File:  [NetBSD Developer Wiki] / wikisrc / users / maya.mdwn
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Thu Feb 16 00:01:14 2017 UTC (4 years, 8 months ago) by maya
Branches: MAIN
CVS tags: HEAD
Some info on how I've been using asan and coverity
(Not sure if this is sane markdown)

    1: # Tips for using analyzers on NetBSD #
    2: 
    3: ## Address Sanitizer (+UBsan) (preliminary) ##
    4: 
    5: ASan reports memory violations, and detects many off-by-ones. It seems
    6: to produce very high quality reports.
    7: 
    8: It only needs to be compiled on the resulting binary[1]. It cannot compile
    9: static objects so requires some fiddling with makefiles to disable those.
   10: 
   11: I've been running it on netbsd tests in the following manner[2]:
   12: 
   13:     cd /usr/src/tests/lib/libc
   14:     env USETOOLS=never MK_SSP=no HAVE_SSP=no CFLAGS="-fno-omit-frame-pointer -O0 -g -ggdb -U_FORTIFY_SOURCE -fsanitize=address -fsanitize=undefined" LDFLAGS="-lasan -lubsan" make -j20
   15: 
   16:     env ASAN_OPTIONS=alloc_dealloc_mismatch=0 LD_PRELOAD="/usr/lib/libasan.so /usr/lib/libubsan.so" atf-run
   17: 
   18: 1. Seems like this is a cause of worse reports, as in-library functions
   19: are not intercepted.
   20: 
   21: 2. Not even close to canonical commands, should probably be improved.
   22: 
   23: 3. ASAN_OPTIONS=alloc_dealloc_mismatch=0 is because atf-run itself
   24:     triggers a bug. Should have a look at it so this option doesn't
   25:     need to be disabled.
   26: 
   27: Important note: ASan should not be run on production systems. [It can pose a
   28: security risk](http://www.openwall.com/lists/oss-security/2016/02/17/9).
   29: 
   30: ## Coverity ##
   31: 
   32: Coverity is a static analyzer.
   33: 
   34: You can see a part of its output in coverity-updates@, and a lot more
   35: if you go to the website (sign up with your netbsd email or poke someone
   36: for access).
   37: 
   38: A lot of the reports are about strncpy/strcpy or in code that belongs
   39: to GCC (in the case of userland), you can tackle this by limiting
   40: results to a particular directory (click the folder icon). You can
   41: also sort by issue.
   42: 
   43: Some suggestions for things to focus on, as there are many defects
   44: reported:
   45: 
   46: - Setuid programs
   47: - Anything kernel
   48: - Stuff that runs as root
   49: 
   50: - Library or other code you know well already
   51: - Drivers for hardware you actually own and can test
   52: 
   53: Future ideas:
   54: 
   55: - GCC could be told to add ASan flags for all shared objects, making
   56:   it easier to build world with those flags
   57: - We could run all of NetBSD with ASan for some real world tests.
   58: - ASan for kernel? (subr_kmem.c has some flags which do some of the
   59:   work, could it do more?)
   60: - Fuzzers are cool.

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