X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=udev_remove.c;h=1fd36d24c5f93e5037be42311134c6ba9a1082f7;hb=4272779706c53c635a3fa5431a4e8791402183b4;hp=32cd785984c821267fde164258098ea07b0aa8b9;hpb=02fa9ae58920b431bc37182716dd863f1c482651;p=elogind.git

diff --git a/udev_remove.c b/udev_remove.c
index 32cd78598..1fd36d24c 100644
--- a/udev_remove.c
+++ b/udev_remove.c
@@ -30,8 +30,9 @@
 #include <errno.h>
 #include <sys/stat.h>
 
+#include "udev_libc_wrapper.h"
 #include "udev.h"
-#include "udev_lib.h"
+#include "udev_utils.h"
 #include "udev_version.h"
 #include "namedev.h"
 #include "udev_db.h"
@@ -67,56 +68,30 @@ static int delete_path(const char *path)
 	return 0;
 }
 
-/** Remove all permissions on the device node, before
-  * unlinking it. This fixes a security issue.
-  * If the user created a hard-link to the device node,
-  * he can't use it any longer, because he lost permission
-  * to do so.
-  */
-static int secure_unlink(const char *filename)
-{
-	int retval;
-
-	retval = chown(filename, 0, 0);
-	if (retval) {
-		dbg("chown(%s, 0, 0) failed with error '%s'",
-		    filename, strerror(errno));
-		/* We continue nevertheless.
-		 * I think it's very unlikely for chown
-		 * to fail here, if the file exists.
-		 */
-	}
-	retval = chmod(filename, 0000);
-	if (retval) {
-		dbg("chmod(%s, 0000) failed with error '%s'",
-		    filename, strerror(errno));
-		/* We continue nevertheless. */
-	}
-	retval = unlink(filename);
-	if (errno == ENOENT)
-		retval = 0;
-	if (retval) {
-		dbg("unlink(%s) failed with error '%s'",
-			filename, strerror(errno));
-	}
-	return retval;
-}
-
 static int delete_node(struct udevice *udev)
 {
-	char filename[NAME_SIZE];
-	char partitionname[NAME_SIZE];
+	char filename[PATH_SIZE];
+	char partitionname[PATH_SIZE];
+	struct name_entry *name_loop;
+	struct stat stats;
 	int retval;
 	int i;
-	char *pos;
-	int len;
 	int num;
 
-	snprintf(filename, NAME_SIZE, "%s/%s", udev_root, udev->name);
-	filename[NAME_SIZE-1] = '\0';
+	snprintf(filename, sizeof(filename), "%s/%s", udev_root, udev->name);
+	filename[sizeof(filename)-1] = '\0';
+
+	dbg("checking major/minor of device node '%s'", filename);
+	if (stat(filename, &stats) != 0)
+		return -1;
+
+	if (udev->devt && stats.st_rdev != udev->devt) {
+		info("device node '%s' points to a different device, skip removal", filename);
+		return -1;
+	}
 
 	info("removing device node '%s'", filename);
-	retval = secure_unlink(filename);
+	retval = unlink_secure(filename);
 	if (retval)
 		return retval;
 
@@ -124,14 +99,14 @@ static int delete_node(struct udevice *udev)
 	num = udev->partitions;
 	if (num > 0) {
 		info("removing all_partitions '%s[1-%i]'", filename, num);
-		if (num > PARTITIONS_COUNT) {
+		if (num > 255) {
 			info("garbage from udev database, skip all_partitions removal");
 			return -1;
 		}
 		for (i = 1; i <= num; i++) {
-			strfieldcpy(partitionname, filename);
-			strintcat(partitionname, i);
-			secure_unlink(partitionname);
+			snprintf(partitionname, sizeof(partitionname), "%s%d", filename, i);
+			partitionname[sizeof(partitionname)-1] = '\0';
+			unlink_secure(partitionname);
 		}
 	}
 
@@ -139,12 +114,9 @@ static int delete_node(struct udevice *udev)
 	if (strchr(udev->name, '/'))
 		delete_path(filename);
 
-	foreach_strpart(udev->symlink, " ", pos, len) {
-		char linkname[NAME_SIZE];
-
-		strfieldcpymax(linkname, pos, len+1);
-		snprintf(filename, NAME_SIZE, "%s/%s", udev_root, linkname);
-		filename[NAME_SIZE-1] = '\0';
+	list_for_each_entry(name_loop, &udev->symlink_list, node) {
+		snprintf(filename, sizeof(filename), "%s/%s", udev_root, name_loop->name);
+		filename[sizeof(filename)-1] = '\0';
 
 		dbg("unlinking symlink '%s'", filename);
 		retval = unlink(filename);
@@ -155,7 +127,7 @@ static int delete_node(struct udevice *udev)
 				filename, strerror(errno));
 			return retval;
 		}
-		if (strchr(udev->symlink, '/')) {
+		if (strchr(filename, '/')) {
 			delete_path(filename);
 		}
 	}
@@ -170,26 +142,29 @@ static int delete_node(struct udevice *udev)
 int udev_remove_device(struct udevice *udev)
 {
 	const char *temp;
-	int retval;
 
-	if (udev->type != 'b' && udev->type != 'c')
+	if (udev->type != BLOCK && udev->type != CLASS)
 		return 0;
 
-	retval = udev_db_get_device(udev);
-	if (retval) {
+	if (udev_db_get_device(udev, udev->devpath) == 0) {
+		if (udev->ignore_remove) {
+			dbg("remove event for '%s' requested to be ignored by rule", udev->name);
+			return 0;
+		}
+		dbg("remove name='%s'", udev->name);
+		udev_db_delete_device(udev);
+	} else {
 		/* fall back to kernel name */
 		temp = strrchr(udev->devpath, '/');
 		if (temp == NULL)
 			return -ENODEV;
-		strfieldcpy(udev->name, &temp[1]);
+		strlcpy(udev->name, &temp[1], sizeof(udev->name));
 		dbg("'%s' not found in database, falling back on default name", udev->name);
 	}
 
-	dbg("remove name='%s'", udev->name);
-	udev_db_delete_device(udev);
-
 	/* use full path to the environment */
-	snprintf(udev->devname, NAME_SIZE, "%s/%s", udev_root, udev->name);
+	snprintf(udev->devname, sizeof(udev->devname), "%s/%s", udev_root, udev->name);
+	udev->devname[sizeof(udev->devname)-1] = '\0';
 
 	return delete_node(udev);
 }