This is the mail archive of the
gdb-cvs@sourceware.org
mailing list for the GDB project.
[binutils-gdb] Fix heap-buffer-overflow in explicit_location_lex_one
- From: Yao Qi <qiyao at sourceware dot org>
- To: gdb-cvs at sourceware dot org
- Date: 15 Aug 2016 11:30:15 -0000
- Subject: [binutils-gdb] Fix heap-buffer-overflow in explicit_location_lex_one
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=b31f9478185764487b1dcfb2803ed9c399c40ed1
commit b31f9478185764487b1dcfb2803ed9c399c40ed1
Author: Yao Qi <yao.qi@linaro.org>
Date: Mon Aug 15 12:28:56 2016 +0100
Fix heap-buffer-overflow in explicit_location_lex_one
I build GDB with -fsanitize=address, and see the error in tests,
(gdb) PASS: gdb.linespec/ls-errs.exp: lang=C++: break 3 foo
break -line 3 foo^M
=================================================================^M
==4401==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000047487 at pc 0x819d8e bp 0x7fff4e4e6bb0 sp 0x7fff4e4e6ba8^M
READ of size 1 at 0x603000047487 thread T0^[[1m^[[0m^M
#0 0x819d8d in explicit_location_lex_one /home/yao/SourceCode/gnu/gdb/git/gdb/location.c:502^M
#1 0x81a185 in string_to_explicit_location(char const**, language_defn const*, int) /home/yao/SourceCode/gnu/gdb/git/gdb/location.c:556^M
#2 0x81ac10 in string_to_event_location(char**, language_defn const*) /home/yao/SourceCode/gnu/gdb/git/gdb/location.c:687^
the code in question is:
> /* Special case: C++ operator,. */
> if (language->la_language == language_cplus
> && strncmp (*inp, "operator", 8) <--- [1]
> && (*inp)[9] == ',')
> (*inp) += 9;
> ++(*inp);
The error is caused by the access to (*inp)[9] if 9 is out of its bounds.
However [1] looks odd to me, because if strncmp returns true (non-zero),
the following check "(*inp)[9] == ','" makes no sense any more. I
suspect it was a typo in the code we meant to "strncmp () == 0". Another
problem in the code above is that if *inp is "operator,", we first
increment *inp by 9, and then increment it by one again, which is wrong
to me. We should only increment *inp by 8 to skip "operator", and go
back to the loop header to decide where we stop.
gdb:
2016-08-15 Yao Qi <yao.qi@linaro.org>
* location.c (explicit_location_lex_one): Compare the return
value of strncmp with zero. Don't check (*inp)[9]. Increment
*inp by 8.
Diff:
---
gdb/ChangeLog | 6 ++++++
gdb/location.c | 5 ++---
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 91e8b71..62aa129 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2016-08-15 Yao Qi <yao.qi@linaro.org>
+
+ * location.c (explicit_location_lex_one): Compare the return
+ value of strncmp with zero. Don't check (*inp)[9]. Increment
+ *inp by 8.
+
2016-08-11 Pedro Alves <palves@redhat.com>
PR gdb/20413
diff --git a/gdb/location.c b/gdb/location.c
index 071d262..65116c7 100644
--- a/gdb/location.c
+++ b/gdb/location.c
@@ -498,9 +498,8 @@ explicit_location_lex_one (const char **inp,
{
/* Special case: C++ operator,. */
if (language->la_language == language_cplus
- && strncmp (*inp, "operator", 8)
- && (*inp)[9] == ',')
- (*inp) += 9;
+ && strncmp (*inp, "operator", 8) == 0)
+ (*inp) += 8;
++(*inp);
}
}