efi: x86: Handle arbitrary Unicode characters
Instead of truncating UTF-16 assuming all characters is ASCII,
properly convert it to UTF-8.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
[ Bug and style fixes. ]
Signed-off-by: Roy Franz <roy.franz@linaro.org>
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
diff --git a/drivers/firmware/efi/efi-stub-helper.c b/drivers/firmware/efi/efi-stub-helper.c
index a168dd2..eb6d4be 100644
--- a/drivers/firmware/efi/efi-stub-helper.c
+++ b/drivers/firmware/efi/efi-stub-helper.c
@@ -536,52 +536,99 @@
}
/*
+ * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
+ * This overestimates for surrogates, but that is okay.
+ */
+static int efi_utf8_bytes(u16 c)
+{
+ return 1 + (c >= 0x80) + (c >= 0x800);
+}
+
+/*
+ * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
+ */
+static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
+{
+ unsigned int c;
+
+ while (n--) {
+ c = *src++;
+ if (n && c >= 0xd800 && c <= 0xdbff &&
+ *src >= 0xdc00 && *src <= 0xdfff) {
+ c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
+ src++;
+ n--;
+ }
+ if (c >= 0xd800 && c <= 0xdfff)
+ c = 0xfffd; /* Unmatched surrogate */
+ if (c < 0x80) {
+ *dst++ = c;
+ continue;
+ }
+ if (c < 0x800) {
+ *dst++ = 0xc0 + (c >> 6);
+ goto t1;
+ }
+ if (c < 0x10000) {
+ *dst++ = 0xe0 + (c >> 12);
+ goto t2;
+ }
+ *dst++ = 0xf0 + (c >> 18);
+ *dst++ = 0x80 + ((c >> 12) & 0x3f);
+ t2:
+ *dst++ = 0x80 + ((c >> 6) & 0x3f);
+ t1:
+ *dst++ = 0x80 + (c & 0x3f);
+ }
+
+ return dst;
+}
+
+/*
* Convert the unicode UEFI command line to ASCII to pass to kernel.
* Size of memory allocated return in *cmd_line_len.
* Returns NULL on error.
*/
-static char *efi_convert_cmdline_to_ascii(efi_system_table_t *sys_table_arg,
- efi_loaded_image_t *image,
- int *cmd_line_len)
+static char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
+ efi_loaded_image_t *image,
+ int *cmd_line_len)
{
- u16 *s2;
+ const u16 *s2;
u8 *s1 = NULL;
unsigned long cmdline_addr = 0;
- int load_options_size = image->load_options_size / 2; /* ASCII */
- void *options = image->load_options;
- int options_size = 0;
+ int load_options_chars = image->load_options_size / 2; /* UTF-16 */
+ const u16 *options = image->load_options;
+ int options_bytes = 0; /* UTF-8 bytes */
+ int options_chars = 0; /* UTF-16 chars */
efi_status_t status;
- int i;
u16 zero = 0;
if (options) {
s2 = options;
- while (*s2 && *s2 != '\n' && options_size < load_options_size) {
- s2++;
- options_size++;
+ while (*s2 && *s2 != '\n'
+ && options_chars < load_options_chars) {
+ options_bytes += efi_utf8_bytes(*s2++);
+ options_chars++;
}
}
- if (options_size == 0) {
+ if (!options_chars) {
/* No command line options, so return empty string*/
- options_size = 1;
options = &zero;
}
- options_size++; /* NUL termination */
+ options_bytes++; /* NUL termination */
- status = efi_low_alloc(sys_table_arg, options_size, 0, &cmdline_addr);
+ status = efi_low_alloc(sys_table_arg, options_bytes, 0, &cmdline_addr);
if (status != EFI_SUCCESS)
return NULL;
s1 = (u8 *)cmdline_addr;
- s2 = (u16 *)options;
+ s2 = (const u16 *)options;
- for (i = 0; i < options_size - 1; i++)
- *s1++ = *s2++;
-
+ s1 = efi_utf16_to_utf8(s1, s2, options_chars);
*s1 = '\0';
- *cmd_line_len = options_size;
+ *cmd_line_len = options_bytes;
return (char *)cmdline_addr;
}