The disk_read() and disk_write() functions of the FAT driver use the
blk_dread() and blk_dwrite() respectively. The blk_* APIs read and write
to the devices in terms of the device block size. However, the FAT
driver reads in terms of the device block size (from fat_set_blk_dev and
read_bootsectandvi) and sector size in the rest of the places.
This causes buffer overflows or partial reads when the FAT sector size
is not equal to device block size. Fix this by using blk_dread in
fat_set_blk_dev and read_bootsectandvi instead of disk_read. And update
disk_read/disk_write to handle FAT sector size and block size mismatch.
Changes in v6:
Added a new config to avoid code size impact to platforms that don't
need this.
Tested on
blksz | FAT sector size
------+----------------
4096 | 4096
512 | 512
4096 | 512
512 | 4096
CI test results
---------------
https://github.com/u-boot/u-boot/pull/871
All checks have passed
93 successful checks
No conflicts with base branch
Code size change info
---------------------
arm: (for 1/1 boards) all +32.0 text +32.0
qemu_arm : all +32 text +32
u-boot: add: 0/0, grow: 2/0 bytes: 24/0 (24)
function old new delta
read_bootsectandvi 420 432 +12
fat_set_blk_dev 204 216 +12
aarch64: (for 1/1 boards) all +12.0 rodata -8.0 text +20.0
qemu_arm64 : all +12 rodata -8 text +20
u-boot: add: 0/0, grow: 2/0 bytes: 20/0 (20)
function old new delta
read_bootsectandvi 408 420 +12
fat_set_blk_dev 204 212 +8
aarch64: (for 1/1 boards) all -2.0 data -8.0 rodata +6.0
qcom_qcs9100 : all -2 data -8 rodata +6
u-boot: add: 1/-1, grow: 8/-1 bytes: 708/-224 (484)
function old new delta
disk_rw - 628 +628
read_bootsectandvi 408 428 +20
fat_itr_root 500 520 +20
get_cluster 376 388 +12
set_contents 2076 2084 +8
fat_set_blk_dev 204 212 +8
static.set_fatent_value 536 540 +4
get_fatent 420 424 +4
fat_next_cluster 368 372 +4
disk_read 100 - -100
disk_write 132 8 -124
Changes in v5:
https://lore.kernel.org/u-boot/[email protected]/
- Fix CI error reported in
https://dev.azure.com/u-boot/u-boot/_build/results?buildId=12821&view=logs&j=a007cd84-3be0-5a02-8a7a-a34fb3052485&t=216c79d4-eaff-5600-0b8f-3a63c01a45d6
- All CI tests passed. (Please see https://github.com/u-boot/u-boot/pull/868)
- U-boot SPL for (am335x_evm, am335x_hs_evm, am335x_hs_evm_spi) includes the
FAT driver. The additional checks done in this patch resulted in increased
code size causing it to overshoot the '.sram' area.
- Address this by using the existing disk_read & disk_write routines for
SPL.
- Also bail out in case of sector size mismatch for SPL
Changes in v4:
https://lore.kernel.org/u-boot/[email protected]/
- Fix clang warning reported in
https://source.denx.de/u-boot/u-boot/-/jobs/1365316
- Remove unused function 'size_to_blocks()'
- Triggered CI, it fails with this error
https://dev.azure.com/u-boot/u-boot/_build/results?buildId=12817&view=logs&j=a007cd84-3be0-5a02-8a7a-a34fb3052485&t=216c79d4-eaff-5600-0b8f-3a63c01a45d6&l=405.
But that seems to be seen on top-of-tree without this change also.
Changes in v3:
https://lore.kernel.org/u-boot/[email protected]/
- Respin, no changes
Changes in v2:
https://lore.kernel.org/u-boot/[email protected]/
- fat_sect_size is declared as static
- The else block in disk_write() function has been removed
- The commit message has additional details about testing
v1:
https://lore.kernel.org/u-boot/[email protected]/
Varadarajan Narayanan (2):
fs: fat: Handle 'FAT sector size mismatch'
configs: qcom: Enable FS_FAT_HANDLE_SECTOR_SIZE_MISMATCH
configs/qcom_defconfig | 1 +
fs/fat/Kconfig | 8 +++
fs/fat/fat.c | 152 +++++++++++++++++++++++++++++++++++++++--
fs/fat/fat_write.c | 2 +
4 files changed, 158 insertions(+), 5 deletions(-)
--
2.34.1
