[PATCH] more robust config file parsing in udev/devnaming.c

[PATCH] more robust config file parsing in udev/devnaming.c

[Arnd Bergmann]

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.

	Arnd <><

=== namedev.c 1.32 vs edited ==--- 1.32/namedev.c	Tue Nov 18 02:22:01 2003
+++ edited/namedev.c	Tue Nov 18 17:41:44 2003
@@ -144,37 +144,15 @@
 		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 @@
 	/* 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 @@
 	}
 
 	/* 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 @@
 			/* 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 @@
 			/* 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 @@
 			/* 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 @@
 			/* 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 @@
 			/* 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 @@
 			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 @@
 			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 @@
 	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 @@
 		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 @@
 			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 @@
 		}
 		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 @@
 			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 @@
 		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 @@
 		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 @@
 				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 @@
 	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 @@
 		char *dig;
 		char name[NAME_SIZE];
 		if (pos) {
-			strcpy(name, pos+2);
+			strfieldcpy(name, pos+2);
 			*pos = 0x00;
 			switch (pos[1]) {
 			case 'n':
=== udev.h 1.18 vs edited ==--- 1.18/udev.h	Tue Oct 21 23:28:31 2003
+++ edited/udev.h	Tue Nov 18 17:41:44 2003
@@ -69,6 +69,12 @@
 	int minor;
 	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);



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Re: [PATCH] more robust config file parsing in udev/devnaming.c

[Greg KH]

On Tue, Nov 18, 2003 at 06:29:25PM +0100, Arnd Bergmann wrote:
> 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.

Thanks a lot for this patch, I've applied it.  We should probably
continue on, and not die if we can't read a line of the config file,
that's the nicest way :)

thanks,

greg k-h


-------------------------------------------------------
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Does SourceForge.net help you be more productive?  Does it
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Re: [PATCH] more robust config file parsing in udev/devnaming.c

[Greg KH]

On Tue, Nov 18, 2003 at 06:29:25PM +0100, Arnd Bergmann wrote:
> 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.

Thanks a lot for this patch, I've applied it.  We should probably
continue on, and not die if we can't read a line of the config file,
that's the nicest way :)

thanks,

greg k-h


-------------------------------------------------------
This SF.net email is sponsored by: SF.net Giveback Program.
Does SourceForge.net help you be more productive?  Does it
help you create better code?  SHARE THE LOVE, and help us help
YOU!  Click Here: http://sourceforge.net/donate/
_______________________________________________
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Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel