[dot]heap-over-flow(off-by-null) in lib/common/shapes.c
tested on f8b9e035 / ubuntu 16.04 / clang / ASAN
Hi, I've came upon an heap-over-flow
parse_reclbl(lib/common/shapes.c:3311), you could trigger it by loading the content below with: dot filename
digraph structs {
struct [shape=record,label="<"];
}
ASAN report:
==14380==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6020000001f2 at pc 0x7ffff79fa166 bp 0x7fffffffdc60 sp 0x7fffffffdc58
WRITE of size 1 at 0x6020000001f2 thread T0
#0 0x7ffff79fa165 in parse_reclbl /root/graphviz/lib/common/shapes.c:3311:8
#1 0x7ffff79ecd77 in record_init /root/graphviz/lib/common/shapes.c:3556:9
#2 0x7ffff7a1a9e9 in common_init_node /root/graphviz/lib/common/utils.c:653:5
#3 0x7ffff2b13c1d in dot_init_node /root/graphviz/lib/dotgen/dotinit.c:40:5
#4 0x7ffff2b13c1d in dot_init_node_edge /root/graphviz/lib/dotgen/dotinit.c:81
#5 0x7ffff2b1a4a4 in dotLayout /root/graphviz/lib/dotgen/dotinit.c:308:5
#6 0x7ffff2b17517 in doDot /root/graphviz/lib/dotgen/dotinit.c:463:2
#7 0x7ffff2b17517 in dot_layout /root/graphviz/lib/dotgen/dotinit.c:509
#8 0x7ffff784e153 in gvLayoutJobs /root/graphviz/lib/gvc/gvlayout.c:85:2
#9 0x516f3b in main /root/graphviz/cmd/dot/dot.c:132:6
#10 0x7ffff65ff82f in __libc_start_main /build/glibc-LK5gWL/glibc-2.23/csu/../csu/libc-start.c:291
#11 0x41aa58 in _start (/usr/local/bin/dot+0x41aa58)
0x6020000001f2 is located 0 bytes to the right of 2-byte region [0x6020000001f0,0x6020000001f2)
allocated by thread T0 here:
#0 0x4dec88 in malloc (/usr/local/bin/dot+0x4dec88)
#1 0x7ffff790efe4 in gmalloc /root/graphviz/lib/common/memory.c:47:10
#2 0x7ffff790efe4 in zmalloc /root/graphviz/lib/common/memory.c:25
SUMMARY: AddressSanitizer: heap-buffer-overflow /root/graphviz/lib/common/shapes.c:3311:8 in parse_reclbl
Shadow bytes around the buggy address:
0x0c047fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff8000: fa fa 05 fa fa fa 00 03 fa fa 00 05 fa fa 00 fa
0x0c047fff8010: fa fa 00 00 fa fa 00 00 fa fa fd fd fa fa fd fd
0x0c047fff8020: fa fa 07 fa fa fa fd fd fa fa 00 01 fa fa 00 00
=>0x0c047fff8030: fa fa 00 fa fa fa 02 fa fa fa 02 fa fa fa[02]fa
0x0c047fff8040: fa fa fd fa fa fa 00 fa fa fa fa fa fa fa fa fa
0x0c047fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8060: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8070: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8080: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==14380==ABORTING