CVS commit: src/sys/fs/msdosfs

["Kamil Rytarowski" <kamil%netbsd.org@localhost>]

Module Name:    src
Committed By:   kamil
Date:           Wed Jul 25 22:07:59 UTC 2018

Modified Files:
        src/sys/fs/msdosfs: msdosfs_fat.c

Log Message:
Avoid undefined behavior semantics in msdosfs_fat.c

Do not change signedness bit with left shift.
While there avoid signed integer overflow.
Address both issues with using unsigned type.

msdosfs_fat.c:512:42, left shift of 1 by 31 places cannot be represented in type 'int'
msdosfs_fat.c:521:44, left shift of 1 by 31 places cannot be represented in type 'int'
msdosfs_fat.c:744:14, left shift of 1 by 31 places cannot be represented in type 'int'
msdosfs_fat.c:744:24, signed integer overflow: -2147483648 - 1 cannot be represented in type 'int [20]'
msdosfs_fat.c:840:13, left shift of 1 by 31 places cannot be represented in type 'int'
msdosfs_fat.c:840:36, signed integer overflow: -2147483648 - 1 cannot be represented in type 'int [20]'

Detected with micro-UBSan in the user mode.


To generate a diff of this commit:
cvs rdiff -u -r1.32 -r1.33 src/sys/fs/msdosfs/msdosfs_fat.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.