From: Lars-Peter Clausen <redacted>
Date: Fri, 6 May 2016 11:22:19 +0000 (+0200)
Subject: lascar-el-usb: lascar_scan(): Fix USB device list leak
X-Git-Tag: libsigrok-0.5.0~428
X-Git-Url: http://sigrok.org/gitweb/?p=libsigrok.git;a=commitdiff_plain;h=ceb2da179f9446b0e61bde7cf7be9133b25683cc

lascar-el-usb: lascar_scan(): Fix USB device list leak

lascar_scan() calls libusb_get_device_list() but never the matching
libusb_free_device_list(). This will leak the memory allocated for the
device list as well as all the devices. To fix this add the missing
libusb_free_device_list().

While we are at it also make sure to handle errors returned by
libusb_get_device_list().

The issue was discovered using the following coccinelle semantic patch:
// <smpl>
@@
identifier devlist;
expression ctx, ret;
statement S;
@@
(
 libusb_get_device_list(ctx, &devlist);
|
 ret = libusb_get_device_list(ctx, &devlist);
 if (ret < 0) S
)
... when != libusb_free_device_list(devlist, ...)
*return ...;
// </smpl>

Signed-off-by: Lars-Peter Clausen <redacted>
---

diff --git a/src/hardware/lascar-el-usb/protocol.c b/src/hardware/lascar-el-usb/protocol.c
index e4fae68f..f7b053f3 100644
--- a/src/hardware/lascar-el-usb/protocol.c
+++ b/src/hardware/lascar-el-usb/protocol.c
@@ -354,12 +354,16 @@ SR_PRIV struct sr_dev_inst *lascar_scan(int bus, int address)
 	struct libusb_device **devlist;
 	libusb_device_handle *dev_hdl;
 	int dummy, i;
+	int ret;
 	unsigned char config[MAX_CONFIGBLOCK_SIZE];
 
 	drvc = di->context;
 	sdi = NULL;
 
-	libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
+	ret = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
+	if (ret < 0)
+		return NULL;
+
 	for (i = 0; devlist[i]; i++) {
 		if (libusb_get_bus_number(devlist[i]) != bus ||
 				libusb_get_device_address(devlist[i]) != address)
@@ -374,6 +378,7 @@ SR_PRIV struct sr_dev_inst *lascar_scan(int bus, int address)
 		libusb_close(dev_hdl);
 		sdi = lascar_identify(config);
 	}
+	libusb_free_device_list(devlist, 1);
 
 	return sdi;
 }