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authorYao Qi <yao.qi@linaro.org>2016-08-15 12:28:56 +0100
committerYao Qi <yao.qi@linaro.org>2016-08-15 12:28:56 +0100
commitb31f9478185764487b1dcfb2803ed9c399c40ed1 (patch)
treec389f702d1401602c7df7e9e73ed4c5d762a7755
parentb69fc9d9f3b68420f7c2b5c57167a1f5c8fac279 (diff)
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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.
-rw-r--r--gdb/ChangeLog6
-rw-r--r--gdb/location.c5
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);
}
}