[PATCH] wl1251: Fix possible buffer overflow in wl1251_cmd_scan

Function wl1251_cmd_scan calls memcpy without checking the length.
A user could control that length and trigger a buffer overflow.
Fix by checking the length is within the maximum allowed size.

Signed-off-by: Lee Gibson <redacted>
---
 drivers/net/wireless/ti/wl1251/cmd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ti/wl1251/cmd.c b/drivers/net/wireless/ti/wl1251/cmd.c
index 498c8db2eb48..e4d028a53d91 100644
--- a/drivers/net/wireless/ti/wl1251/cmd.c
+++ b/drivers/net/wireless/ti/wl1251/cmd.c

@@ -455,8 +455,11 @@ int wl1251_cmd_scan(struct wl1251 *wl, u8 *ssid, size_t ssid_len,
 	}
 
 	cmd->params.ssid_len = ssid_len;
-	if (ssid)
-		memcpy(cmd->params.ssid, ssid, ssid_len);
+	if (ssid) {
+		int len = min_t(int, ssid_len, IEEE80211_MAX_SSID_LEN);
+
+		memcpy(cmd->params.ssid, ssid, len);
+	}
 
 	ret = wl1251_cmd_send(wl, CMD_SCAN, cmd, sizeof(*cmd));
 	if (ret < 0) {

-- 
2.25.1

Function wl1251_cmd_scan calls memcpy without checking the length.
Harden by checking the length is within the maximum allowed size.

Signed-off-by: Lee Gibson <redacted>
---
v2: use clamp_val() instead of min_t()

 drivers/net/wireless/ti/wl1251/cmd.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ti/wl1251/cmd.c b/drivers/net/wireless/ti/wl1251/cmd.c
index 498c8db2eb48..d7a869106782 100644
--- a/drivers/net/wireless/ti/wl1251/cmd.c
+++ b/drivers/net/wireless/ti/wl1251/cmd.c

@@ -454,9 +454,12 @@ int wl1251_cmd_scan(struct wl1251 *wl, u8 *ssid, size_t ssid_len,
 		cmd->channels[i].channel = channels[i]->hw_value;
 	}
 
-	cmd->params.ssid_len = ssid_len;
-	if (ssid)
-		memcpy(cmd->params.ssid, ssid, ssid_len);
+	if (ssid) {
+		int len = clamp_val(ssid_len, 0, IEEE80211_MAX_SSID_LEN);
+
+		cmd->params.ssid_len = len;
+		memcpy(cmd->params.ssid, ssid, len);
+	}
 
 	ret = wl1251_cmd_send(wl, CMD_SCAN, cmd, sizeof(*cmd));
 	if (ret < 0) {

-- 
2.25.1

Lee Gibson [off-list ref] wrote:

Function wl1251_cmd_scan calls memcpy without checking the length.
Harden by checking the length is within the maximum allowed size.

Signed-off-by: Lee Gibson <redacted>

Patch applied to wireless-drivers-next.git, thanks.

d10a87a3535c wl1251: Fix possible buffer overflow in wl1251_cmd_scan

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20210428115508.25624-1-leegib@gmail.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches