CVS commit: [netbsd-8] src/usr.sbin/installboot/arch

["Martin Husemann" <martin%netbsd.org@localhost>]

Module Name:    src
Committed By:   martin
Date:           Sun Jun 24 09:32:03 UTC 2018

Modified Files:
        src/usr.sbin/installboot/arch [netbsd-8]: i386.c

Log Message:
Pull up following revision(s) (requested by kamil in ticket #898):

        usr.sbin/installboot/arch/i386.c: revision 1.41

Fix integer overflow in installboot(8)
Add a sanity check of the disk_buf first three bytes. The original code on
a disk with nul bytes was causing integer overflow and thus calling the
memcmp(3) functin in is_zero() with enormous length.
Verity that the 0th byte is JMP, 1th a signed byte >= 9 to prevent overflow
and 2th byte NOP.

Add a comment explaining the check.

Detected with MKSANITIZER and ASan.


To generate a diff of this commit:
cvs rdiff -u -r1.40 -r1.40.20.1 src/usr.sbin/installboot/arch/i386.c

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