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Commit c625d1c2 authored by H. Peter Anvin's avatar H. Peter Anvin Committed by Matt Fleming
Browse files

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: default avatarH. Peter Anvin <hpa@linux.intel.com>
[ Bug and style fixes. ]
Signed-off-by: default avatarRoy Franz <roy.franz@linaro.org>
Signed-off-by: default avatarLeif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 9bb40191

arch/x86/boot/compressed/eboot.c

+1 −2
Original line number Diff line number Diff line
@@ -1087,8 +1087,7 @@ struct boot_params *make_boot_params(struct efi_config *c) 
	hdr->type_of_loader = 0x21;



	/* Convert unicode cmdline to ascii */

	cmdline_ptr = efi_convert_cmdline_to_ascii(sys_table, image,

						   &options_size);

	cmdline_ptr = efi_convert_cmdline(sys_table, image, &options_size);

	if (!cmdline_ptr)

		goto fail;

	hdr->cmd_line_ptr = (unsigned long)cmdline_ptr;

drivers/firmware/efi/efi-stub-helper.c

+67 −20
Original line number Diff line number Diff line
@@ -535,53 +535,100 @@ static efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg, 
	return status;

}



/*

 * 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,

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;



	for (i = 0; i < options_size - 1; i++)

		*s1++ = *s2++;

	s2 = (const u16 *)options;



	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;

}