Commit d5528d5e authored by Nikolai Merinov's avatar Nikolai Merinov Committed by Ingo Molnar
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partitions/efi: Fix partition name parsing in GUID partition entry 



GUID partition entry defined to have a partition name as 36 UTF-16LE
code units. This means that on big-endian platforms ASCII symbols
would be read with 0xXX00 efi_char16_t character code. In order to
correctly extract ASCII characters from a partition name field we
should be converted from 16LE to CPU architecture.

The problem exists on all big endian platforms.

[ mingo: Minor edits. ]

Fixes: eec7ecfe ("genhd, efi: add efi partition metadata to hd_structs")
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNikolai Merinov <n.merinov@inango-systems.com>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200308080859.21568-29-ardb@kernel.org
Link: https://lore.kernel.org/r/797777312.1324734.1582544319435.JavaMail.zimbra@inango-systems.com/
parent 0347d8c2

block/partitions/efi.c

+26 −9
Original line number Diff line number Diff line
@@ -656,6 +656,31 @@ static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt, 
        return 0;

}



/**

 * utf16_le_to_7bit(): Naively converts a UTF-16LE string to 7-bit ASCII characters

 * @in: input UTF-16LE string

 * @size: size of the input string

 * @out: output string ptr, should be capable to store @size+1 characters

 *

 * Description: Converts @size UTF16-LE symbols from @in string to 7-bit

 * ASCII characters and stores them to @out. Adds trailing zero to @out array.

 */

static void utf16_le_to_7bit(const __le16 *in, unsigned int size, u8 *out)

{

	unsigned int i = 0;



	out[size] = 0;



	while (i < size) {

		u8 c = le16_to_cpu(in[i]) & 0xff;



		if (c && !isprint(c))

			c = '!';

		out[i] = c;

		i++;

	}

}



/**

 * efi_partition(struct parsed_partitions *state)

 * @state: disk parsed partitions
@@ -692,7 +717,6 @@ int efi_partition(struct parsed_partitions *state) 


	for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {

		struct partition_meta_info *info;

		unsigned label_count = 0;

		unsigned label_max;

		u64 start = le64_to_cpu(ptes[i].starting_lba);

		u64 size = le64_to_cpu(ptes[i].ending_lba) -
@@ -713,14 +737,7 @@ int efi_partition(struct parsed_partitions *state) 
		/* Naively convert UTF16-LE to 7 bits. */

		label_max = min(ARRAY_SIZE(info->volname) - 1,

				ARRAY_SIZE(ptes[i].partition_name));

		info->volname[label_max] = 0;

		while (label_count < label_max) {

			u8 c = ptes[i].partition_name[label_count] & 0xff;

			if (c && !isprint(c))

				c = '!';

			info->volname[label_count] = c;

			label_count++;

		}

		utf16_le_to_7bit(ptes[i].partition_name, label_max, info->volname);

		state->parts[i + 1].has_info = true;

	}

	kfree(ptes);

block/partitions/efi.h

+1 −1
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ typedef struct _gpt_entry { 
	__le64 starting_lba;

	__le64 ending_lba;

	gpt_entry_attributes attributes;

	efi_char16_t partition_name[72 / sizeof (efi_char16_t)];

	__le16 partition_name[72/sizeof(__le16)];

} __packed gpt_entry;



typedef struct _gpt_mbr_record {

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