gdb/cp-namespace.c: Fix assert failure caused by malformed user input
Commit Message
Hi Tom,
On Thu, Jul 6, 2023 at 11:40 AM Tom Tromey <tom@tromey.com> wrote:
>
> >>>>> "Aaron" == Aaron Merey via Gdb-patches <gdb-patches@sourceware.org> writes:
> Aaron> - if (strchr (name, '<') == NULL && strchr (name, '(') == NULL)
> Aaron> - gdb_assert (strstr (name, "::") == NULL);
> Aaron> + if (strchr (name, '<') == nullptr && strchr (name, '>') == nullptr
> Aaron> + && strchr (name, '(') == nullptr)
> Aaron> + gdb_assert (strstr (name, "::") == nullptr);
>
> I think it would be better to use strpbrk here, like:
>
> gdb_assert (strpbrk (name, "<(>") != nullptr || strstr (name, "::") == nullptr);
>
> Writing it like this, though, I wonder if a stray ")" could also make it
> to this assert, the way that ">" did.
The stray ')' does trigger the same assert. Below I've tweaked the patch to
prevent the assert with stray ')'.
Aaron
Commit message:
When debugging C++ programs, it is possible to trigger a spurious assert
failure when attempting to set a breakpoint on a malformed symbol name.
Names of the form 'A>::B' and 'A)::B' trigger this assert failure in
cp_lookup_bare_symbol:
$ gdb gdb
[...]
(gdb) br test>::assert
Function "test>::assert" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (test>::assert) pending.
(gdb) start
[...]
cp-namespace.c:181: internal-error: cp_lookup_bare_symbol: Assertion `strstr (name, "::") == NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
----- Backtrace -----
0x5217e2 gdb_internal_backtrace_1
/home/amerey/binutils-gdb/gdb/bt-utils.c:122
0x521885 _Z22gdb_internal_backtracev
/home/amerey/binutils-gdb/gdb/bt-utils.c:168
0xaf8303 internal_vproblem
/home/amerey/binutils-gdb/gdb/utils.c:396
0xaf86be _Z15internal_verrorPKciS0_P13__va_list_tag
/home/amerey/binutils-gdb/gdb/utils.c:476
0xccdb3f _Z18internal_error_locPKciS0_z
/home/amerey/binutils-gdb/gdbsupport/errors.cc:58
0x5dded9 cp_lookup_bare_symbol
/home/amerey/binutils-gdb/gdb/cp-namespace.c:181
0x5de39d cp_lookup_symbol_in_namespace
/home/amerey/binutils-gdb/gdb/cp-namespace.c:328
[...]
Currently this assert is skipped if the symbol name contains '<' or '('.
Fix this spurious failure by also skipping the assert when the symbol
name contains '>' or ')'.
Regression tested on F38 x86_64.
---
gdb/cp-namespace.c | 5 +++--
gdb/testsuite/gdb.cp/namespace.exp | 6 ++++++
2 files changed, 9 insertions(+), 2 deletions(-)
Comments
>>>>> "Aaron" == Aaron Merey <amerey@redhat.com> writes:
Aaron> The stray ')' does trigger the same assert. Below I've tweaked the patch to
Aaron> prevent the assert with stray ')'.
Thank you. This is ok.
Approved-By: Tom Tromey <tom@tromey.com>
Tom
On Fri, Jul 7, 2023 at 5:27 PM Tom Tromey <tom@tromey.com> wrote:
>
> >>>>> "Aaron" == Aaron Merey <amerey@redhat.com> writes:
>
> Aaron> The stray ')' does trigger the same assert. Below I've tweaked the patch to
> Aaron> prevent the assert with stray ')'.
>
> Thank you. This is ok.
>
> Approved-By: Tom Tromey <tom@tromey.com>
Thanks, pushed as commit 4d792107c916.
Aaron
@@ -34,6 +34,7 @@
#include "namespace.h"
#include <map>
#include <string>
+#include <string.h>
static struct block_symbol
cp_lookup_nested_symbol_1 (struct type *container_type,
@@ -177,8 +178,8 @@ cp_lookup_bare_symbol (const struct language_defn *langdef,
/* Note: We can't do a simple assert for ':' not being in NAME because
':' may be in the args of a template spec. This isn't intended to be
a complete test, just cheap and documentary. */
- if (strchr (name, '<') == NULL && strchr (name, '(') == NULL)
- gdb_assert (strstr (name, "::") == NULL);
+ gdb_assert (strpbrk ("<>()", name) != nullptr
+ || strstr (name, "::") == nullptr);
sym = lookup_symbol_in_static_block (name, block, domain);
if (sym.symbol != NULL)
@@ -250,3 +250,9 @@ gdb_test "print AAA::ALPHA" "\\$\[0-9\].* = AAA::ALPHA"
# Regression tests for PR 9496.
gdb_test "whatis ::C::CClass::NestedClass" "type = C::CClass::NestedClass"
gdb_test "whatis ::C::CClass::NestedClass *" "type = C::CClass::NestedClass \\*"
+
+# Break on functions with a malformed name.
+gdb_test "break DNE>::DNE" "" "br malformed \'>\'" \
+ "Make breakpoint pending on future shared library load?.*" "y"
+gdb_test "break DNE)::DNE" "" "br malformed \')\'" \
+ "Make breakpoint pending on future shared library load?.*" "y"