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malform html tag may crash w3m #9

kcwu opened this issue Aug 12, 2016 · 1 comment


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commented Aug 12, 2016

How to reproduce

 echo '0000000000000000000000000000000000000000000000000000000000000>000000000000000000<button type=>0<i></button><div>0' | ./w3m -T text/html -dump

gdb log

Program received signal SIGSEGV, Segmentation fault.
0x0000000000473b09 in onAnchor (a=0x3030303030, line=2, pos=18) at anchor.c:109
109         if (bpcmp(bp, a->start) < 0)
(gdb) p a
$1 = (Anchor *) 0x3030303030
(gdb) bt
#0  0x0000000000473b09 in onAnchor (a=0x3030303030, line=2, pos=18) at anchor.c:109
#1  0x0000000000474f53 in shiftAnchorPosition (al=0x7d5c40, hl=0x7d5ca0, line=2, pos=18, shift=18) at anchor.c:538
#2  0x000000000044f54f in formUpdateBuffer (a=0x7d9000, buf=0x7cde00, form=0x7d8f80) at form.c:490
#3  0x000000000044ea36 in formResetBuffer (buf=0x7cde00, formitem=0x7d5c40) at form.c:268
#4  0x000000000042c5b8 in loadHTMLBuffer (f=0x7fffffffd140, newBuf=0x7cde00) at file.c:6752
#5  0x0000000000416a40 in loadSomething (f=0x7fffffffd140, loadproc=0x42c47f <loadHTMLBuffer>, defaultbuf=0x7cde00) at file.c:224
#6  0x000000000041c7e6 in loadGeneralFile (path=0x7bcf00 "button-type.html", current=0x0, referer=0xffffffffffffffff <error: Cannot access memory at address 0xffffffffffffffff>, flag=0, request=0x0) at file.c:2241
#7  0x00000000004070d1 in main (argc=3, argv=0x7fffffffd468, envp=0x7fffffffd488) at main.c:1017

Looks like something overflow and overwrite "a" pointer.

This is found by afl-fuzz

tats added a commit that referenced this issue Aug 15, 2016


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commented Aug 15, 2016

Fixed, thank you.

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