Olivier Gayot f4e39e0ffb block: fix conversion of GPT partition name to 7-bit ... commit e06472bab2 upstream. 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 <amulhern@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: stable@vger.kernel.org Signed-off-by: Olivier Gayot <olivier.gayot@canonical.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20250305022154.3903128-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2025-03-13 12:58:27 +01:00
..
acorn.c	block/partitions/acorn: Remove redundant assignments	2022-04-23 07:15:26 -06:00
aix.c
amiga.c	block/partition: fix signedness issue for Amiga partitions	2023-07-05 16:34:56 -06:00
atari.c	block/partitions/atari: Remove redundant assignment	2022-04-23 07:15:26 -06:00
atari.h
check.h	block: Convert read_part_sector() to use a folio	2022-08-02 12:34:03 -04:00
cmdline.c	block: fix and simplify blkdevparts= cmdline parsing	2024-06-12 11:11:35 +02:00
core.c	block: fix potential invalid pointer dereference in blk_add_partition	2024-10-04 16:29:01 +02:00
efi.c	block: fix conversion of GPT partition name to 7-bit	2025-03-13 12:58:27 +01:00
efi.h	block: remove genhd.h	2022-02-02 07:49:59 -07:00
ibm.c
karma.c
Kconfig
ldm.c	block/partitions/ldm: Remove redundant assignments	2022-04-23 07:15:26 -06:00
ldm.h	partitions: ldm: remove the initial kernel-doc notation	2025-02-08 09:51:43 +01:00
mac.c	partitions: mac: fix handling of bogus partition table	2025-02-21 13:57:18 +01:00
mac.h
Makefile
msdos.c
osf.c
sgi.c
sun.c
sysv68.c
ultrix.c