kernel.git/block/partitions/efi.c, branch linux-5.10.y

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

2025-03-13T11:47:37Z

commit e06472bab2a5393430cc2fbc3211cd3602422c1e 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 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 Signed-off-by: Greg Kroah-Hartman

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

block/partitions/efi.c: kerneldoc fixing

2014-07-01T16:40:05Z

Adding function documentation and fixing kerneldoc warnings ('field: description' uniformization). Cc: Davidlohr Bueso Cc: Jens Axboe Signed-off-by: Fabian Frederick Signed-off-by: Jens Axboe

block/partitions/efi.c: fix bound check

2013-11-22T00:42:27Z

Use ARRAY_SIZE instead of sizeof to get proper max for label length. Since this is just a read out of bounds it's not that bad, but the problem becomes user-visible eg if one tries to use DEBUG_PAGEALLOC and DEBUG_RODATA, at least with some enhancements from Hiroshi. Of course the destination array can contain garbage when we read beyond the end of source array so that would be another user-visible problem. Signed-off-by: Antti P Miettinen Reviewed-by: Hiroshi Doyu Tested-by: Hiroshi Doyu Cc: Will Drewry Cc: Matt Fleming Acked-by: Davidlohr Bueso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

block/partitions/efi.c: treat size mismatch as a warning, not an error

2013-10-17T04:35:53Z

In commit 27a7c642174e ("partitions/efi: account for pmbr size in lba") we started treating bad sizes in lba field of the partition that has the 0xEE (GPT protective) as errors. However, we may run into these "bad sizes" in the real world if someone uses dd to copy an image from a smaller disk to a bigger disk. Since this case used to work (even without using force_gpt), keep it working and treat the size mismatch as a warning instead of an error. Reported-by: Josh Triplett Reported-by: Sean Paul Signed-off-by: Doug Anderson Reviewed-by: Josh Triplett Acked-by: Davidlohr Bueso Tested-by: Artem Bityutskiy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

partitions/efi: loosen check fot pmbr size in lba

2013-09-15T11:10:16Z

Matt found that commit 27a7c642174e ("partitions/efi: account for pmbr size in lba") caused his GPT formatted eMMC device not to boot. The reason is that this commit enforced Linux to always check the lesser of the whole disk or 2Tib for the pMBR size in LBA. While most disk partitioning tools out there create a pMBR with these characteristics, Microsoft does not, as it always sets the entry to the maximum 32-bit limitation - even though a drive may be smaller than that[1]. Loosen this check and only verify that the size is either the whole disk or 0xFFFFFFFF. No tool in its right mind would set it to any value other than these. [1] http://thestarman.pcministry.com/asm/mbr/GPT.htm#GPTPT Reported-and-tested-by: Matt Porter Signed-off-by: Davidlohr Bueso Signed-off-by: Linus Torvalds