[PATCH] more robust config file parsing in namedev.c

After getting a number of different crashes for udev reading broken
udev.config files, I decided to try to make the parser a little
more robust.

The behaviour is changed to stop reading the configuration file
and logging the broken entry instead of silently ignoring it (is
that good? It's easy to just print and continue).
All strcpy()'s to a fixed length string are now implicitly limited
to the bounds of the target string.

I kept the -ENODEV return code for now, not sure if there should be
different ones.

2 files changed, 86 insertions, 79 deletions

diff --git a/namedev.c b/namedev.c
index 5970ef0590..a9d66bcad7 100644
--- a/namedev.c
+++ b/namedev.c
@@ -144,37 +144,15 @@ static void dump_dev_list(void)
 		dump_dev(dev);
 	}
 }
-
-static int get_value(const char *left, char **orig_string, char **ret_string)
-{
-	char *temp;
-	char *string = *orig_string;
-
-	/* eat any whitespace */
-	while (isspace(*string))
-		++string;
-
-	/* split based on '=' */
-	temp = strsep(&string, "=");
-	if (strcasecmp(temp, left) == 0) {
-		/* got it, now strip off the '"' */
-		while (isspace(*string))
-			++string;
-		if (*string == '"')
-			++string;
-		temp = strsep(&string, "\"");
-		*ret_string = temp;
-		*orig_string = string;
-		return 0;
-	}
-	return -ENODEV;
-}
 	
 static int get_pair(char **orig_string, char **left, char **right)
 {
 	char *temp;
 	char *string = *orig_string;
 
+	if (!string)
+		return -ENODEV;
+
 	/* eat any whitespace */
 	while (isspace(*string))
 		++string;
@@ -182,22 +160,43 @@ static int get_pair(char **orig_string, char **left, char **right)
 	/* split based on '=' */
 	temp = strsep(&string, "=");
 	*left = temp;
+	if (!string)
+		return -ENODEV;
 
 	/* take the right side and strip off the '"' */
 	while (isspace(*string))
 		++string;
 	if (*string == '"')
 		++string;
+	else
+		return -ENODEV;
+
 	temp = strsep(&string, "\"");
+	if (!string || *temp == '\0')
+		return -ENODEV;
 	*right = temp;
 	*orig_string = string;
 	
 	return 0;
 }
 
+static int get_value(const char *left, char **orig_string, char **ret_string)
+{
+	int retval;
+	char *left_string;
+
+	retval = get_pair(orig_string, &left_string, ret_string);
+	if (retval)
+		return retval;
+	if (strcasecmp(left_string, left) != 0)
+		return -ENODEV;
+	return 0;
+}
+
 static int namedev_init_config(void)
 {
 	char line[255];
+	int lineno;
 	char *temp;
 	char *temp2;
 	char *temp3;
@@ -213,11 +212,13 @@ static int namedev_init_config(void)
 	}
 
 	/* loop through the whole file */
+	lineno = 0;
 	while (1) {
 		/* get a line */
 		temp = fgets(line, sizeof(line), fd);
 		if (temp == NULL)
-			break;
+			goto exit;
+		lineno++;
 
 		dbg_parse("read %s", temp);
 
@@ -244,23 +245,23 @@ static int namedev_init_config(void)
 			/* BUS="bus" */
 			retval = get_value("BUS", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.bus, temp3);
+				break;
+			strfieldcpy(dev.bus, temp3);
 
 			/* file="value" */
 			temp2 = strsep(&temp, ",");
 			retval = get_pair(&temp, &temp2, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.sysfs_file, temp2);
-			strcpy(dev.sysfs_value, temp3);
+				break;
+			strfieldcpy(dev.sysfs_file, temp2);
+			strfieldcpy(dev.sysfs_value, temp3);
 
 			/* NAME="new_name" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("NAME", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.name, temp3);
+				break;
+			strfieldcpy(dev.name, temp3);
 
 			dbg_parse("LABEL name = '%s', bus = '%s', "
 				"sysfs_file = '%s', sysfs_value = '%s'", 
@@ -275,22 +276,22 @@ static int namedev_init_config(void)
 			/* BUS="bus" */
 			retval = get_value("BUS", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.bus, temp3);
+				break;
+			strfieldcpy(dev.bus, temp3);
 
 			/* ID="id" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("id", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.id, temp3);
+				break;
+			strfieldcpy(dev.id, temp3);
 
 			/* NAME="new_name" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("NAME", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.name, temp3);
+				break;
+			strfieldcpy(dev.name, temp3);
 
 			dbg_parse("NUMBER name = '%s', bus = '%s', id = '%s'",
 					dev.name, dev.bus, dev.id);
@@ -303,22 +304,22 @@ static int namedev_init_config(void)
 			/* BUS="bus" */
 			retval = get_value("BUS", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.bus, temp3);
+				break;
+			strfieldcpy(dev.bus, temp3);
 
 			/* PLACE="place" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("place", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.place, temp3);
+				break;
+			strfieldcpy(dev.place, temp3);
 
 			/* NAME="new_name" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("NAME", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.name, temp3);
+				break;
+			strfieldcpy(dev.name, temp3);
 
 			dbg_parse("TOPOLOGY name = '%s', bus = '%s', place = '%s'",
 					dev.name, dev.bus, dev.place);
@@ -331,15 +332,15 @@ static int namedev_init_config(void)
 			/* KERNEL="kernel_name" */
 			retval = get_value("KERNEL", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.kernel_name, temp3);
+				break;
+			strfieldcpy(dev.kernel_name, temp3);
 
 			/* NAME="new_name" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("NAME", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.name, temp3);
+				break;
+			strfieldcpy(dev.name, temp3);
 			dbg_parse("REPLACE name = %s, kernel_name = %s",
 					dev.name, dev.kernel_name);
 		}
@@ -350,29 +351,29 @@ static int namedev_init_config(void)
 			/* PROGRAM="executable" */
 			retval = get_value("PROGRAM", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.exec_program, temp3);
+				break;
+			strfieldcpy(dev.exec_program, temp3);
 
 			/* BUS="bus" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("BUS", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.bus, temp3);
+				break;
+			strfieldcpy(dev.bus, temp3);
 
 			/* ID="id" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("ID", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.id, temp3);
+				break;
+			strfieldcpy(dev.id, temp3);
 
 			/* NAME="new_name" */
 			temp2 = strsep(&temp, ",");
 			retval = get_value("NAME", &temp, &temp3);
 			if (retval)
-				continue;
-			strcpy(dev.name, temp3);
+				break;
+			strfieldcpy(dev.name, temp3);
 			dbg_parse("CALLOUT name = %s, program = %s",
 					dev.name, dev.exec_program);
 		}
@@ -383,7 +384,8 @@ static int namedev_init_config(void)
 			goto exit;
 		}
 	}
-
+	dbg_parse("%s:%d:%Zd: error parsing ``%s''", udev_config_filename,
+		  lineno, temp - line, temp);
 exit:
 	fclose(fd);
 	return retval;
@@ -552,11 +554,11 @@ static int do_callout(struct sysfs_class_device *class_dev, struct udevice *udev
 			continue;
 		if (strncmp(value, dev->id, sizeof(value)) != 0)
 			continue;
-		strcpy(udev->name, dev->name);
+		strfieldcpy(udev->name, dev->name);
 		if (dev->mode != 0) {
 			udev->mode = dev->mode;
-			strcpy(udev->owner, dev->owner);
-			strcpy(udev->group, dev->group);
+			strfieldcpy(udev->owner, dev->owner);
+			strfieldcpy(udev->group, dev->group);
 		}
 		dbg_parse("device callout '%s' becomes '%s' - owner = %s, group = %s, mode = %#o",
 			dev->id, udev->name, 
@@ -571,7 +573,6 @@ static int do_label(struct sysfs_class_device *class_dev, struct udevice *udev,
 	struct sysfs_attribute *tmpattr = NULL;
 	struct config_device *dev;
 	struct list_head *tmp;
-	char *temp = NULL;
 
 	list_for_each(tmp, &config_device_list) {
 		dev = list_entry(tmp, struct config_device, node);
@@ -600,11 +601,11 @@ label_found:
 		if (strcmp(dev->sysfs_value, tmpattr->value) != 0)
 			continue;
 
-		strcpy(udev->name, dev->name);
+		strfieldcpy(udev->name, dev->name);
 		if (dev->mode != 0) {
 			udev->mode = dev->mode;
-			strcpy(udev->owner, dev->owner);
-			strcpy(udev->group, dev->group);
+			strfieldcpy(udev->owner, dev->owner);
+			strfieldcpy(udev->group, dev->group);
 		}
 		dbg_parse("file '%s' with value '%s' becomes '%s' - owner = %s, group = %s, mode = %#o",
 			dev->sysfs_file, dev->sysfs_value, udev->name, 
@@ -633,7 +634,7 @@ static int do_number(struct sysfs_class_device *class_dev, struct udevice *udev,
 			continue;
 
 		found = 0;
-		strcpy(path, sysfs_device->path);
+		strfieldcpy(path, sysfs_device->path);
 		temp = strrchr(path, '/');
 		dbg_parse("NUMBER path = '%s'", path);
 		dbg_parse("NUMBER temp = '%s' id = '%s'", temp, dev->id);
@@ -648,11 +649,11 @@ static int do_number(struct sysfs_class_device *class_dev, struct udevice *udev,
 		}
 		if (!found)
 			continue;
-		strcpy(udev->name, dev->name);
+		strfieldcpy(udev->name, dev->name);
 		if (dev->mode != 0) {
 			udev->mode = dev->mode;
-			strcpy(udev->owner, dev->owner);
-			strcpy(udev->group, dev->group);
+			strfieldcpy(udev->owner, dev->owner);
+			strfieldcpy(udev->group, dev->group);
 		}
 		dbg_parse("device id '%s' becomes '%s' - owner = %s, group = %s, mode = %#o",
 			dev->id, udev->name, 
@@ -681,7 +682,7 @@ static int do_topology(struct sysfs_class_device *class_dev, struct udevice *ude
 			continue;
 
 		found = 0;
-		strcpy(path, sysfs_device->path);
+		strfieldcpy(path, sysfs_device->path);
 		temp = strrchr(path, '/');
 		dbg_parse("TOPOLOGY path = '%s'", path);
 		dbg_parse("TOPOLOGY temp = '%s' place = '%s'", temp, dev->place);
@@ -697,11 +698,11 @@ static int do_topology(struct sysfs_class_device *class_dev, struct udevice *ude
 		if (!found)
 			continue;
 
-		strcpy(udev->name, dev->name);
+		strfieldcpy(udev->name, dev->name);
 		if (dev->mode != 0) {
 			udev->mode = dev->mode;
-			strcpy(udev->owner, dev->owner);
-			strcpy(udev->group, dev->group);
+			strfieldcpy(udev->owner, dev->owner);
+			strfieldcpy(udev->group, dev->group);
 		}
 		dbg_parse("device at '%s' becomes '%s' - owner = %s, group = %s, mode = %#o",
 			dev->place, udev->name, 
@@ -727,11 +728,11 @@ static int do_replace(struct sysfs_class_device *class_dev, struct udevice *udev
 		if (strcmp(dev->kernel_name, class_dev->name) != 0)
 			continue;
 
-		strcpy(udev->name, dev->name);
+		strfieldcpy(udev->name, dev->name);
 		if (dev->mode != 0) {
 			udev->mode = dev->mode;
-			strcpy(udev->owner, dev->owner);
-			strcpy(udev->group, dev->group);
+			strfieldcpy(udev->owner, dev->owner);
+			strfieldcpy(udev->group, dev->group);
 		}
 		dbg_parse("'%s' becomes '%s' - owner = %s, group = %s, mode = %#o",
 			dev->kernel_name, udev->name, 
@@ -766,7 +767,7 @@ static int get_attr(struct sysfs_class_device *class_dev, struct udevice *udev)
 				char path[SYSFS_PATH_MAX];
 
 				dbg_parse("really is a partition...");
-				strcpy(path, class_dev->path);
+				strfieldcpy(path, class_dev->path);
 				temp = strrchr(path, '/');
 				*temp = 0x00;
 				dbg_parse("looking for a class device at '%s'", path);
@@ -810,7 +811,7 @@ static int get_attr(struct sysfs_class_device *class_dev, struct udevice *udev)
 	if (retval == 0)
 		goto done;
 
-	strcpy(udev->name, class_dev->name);
+	strfieldcpy(udev->name, class_dev->name);
 
 done:
 	/* substitute placeholder in NAME  */
@@ -819,7 +820,7 @@ done:
 		char *dig;
 		char name[NAME_SIZE];
 		if (pos) {
-			strcpy(name, pos+2);
+			strfieldcpy(name, pos+2);
 			*pos = 0x00;
 			switch (pos[1]) {
 			case 'b':
diff --git a/udev.h b/udev.h
index cdf1af4fc2..904948d67a 100644
--- a/udev.h
+++ b/udev.h
@@ -70,6 +70,12 @@ struct udevice {
 	mode_t mode;
 };
 
+#define strfieldcpy(to, from) \
+do { \
+	to[sizeof(to)-1] = '\0'; \
+	strncpy(to, from, sizeof(to)-1); \
+} while (0)
+
 extern int udev_add_device(char *path, char *subsystem);
 extern int udev_remove_device(char *path, char *subsystem);