[BUG] Stack-buffer overflow conf.c #474
Description
Tinyproxy version
Git Master
Issue
I found a stack overflow using a static analyzer and verified it using a Fuzzer with ASAN.
The buffer q in conf.c line 420 may overflow in line 430.
To reproduce use following input:
p'
Full ASAN output:
READ of size 1 at 0x7ffe2c49c560 thread T0
#0 0x4e25d6 in config_parse /home/tom/Projects/tinyproxy/src/conf.c:430:24
#1 0x4e1ee8 in load_config_file /home/tom/Projects/tinyproxy/src/conf.c:459:13
#2 0x4e1615 in reload_config_file /home/tom/Projects/tinyproxy/src/conf.c:499:15
#3 0x511f46 in reload_config /home/tom/Projects/tinyproxy/src/main.c:264:15
#4 0x512419 in main /home/tom/Projects/tinyproxy/src/main.c:335:13
#5 0x7f71e1629209 (/lib/x86_64-linux-gnu/libc.so.6+0x29209)
#6 0x7f71e16292bb in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x292bb)
#7 0x41f530 in _start (/usr/local/bin/tinyproxy+0x41f530)
Address 0x7ffe2c49c560 is located in stack of thread T0 at offset 2080 in frame
#0 0x4e1f8f in config_parse /home/tom/Projects/tinyproxy/src/conf.c:419
This frame has 1 object(s):
[32, 2080) 'buffer' (line 420) <== Memory access at offset 2080 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork
(longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow /home/tom/Projects/tinyproxy/src/conf.c:430:24 in config_parse
Shadow bytes around the buggy address:
0x10004588b850: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10004588b860: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10004588b870: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10004588b880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10004588b890: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x10004588b8a0: 00 00 00 00 00 00 00 00 00 00 00 00[f3]f3 f3 f3
0x10004588b8b0: f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 00 00 00 00
0x10004588b8c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10004588b8d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10004588b8e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10004588b8f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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
==582418==ABORTING