fsck_msdosfs: avoid signed integer overflow in readboot()

readboot() decoded the 32-bit little-endian BIOS Parameter Block and
FSInfo fields by shifting the individual bytes of a u_char array into
place.  The u_char operands are promoted to signed int, so shifting a
most significant byte of 0x80 or greater left by 24 overflows int, which
is undefined behavior.  Use le32dec() from <sys/endian.h> instead, which
is both well defined and easier to read.

No functional change intended.

MFC after:	1 week
Pull Request:	https://github.com/freebsd/freebsd-src/pull/2350

0 files changed, 0 insertions, 0 deletions