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Message-Id: <20210806201106.2871169-1-keescook@chromium.org>
Date: Fri, 6 Aug 2021 13:11:06 -0700
From: Kees Cook <keescook@...omium.org>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Kees Cook <keescook@...omium.org>,
Darshan D V <darshandv10@...il.com>,
Aditya Srivastava <yashsri421@...il.com>,
devel@...verdev.osuosl.org,
Larry Finger <Larry.Finger@...inger.net>,
William Durand <will+git@...d.me>,
Dan Carpenter <dan.carpenter@...cle.com>,
linux-kernel@...r.kernel.org, linux-staging@...ts.linux.dev,
linux-hardening@...r.kernel.org
Subject: [PATCH] staging: rtl8192e: Avoid field-overflowing memcpy()
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.
Split the 3 addr memcpy() into 3 memcpy() calls so the compiler doesn't
think an overflowing memcpy() happens against the addr1 field (the
neighbors are intended to be copied as well).
rtllib_read_qos_param_element() copies a struct rtllib_info_element
into a struct rtllib_qos_information_element, but is actually wanting to
copy into the larger struct rtllib_qos_parameter_info (the contents of
ac_params_record[] is later examined). Refactor the routine to perform
centralized checks, and copy the entire contents directly (since the id
and len members match the elementID and length members):
struct rtllib_info_element {
u8 id;
u8 len;
u8 data[];
} __packed;
struct rtllib_qos_information_element {
u8 elementID;
u8 length;
u8 qui[QOS_OUI_LEN];
u8 qui_type;
u8 qui_subtype;
u8 version;
u8 ac_info;
} __packed;
struct rtllib_qos_parameter_info {
struct rtllib_qos_information_element info_element;
u8 reserved;
struct rtllib_qos_ac_parameter ac_params_record[QOS_QUEUE_NUM];
} __packed;
Cc: Darshan D V <darshandv10@...il.com>
Cc: Aditya Srivastava <yashsri421@...il.com>
Cc: devel@...verdev.osuosl.org
Cc: Larry Finger <Larry.Finger@...inger.net>
Signed-off-by: Kees Cook <keescook@...omium.org>
---
drivers/staging/rtl8192e/rtllib_crypt_ccmp.c | 4 +-
drivers/staging/rtl8192e/rtllib_rx.c | 57 ++++++--------------
2 files changed, 20 insertions(+), 41 deletions(-)
diff --git a/drivers/staging/rtl8192e/rtllib_crypt_ccmp.c b/drivers/staging/rtl8192e/rtllib_crypt_ccmp.c
index b60e2a109ce4..ed968c01c7ff 100644
--- a/drivers/staging/rtl8192e/rtllib_crypt_ccmp.c
+++ b/drivers/staging/rtl8192e/rtllib_crypt_ccmp.c
@@ -133,7 +133,9 @@ static int ccmp_init_iv_and_aad(struct rtllib_hdr_4addr *hdr,
pos = (u8 *) hdr;
aad[0] = pos[0] & 0x8f;
aad[1] = pos[1] & 0xc7;
- memcpy(aad + 2, hdr->addr1, 3 * ETH_ALEN);
+ memcpy(&aad[2], &hdr->addr1, ETH_ALEN);
+ memcpy(&aad[8], &hdr->addr2, ETH_ALEN);
+ memcpy(&aad[14], &hdr->addr3, ETH_ALEN);
pos = (u8 *) &hdr->seq_ctl;
aad[20] = pos[0] & 0x0f;
aad[21] = 0; /* all bits masked */
diff --git a/drivers/staging/rtl8192e/rtllib_rx.c b/drivers/staging/rtl8192e/rtllib_rx.c
index c2209c033838..e3d0a361d370 100644
--- a/drivers/staging/rtl8192e/rtllib_rx.c
+++ b/drivers/staging/rtl8192e/rtllib_rx.c
@@ -1556,6 +1556,8 @@ static int rtllib_verify_qos_info(struct rtllib_qos_information_element
*info_element, int sub_type)
{
+ if (info_element->elementID != QOS_ELEMENT_ID)
+ return -1;
if (info_element->qui_subtype != sub_type)
return -1;
if (memcmp(info_element->qui, qos_oui, QOS_OUI_LEN))
@@ -1570,57 +1572,32 @@ static int rtllib_verify_qos_info(struct rtllib_qos_information_element
/* Parse a QoS parameter element */
-static int rtllib_read_qos_param_element(struct rtllib_qos_parameter_info
- *element_param,
- struct rtllib_info_element
- *info_element)
+static int rtllib_read_qos_param_element(
+ struct rtllib_qos_parameter_info *element_param,
+ struct rtllib_info_element *info_element)
{
- int ret = 0;
- u16 size = sizeof(struct rtllib_qos_parameter_info) - 2;
+ size_t size = sizeof(*element_param);
- if ((info_element == NULL) || (element_param == NULL))
+ if (!element_param || !info_element || info_element->len != size - 2)
return -1;
- if (info_element->id == QOS_ELEMENT_ID && info_element->len == size) {
- memcpy(element_param->info_element.qui, info_element->data,
- info_element->len);
- element_param->info_element.elementID = info_element->id;
- element_param->info_element.length = info_element->len;
- } else
- ret = -1;
- if (ret == 0)
- ret = rtllib_verify_qos_info(&element_param->info_element,
- QOS_OUI_PARAM_SUB_TYPE);
- return ret;
+ memcpy(element_param, info_element, size);
+ return rtllib_verify_qos_info(&element_param->info_element,
+ QOS_OUI_PARAM_SUB_TYPE);
}
/* Parse a QoS information element */
-static int rtllib_read_qos_info_element(struct rtllib_qos_information_element
- *element_info,
- struct rtllib_info_element
- *info_element)
+static int rtllib_read_qos_info_element(
+ struct rtllib_qos_information_element *element_info,
+ struct rtllib_info_element *info_element)
{
- int ret = 0;
- u16 size = sizeof(struct rtllib_qos_information_element) - 2;
+ size_t size = sizeof(*element_info);
- if (element_info == NULL)
+ if (!element_info || !info_element || info_element->len != size - 2)
return -1;
- if (info_element == NULL)
- return -1;
-
- if ((info_element->id == QOS_ELEMENT_ID) &&
- (info_element->len == size)) {
- memcpy(element_info->qui, info_element->data,
- info_element->len);
- element_info->elementID = info_element->id;
- element_info->length = info_element->len;
- } else
- ret = -1;
- if (ret == 0)
- ret = rtllib_verify_qos_info(element_info,
- QOS_OUI_INFO_SUB_TYPE);
- return ret;
+ memcpy(element_info, info_element, size);
+ return rtllib_verify_qos_info(element_info, QOS_OUI_INFO_SUB_TYPE);
}
--
2.30.2
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