[PATCH] mwifiex: Avoid memset() over-write of WEP key_material
From: Kees Cook <hidden>
Date: 2021-06-17 17:15:30
Also in:
linux-hardening, linux-wireless, lkml
Subsystem:
marvell mwifiex wireless driver, the rest · Maintainers:
Brian Norris, Linus Torvalds
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring array fields.
When preparing to call mwifiex_set_keyparamset_wep(), key_material is
treated very differently from its structure layout (which has only a
single struct mwifiex_ie_type_key_param_set). Instead, add a new type to
the union so memset() can correctly reason about the size of the
structure.
Note that the union ("params", 196 bytes) containing key_material was
not large enough to hold the target of this memset(): sizeof(struct
mwifiex_ie_type_key_param_set) == 60, NUM_WEP_KEYS = 4, so 240
bytes, or 44 bytes past the end of "params". The good news is that
it appears that the command buffer, as allocated, is 2048 bytes
(MWIFIEX_SIZE_OF_CMD_BUFFER), so no neighboring memory appears to be
getting clobbered.
Signed-off-by: Kees Cook <redacted>
---
drivers/net/wireless/marvell/mwifiex/fw.h | 6 ++++++
drivers/net/wireless/marvell/mwifiex/sta_cmd.c | 11 ++++++-----
2 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h
index 470d669c7f14..2ff23ab259ab 100644
--- a/drivers/net/wireless/marvell/mwifiex/fw.h
+++ b/drivers/net/wireless/marvell/mwifiex/fw.h@@ -995,6 +995,11 @@ struct host_cmd_ds_802_11_key_material { struct mwifiex_ie_type_key_param_set key_param_set; } __packed; +struct host_cmd_ds_802_11_key_material_wep { + __le16 action; + struct mwifiex_ie_type_key_param_set key_param_set[NUM_WEP_KEYS]; +} __packed; + struct host_cmd_ds_gen { __le16 command; __le16 size;
@@ -2347,6 +2352,7 @@ struct host_cmd_ds_command { struct host_cmd_ds_wmm_get_status get_wmm_status; struct host_cmd_ds_802_11_key_material key_material; struct host_cmd_ds_802_11_key_material_v2 key_material_v2; + struct host_cmd_ds_802_11_key_material_wep key_material_wep; struct host_cmd_ds_version_ext verext; struct host_cmd_ds_mgmt_frame_reg reg_mask; struct host_cmd_ds_remain_on_chan roc_cfg;
diff --git a/drivers/net/wireless/marvell/mwifiex/sta_cmd.c b/drivers/net/wireless/marvell/mwifiex/sta_cmd.c
index d3a968ef21ef..48ea00da1fc9 100644
--- a/drivers/net/wireless/marvell/mwifiex/sta_cmd.c
+++ b/drivers/net/wireless/marvell/mwifiex/sta_cmd.c@@ -840,14 +840,15 @@ mwifiex_cmd_802_11_key_material_v1(struct mwifiex_private *priv, } if (!enc_key) { - memset(&key_material->key_param_set, 0, - (NUM_WEP_KEYS * - sizeof(struct mwifiex_ie_type_key_param_set))); + struct host_cmd_ds_802_11_key_material_wep *key_material_wep = + (struct host_cmd_ds_802_11_key_material_wep *)key_material; + memset(key_material_wep->key_param_set, 0, + sizeof(key_material_wep->key_param_set)); ret = mwifiex_set_keyparamset_wep(priv, - &key_material->key_param_set, + &key_material_wep->key_param_set[0], &key_param_len); cmd->size = cpu_to_le16(key_param_len + - sizeof(key_material->action) + S_DS_GEN); + sizeof(key_material_wep->action) + S_DS_GEN); return ret; } else memset(&key_material->key_param_set, 0,
--
2.25.1