_cmd_hdl() WLAN_EID_HT_OPERATION: added minimum length check
    before casting pIE->data to struct HT_info_element * and reading
    infos[0].

Patch 3 (rtw_get_wps_ie, rtw_cfg80211_set_wpa_ie):
  - Added two bounds checks in rtw_get_wps_ie(): break if fewer than
    two header bytes remain; break if the declared payload extends past
    in_len.  Added in_ie[cnt + 1] >= 4 guard before the 4-byte WPS OUI
    memcmp.

Alexandru Hossu (3):
  staging: rtl8723bs: fix OOB reads in update_beacon_info() and
    bwmode_update_check()
  staging: rtl8723bs: fix OOB reads in IE loops in issue_assocreq() and
    join_cmd_hdl()
  staging: rtl8723bs: fix OOB reads in rtw_get_wps_ie() and
    rtw_cfg80211_set_wpa_ie()

 .../staging/rtl8723bs/core/rtw_ieee80211.c    |  9 +++++-
 drivers/staging/rtl8723bs/core/rtw_mlme_ext.c | 30 ++++++++++++++-----
 .../staging/rtl8723bs/core/rtw_wlan_util.c    | 14 +++++++--
 .../staging/rtl8723bs/os_dep/ioctl_cfg80211.c |  8 +++++
 4 files changed, 50 insertions(+), 11 deletions(-)

-- 
2.53.0