[1/3] ipw2x00: Avoid field-overflowing memcpy()

Commit Message

Kees Cook Aug. 19, 2021, 8:28 p.m. UTC

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.

libipw_read_qos_param_element() copies a struct libipw_info_element
into a struct libipw_qos_information_element, but is actually wanting to
copy into the larger struct libipw_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 libipw_info_element {
        u8 id;
        u8 len;
        u8 data[];
} __packed;

struct libipw_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 libipw_qos_parameter_info {
        struct libipw_qos_information_element info_element;
        u8 reserved;
        struct libipw_qos_ac_parameter ac_params_record[QOS_QUEUE_NUM];
} __packed;

Cc: Stanislav Yakovlev <[e-mail]>
Cc: Kalle Valo <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: Jakub Kicinski <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Kees Cook <[e-mail]>
---
 .../net/wireless/intel/ipw2x00/libipw_rx.c    | 56 ++++++-------------
 1 file changed, 17 insertions(+), 39 deletions(-)

Comments

Kalle Valo Aug. 21, 2021, 5:15 p.m. UTC | #1

Kees Cook <[e-mail]> wrote:

> 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.
> 
> libipw_read_qos_param_element() copies a struct libipw_info_element
> into a struct libipw_qos_information_element, but is actually wanting to
> copy into the larger struct libipw_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 libipw_info_element {
>         u8 id;
>         u8 len;
>         u8 data[];
> } __packed;
> 
> struct libipw_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 libipw_qos_parameter_info {
>         struct libipw_qos_information_element info_element;
>         u8 reserved;
>         struct libipw_qos_ac_parameter ac_params_record[QOS_QUEUE_NUM];
> } __packed;
> 
> Cc: Stanislav Yakovlev <[e-mail]>
> Cc: Kalle Valo <[e-mail]>
> Cc: "David S. Miller" <[e-mail]>
> Cc: Jakub Kicinski <[e-mail]>
> Cc: [e-mail]
> Cc: [e-mail]
> Signed-off-by: Kees Cook <[e-mail]>

2 patches applied to wireless-drivers-next.git, thanks.

d6b6d1bb80be ipw2x00: Avoid field-overflowing memcpy()
92276c592a6b ray_cs: Split memcpy() to avoid bounds check warning

Patch

diff --git a/drivers/net/wireless/intel/ipw2x00/libipw_rx.c b/drivers/net/wireless/intel/ipw2x00/libipw_rx.c
index 5a2a723e480b..7a684b76f39b 100644
--- a/drivers/net/wireless/intel/ipw2x00/libipw_rx.c
+++ b/drivers/net/wireless/intel/ipw2x00/libipw_rx.c
@@ -927,7 +927,8 @@  static u8 qos_oui[QOS_OUI_LEN] = { 0x00, 0x50, 0xF2 };
 static int libipw_verify_qos_info(struct libipw_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))
@@ -943,57 +944,34 @@  static int libipw_verify_qos_info(struct libipw_qos_information_element
 /*
  * Parse a QoS parameter element
  */
-static int libipw_read_qos_param_element(struct libipw_qos_parameter_info
-					    *element_param, struct libipw_info_element
-					    *info_element)
+static int libipw_read_qos_param_element(
+			struct libipw_qos_parameter_info *element_param,
+			struct libipw_info_element *info_element)
 {
-	int ret = 0;
-	u16 size = sizeof(struct libipw_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 = libipw_verify_qos_info(&element_param->info_element,
-						QOS_OUI_PARAM_SUB_TYPE);
-	return ret;
+	memcpy(element_param, info_element, size);
+	return libipw_verify_qos_info(&element_param->info_element,
+				      QOS_OUI_PARAM_SUB_TYPE);
 }
 
 /*
  * Parse a QoS information element
  */
-static int libipw_read_qos_info_element(struct
-					   libipw_qos_information_element
-					   *element_info, struct libipw_info_element
-					   *info_element)
+static int libipw_read_qos_info_element(
+			struct libipw_qos_information_element *element_info,
+			struct libipw_info_element *info_element)
 {
-	int ret = 0;
-	u16 size = sizeof(struct libipw_qos_information_element) - 2;
+	size_t size = sizeof(struct libipw_qos_information_element) - 2;
 
-	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 = libipw_verify_qos_info(element_info,
-						QOS_OUI_INFO_SUB_TYPE);
-	return ret;
+	memcpy(element_info, info_element, size);
+	return libipw_verify_qos_info(element_info, QOS_OUI_INFO_SUB_TYPE);
 }
 
 /*