kernel.git/block/partitions/efi.c, branch linux-6.14.y

block: fix conversion of GPT partition name to 7-bit

2025-03-05T14:40:24Z

The utf16_le_to_7bit function claims to, naively, convert a UTF-16 string to a 7-bit ASCII string. By naively, we mean that it: * drops the first byte of every character in the original UTF-16 string * checks if all characters are printable, and otherwise replaces them by exclamation mark "!". This means that theoretically, all characters outside the 7-bit ASCII range should be replaced by another character. Examples: * lower-case alpha (ɒ) 0x0252 becomes 0x52 (R) * ligature OE (œ) 0x0153 becomes 0x53 (S) * hangul letter pieup (ㅂ) 0x3142 becomes 0x42 (B) * upper-case gamma (Ɣ) 0x0194 becomes 0x94 (not printable) so gets replaced by "!" The result of this conversion for the GPT partition name is passed to user-space as PARTNAME via udev, which is confusing and feels questionable. However, there is a flaw in the conversion function itself. By dropping one byte of each character and using isprint() to check if the remaining byte corresponds to a printable character, we do not actually guarantee that the resulting character is 7-bit ASCII. This happens because we pass 8-bit characters to isprint(), which in the kernel returns 1 for many values > 0x7f - as defined in ctype.c. This results in many values which should be replaced by "!" to be kept as-is, despite not being valid 7-bit ASCII. Examples: * e with acute accent (é) 0x00E9 becomes 0xE9 - kept as-is because isprint(0xE9) returns 1. * euro sign (€) 0x20AC becomes 0xAC - kept as-is because isprint(0xAC) returns 1. This way has broken pyudev utility[1], fixes it by using a mask of 7 bits instead of 8 bits before calling isprint. Link: https://github.com/pyudev/pyudev/issues/490#issuecomment-2685794648 [1] Link: https://lore.kernel.org/linux-block/4cac90c2-e414-4ebb-ae62-2a4589d9dc6e@canonical.com/ Cc: Mulhern Cc: Davidlohr Bueso Cc: stable@vger.kernel.org Signed-off-by: Olivier Gayot Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20250305022154.3903128-1-ming.lei@redhat.com Signed-off-by: Jens Axboe

partitions/efi: use bdev_nr_bytes instead of open coding it

2021-10-19T12:16:50Z

Use the proper helper to read the block device size. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20211019062024.2171074-3-hch@lst.de Signed-off-by: Jens Axboe

partitions/efi: Support non-standard GPT location

2021-08-24T16:09:06Z

Support looking up GPT at a non-standard location specified by a block device driver. Acked-by: Davidlohr Bueso Reviewed-by: Christoph Hellwig Signed-off-by: Dmitry Osipenko Reviewed-by: Ulf Hansson Link: https://lore.kernel.org/r/20210820004536.15791-3-digetx@gmail.com Signed-off-by: Jens Axboe

block: store a gendisk in struct parsed_partitions

2021-08-12T16:31:35Z

Partition scanning only happens on the whole device, so pass a struct gendisk instead of the whole device block_device to the scanners. This allows to simplify printing the device name in various places as the disk name is available in disk->name. Signed-off-by: Christoph Hellwig Reviewed-by: Stefan Haberland Link: https://lore.kernel.org/r/20210810154512.1809898-2-hch@lst.de Signed-off-by: Jens Axboe

block/partitions/efi.c: Fix the efi_partition() kernel-doc header

2021-05-14T15:00:06Z

Fix the following kernel-doc warning: block/partitions/efi.c:685: warning: wrong kernel-doc identifier on line: * efi_partition(struct parsed_partitions *state) Cc: Alexander Viro Signed-off-by: Bart Van Assche Link: https://lore.kernel.org/r/20210513171708.8391-1-bvanassche@acm.org Signed-off-by: Jens Axboe

partitions/efi: Fix partition name parsing in GUID partition entry

2020-03-08T09:00:09Z

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: eec7ecfede74 ("genhd, efi: add efi partition metadata to hd_structs") Reviewed-by: Christoph Hellwig Signed-off-by: Nikolai Merinov Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar 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/

block: switch all files cleared marked as GPLv2 or later to SPDX tags

2019-04-30T22:11:59Z

All these files have some form of the usual GPLv2 or later boilerplate. Switch them to use SPDX tags instead. Reviewed-by: Chaitanya Kulkarni Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

partitions/efi: Fix integer overflow in GPT size calculation

2017-01-17T16:02:31Z

If a GUID Partition Table claims to have more than 2**25 entries, the calculation of the partition table size in alloc_read_gpt_entries() will overflow a 32-bit integer and not enough space will be allocated for the table. Nothing seems to get written out of bounds, but later efi_partition() will read up to 32768 bytes from a 128 byte buffer, possibly OOPSing or exposing information to /proc/partitions and uevents. The problem exists on both 64-bit and 32-bit platforms. Fix the overflow and also print a meaningful debug message if the table size is too large. Signed-off-by: Alden Tondettar Acked-by: Ard Biesheuvel Signed-off-by: Jens Axboe

treewide: Fix typos in printk

2016-04-18T09:23:24Z

This patch fix spelling typos found in printk within various part of the kernel sources. Signed-off-by: Masanari Iida Acked-by: Randy Dunlap Signed-off-by: Jiri Kosina

efi: Rename efi_guid_unparse to efi_guid_to_str

2015-01-08T03:07:44Z

Call it what it does - "unparse" is plain-misleading. Signed-off-by: Borislav Petkov Signed-off-by: Ricardo Neri