diff --git a/src/shared/install.c b/src/shared/install.c
index 9e88ac46bd..64d55532e2 100644
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -2827,19 +2827,14 @@ static int presets_find_config(UnitFileScope scope, const char *root_dir, char *
         assert(scope >= 0);
         assert(scope < _UNIT_FILE_SCOPE_MAX);
 
-        switch (scope) {
-        case UNIT_FILE_SYSTEM:
+        if (scope == UNIT_FILE_SYSTEM)
                 dirs = (const char* const*) CONF_PATHS_STRV("systemd/system-preset");
-                break;
 
-        case UNIT_FILE_GLOBAL:
-        case UNIT_FILE_USER:
+        else if (IN_SET(scope, UNIT_FILE_GLOBAL, UNIT_FILE_USER))
                 dirs = (const char* const*) CONF_PATHS_USR_STRV("systemd/user-preset");
-                break;
 
-        default:
+        else
                 assert_not_reached("Invalid unit file scope");
-        }
 
         return conf_files_list_strv(files, ".preset", root_dir, 0, dirs);
 }
diff --git a/src/udev/udev-builtin-usb_id.c b/src/udev/udev-builtin-usb_id.c
index 3525d25048..7bdf6cfbb5 100644
--- a/src/udev/udev-builtin-usb_id.c
+++ b/src/udev/udev-builtin-usb_id.c
@@ -138,13 +138,12 @@ static void set_scsi_type(char *to, const char *from, size_t len) {
 #define USB_DT_INTERFACE                0x04
 
 static int dev_if_packed_info(sd_device *dev, char *ifs_str, size_t len) {
-        _cleanup_free_ char *filename = NULL;
         _cleanup_close_ int fd = -1;
         ssize_t size;
         unsigned char buf[18 + 65535];
         size_t pos = 0;
         unsigned strpos = 0;
-        const char *syspath;
+        const char *filename, *syspath;
         int r;
         struct usb_interface_descriptor {
                 uint8_t bLength;
@@ -161,16 +160,17 @@ static int dev_if_packed_info(sd_device *dev, char *ifs_str, size_t len) {
         r = sd_device_get_syspath(dev, &syspath);
         if (r < 0)
                 return r;
-        if (asprintf(&filename, "%s/descriptors", syspath) < 0)
-                return log_oom();
 
+        filename = strjoina(syspath, "/descriptors");
         fd = open(filename, O_RDONLY|O_CLOEXEC);
         if (fd < 0)
-                return log_device_debug_errno(dev, errno, "Failed to open USB device 'descriptors' file: %m");
+                return log_device_debug_errno(dev, errno, "Failed to open \"%s\": %m", filename);
 
         size = read(fd, buf, sizeof(buf));
-        if (size < 18 || (size_t) size >= sizeof(buf))
-                return -EIO;
+        if (size < 18)
+                return log_device_warning_errno(dev, SYNTHETIC_ERRNO(EIO),
+                                                "Short read from \"%s\"", filename);
+        assert((size_t) size <= sizeof buf);
 
         ifs_str[0] = '\0';
         while (pos + sizeof(struct usb_interface_descriptor) < (size_t) size &&
@@ -179,9 +179,12 @@ static int dev_if_packed_info(sd_device *dev, char *ifs_str, size_t len) {
                 struct usb_interface_descriptor *desc;
                 char if_str[8];
 
-                desc = (struct usb_interface_descriptor *) &buf[pos];
+                desc = (struct usb_interface_descriptor *) (buf + pos);
                 if (desc->bLength < 3)
                         break;
+                if (desc->bLength > size - sizeof(struct usb_interface_descriptor))
+                        return log_device_debug_errno(dev, SYNTHETIC_ERRNO(EIO),
+                                                      "Corrupt data read from \"%s\"", filename);
                 pos += desc->bLength;
 
                 if (desc->bDescriptorType != USB_DT_INTERFACE)