fat: fix buffer overflow in vfat_create_shortname()

When using the string representation of a random counter as part of the base
name, ensure that it is no longer than 4 bytes.

Since we are repeatedly decrementing the counter in a loop until we have found a
unique base name, the counter may wrap around zero; therefore, it is not enough
to mask its higher bits before entering the loop, this must be done inside the
loop.

[[email protected]: use snprintf()]
Signed-off-by: Nikolaus Schulz <[email protected]>
Cc: [email protected]
Signed-off-by: OGAWA Hirofumi <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions