Fix hwasan global overflow. (#76)
* Fix hwasan global overflow.
Crash found with https://source.android.com/devices/tech/debug/hwasan
but also detectable by regular ASan. Here's an ASan crash:
==215690==ERROR: AddressSanitizer: global-buffer-overflow on address
0x55d90f8da140 at pc 0x55d90f8b7503 bp 0x7ffd3dae6100 sp 0x7ffd3dae60f8
READ of size 4 at 0x55d90f8da140 thread T0
#0 0x55d90f8b7502 in word /tmp/awk/lex.c:496
#1 0x55d90f8b939f in yylex /tmp/awk/lex.c:191
#2 0x55d90f894ab9 in yyparse /tmp/awk/awkgram.tab.c:2366
#3 0x55d90f89edc2 in main /tmp/awk/main.c:216
#4 0x7ff263a78bba in __libc_start_main ../csu/libc-start.c:308
#5 0x55d90f8945a9 in _start (/tmp/awk/a.out+0x115a9)
0x55d90f8da141 is located 0 bytes to the right of global variable
'infunc' defined in 'awkgram.y:35:6' (0x55d90f8da140) of size 1
SUMMARY: AddressSanitizer: global-buffer-overflow /tmp/awk/lex.c:496 in word
Shadow bytes around the buggy address:
0x0abba1f133d0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
0x0abba1f133e0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
0x0abba1f133f0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
0x0abba1f13400: f9 f9 f9 f9 00 00 00 00 00 00 00 00 00 00 00 00
0x0abba1f13410: 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
=>0x0abba1f13420: 04 f9 f9 f9 f9 f9 f9 f9[01]f9 f9 f9 f9 f9 f9 f9
0x0abba1f13430: 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
0x0abba1f13440: 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9 04 f9 f9 f9
0x0abba1f13450: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 04 f9 f9 f9
0x0abba1f13460: f9 f9 f9 f9 04 f9 f9 f9 f9 f9 f9 f9 04 f9 f9 f9
0x0abba1f13470: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9
And here's the stack trace from hwasan:
Stack Trace:
RELADDR FUNCTION FILE:LINE
00000000000168d4 word external/one-true-awk/lex.c:496:18
000000000002d1ec yyparse y.tab.c:2460:16
000000000001c82c main external/one-true-awk/main.c:179:2
00000000000b41a0 __libc_init bionic/libc/bionic/libc_init_dynamic.cpp:151:8
As it says, we're doing a 4-byte read from a 1-byte global.
`infunc` is declared as an int but defined as a bool.
Signed-off-by: Evgenii Stepanov <eugenis@google.com>
* Add ASan cflags to makefile.
They're not used by default, but this way they're easily to hand next
time they're wanted.
Bug: http://b/150168534
Test: treehugger
(cherry picked from commit 7b245a02668dcb9f9677b36f5745cfd07cc216bd)
Change-Id: I1302532f27970b3e73df6536238c2777798bd102
diff --git a/lex.c b/lex.c
index 1c23212..81d1cc2 100644
--- a/lex.c
+++ b/lex.c
@@ -30,7 +30,7 @@
#include "ytab.h"
extern YYSTYPE yylval;
-extern int infunc;
+extern bool infunc;
int lineno = 1;
int bracecnt = 0;
diff --git a/makefile b/makefile
index 735436c..95aee3e 100644
--- a/makefile
+++ b/makefile
@@ -22,6 +22,7 @@
# THIS SOFTWARE.
# ****************************************************************/
+CFLAGS = -fsanitize=address -O1 -g -fno-omit-frame-pointer -fno-optimize-sibling-calls
CFLAGS = -g
CFLAGS =
CFLAGS = -O2
