Found with test sbsaref introduced in [1].
[1] https://patchew.org/QEMU/20241203213629.2482806-1-pierrick.bouvier@linaro.org/
../block/vvfat.c:433:24: runtime error: index 14 out of bounds for type 'uint8_t [11]'
#0 0x56151a66b93a in create_long_filename ../block/vvfat.c:433
#1 0x56151a66f3d7 in create_short_and_long_name ../block/vvfat.c:725
#2 0x56151a670403 in read_directory ../block/vvfat.c:804
#3 0x56151a674432 in init_directories ../block/vvfat.c:964
#4 0x56151a67867b in vvfat_open ../block/vvfat.c:1258
#5 0x56151a3b8e19 in bdrv_open_driver ../block.c:1660
#6 0x56151a3bb666 in bdrv_open_common ../block.c:1985
#7 0x56151a3cadb9 in bdrv_open_inherit ../block.c:4153
#8 0x56151a3c8850 in bdrv_open_child_bs ../block.c:3731
#9 0x56151a3ca832 in bdrv_open_inherit ../block.c:4098
#10 0x56151a3cbe40 in bdrv_open ../block.c:4248
#11 0x56151a46344f in blk_new_open ../block/block-backend.c:457
#12 0x56151a388bd9 in blockdev_init ../blockdev.c:612
#13 0x56151a38ab2d in drive_new ../blockdev.c:1006
#14 0x5615190fca41 in drive_init_func ../system/vl.c:649
#15 0x56151aa796dd in qemu_opts_foreach ../util/qemu-option.c:1135
#16 0x5615190fd2b6 in configure_blockdev ../system/vl.c:708
#17 0x56151910a307 in qemu_create_early_backends ../system/vl.c:2004
#18 0x561519113fcf in qemu_init ../system/vl.c:3685
#19 0x56151a7e438e in main ../system/main.c:47
#20 0x7f72d1a46249 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
#21 0x7f72d1a46304 in __libc_start_main_impl ../csu/libc-start.c:360
#22 0x561517e98510 in _start (/home/user/.work/qemu/build/qemu-system-aarch64+0x3b9b510)
The offset used can easily go beyond entry->name size. It's probably a
bug, but I don't have the time to dive into vfat specifics for now.
This change solves the ubsan issue, and is functionally equivalent, as
anything written past the entry->name array would not be read anyway.
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
0cb3ff7c22