Date: Fri, 21 Jan 2005 18:09:17 +0000 (UTC) From: Bosko Milekic <bmilekic@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/conf NOTES files options src/sys/kern kern_malloc.c src/sys/vm memguard.c memguard.h Message-ID: <200501211809.j0LI9Hh3092619@repoman.freebsd.org>
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bmilekic 2005-01-21 18:09:17 UTC
FreeBSD src repository
Modified files:
sys/conf NOTES files options
sys/kern kern_malloc.c
Added files:
sys/vm memguard.c memguard.h
Log:
Bring in MemGuard, a very simple and small replacement allocator
designed to help detect tamper-after-free scenarios, a problem more
and more common and likely with multithreaded kernels where race
conditions are more prevalent.
Currently MemGuard can only take over malloc()/realloc()/free() for
particular (a) malloc type(s) and the code brought in with this
change manually instruments it to take over M_SUBPROC allocations
as an example. If you are planning to use it, for now you must:
1) Put "options DEBUG_MEMGUARD" in your kernel config.
2) Edit src/sys/kern/kern_malloc.c manually, look for
"XXX CHANGEME" and replace the M_SUBPROC comparison with
the appropriate malloc type (this might require additional
but small/simple code modification if, say, the malloc type
is declared out of scope).
3) Build and install your kernel. Tune vm.memguard_divisor
boot-time tunable which is used to scale how much of kmem_map
you want to allott for MemGuard's use. The default is 10,
so kmem_size/10.
ToDo:
1) Bring in a memguard(9) man page.
2) Better instrumentation (e.g., boot-time) of MemGuard taking
over malloc types.
3) Teach UMA about MemGuard to allow MemGuard to override zone
allocations too.
4) Improve MemGuard if necessary.
This work is partly based on some old patches from Ian Dowse.
Revision Changes Path
1.1296 +7 -0 src/sys/conf/NOTES
1.985 +1 -0 src/sys/conf/files
1.490 +3 -0 src/sys/conf/options
1.138 +53 -0 src/sys/kern/kern_malloc.c
1.1 +222 -0 src/sys/vm/memguard.c (new)
1.1 +31 -0 src/sys/vm/memguard.h (new)
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