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Diffstat (limited to 'sys/dev/usb')
-rw-r--r--sys/dev/usb/usb.h15
-rw-r--r--sys/dev/usb/usbf_subr.c8
2 files changed, 16 insertions, 7 deletions
diff --git a/sys/dev/usb/usb.h b/sys/dev/usb/usb.h
index ac1c866d202..78439b78b09 100644
--- a/sys/dev/usb/usb.h
+++ b/sys/dev/usb/usb.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: usb.h,v 1.28 2007/06/17 07:53:11 mbalmer Exp $ */
+/* $OpenBSD: usb.h,v 1.29 2007/07/27 09:16:09 mbalmer Exp $ */
/* $NetBSD: usb.h,v 1.69 2002/09/22 23:20:50 augustss Exp $ */
/* $FreeBSD: src/sys/dev/usb/usb.h,v 1.14 1999/11/17 22:33:46 n_hibma Exp $ */
@@ -251,12 +251,21 @@ typedef struct {
} __packed usb_endpoint_descriptor_t;
#define USB_ENDPOINT_DESCRIPTOR_SIZE 7
+/*
+ * Note: The length of the USB string descriptor is stored in a one byte
+ * value and can therefore be no longer than 255 bytes. Two bytes are
+ * used for the length itself and the descriptor type, a theoretical maximum
+ * of 253 bytes is left for the actual string data. Since the strings are
+ * encoded as 2-byte unicode characters, only 252 bytes or 126 two-byte
+ * characters can be used. USB_MAX_STRING_LEN is defined as 127, leaving
+ * space for the terminal '\0' character in C strings.
+ */
typedef struct {
uByte bLength;
uByte bDescriptorType;
- uWord bString[127];
+ uWord bString[126];
} __packed usb_string_descriptor_t;
-#define USB_MAX_STRING_LEN 128
+#define USB_MAX_STRING_LEN 127
#define USB_LANGUAGE_TABLE 0 /* # of the string language id table */
/* Hub specific request */
diff --git a/sys/dev/usb/usbf_subr.c b/sys/dev/usb/usbf_subr.c
index 6971f1d8582..3fc93cf128f 100644
--- a/sys/dev/usb/usbf_subr.c
+++ b/sys/dev/usb/usbf_subr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: usbf_subr.c,v 1.9 2007/06/15 11:41:48 mbalmer Exp $ */
+/* $OpenBSD: usbf_subr.c,v 1.10 2007/07/27 09:16:09 mbalmer Exp $ */
/*
* Copyright (c) 2006 Uwe Stuehler <uwe@openbsd.org>
@@ -308,8 +308,8 @@ usbf_add_string(usbf_device_handle dev, const char *string)
dev->string_id == USBF_STRING_ID_MAX)
return USBF_EMPTY_STRING_ID;
- if ((len = strlen(string)) > USB_MAX_STRING_LEN)
- len = USB_MAX_STRING_LEN;
+ if ((len = strlen(string)) >= USB_MAX_STRING_LEN)
+ len = USB_MAX_STRING_LEN - 1;
oldsize = dev->sdesc_size;
newsize = oldsize + 2 + 2 * len;
@@ -322,7 +322,7 @@ usbf_add_string(usbf_device_handle dev, const char *string)
sd = (usb_string_descriptor_t *)((char *)sd + oldsize);
sd->bLength = newsize - oldsize;
sd->bDescriptorType = UDESC_STRING;
- for (i = 0; string[i] != '\0'; i++)
+ for (i = 0; string[i] != '\0' && i < len; i++)
USETW(sd->bString[i], string[i]);
id = dev->string_id++;