Hi Pedro,
> The issue pointed out by
>
> https://gcc.gnu.org/ml/gcc-patches/2018-11/msg02592.html
>
> is still present in this version.
Doh! Yes I meant to fix that one too, but forgot.
> Also, noticed a typo here:
>
>> +/* If DMGL_NO_RECURE_LIMIT is not enabled, then this is the value used as
>
> Typo: "RECURE"
Oops - thanks.
OK, revised (v5) patch attached. Is this version acceptable to all ?
Cheers
Nick
Index: include/demangle.h
===================================================================
--- include/demangle.h (revision 266771)
+++ include/demangle.h (working copy)
@@ -68,6 +68,17 @@
/* If none of these are set, use 'current_demangling_style' as the default. */
#define DMGL_STYLE_MASK (DMGL_AUTO|DMGL_GNU|DMGL_LUCID|DMGL_ARM|DMGL_HP|DMGL_EDG|DMGL_GNU_V3|DMGL_JAVA|DMGL_GNAT|DMGL_DLANG|DMGL_RUST)
+/* Disable a limit on the depth of recursion in mangled strings.
+ Note if this limit is disabled then stack exhaustion is possible when
+ demangling pathologically complicated strings. Bug reports about stack
+ exhaustion when the option is enabled will be rejected. */
+#define DMGL_NO_RECURSE_LIMIT (1 << 18)
+
+/* If DMGL_NO_RECURSE_LIMIT is not enabled, then this is the value used as
+ the maximum depth of recursion allowed. It should be enough for any
+ real-world mangled name. */
+#define DEMANGLE_RECURSION_LIMIT 1024
+
/* Enumeration of possible demangling styles.
Lucid and ARM styles are still kept logically distinct, even though
Index: libiberty/cp-demangle.c
===================================================================
--- libiberty/cp-demangle.c (revision 266771)
+++ libiberty/cp-demangle.c (working copy)
@@ -2852,21 +2852,35 @@
static struct demangle_component *
d_function_type (struct d_info *di)
{
- struct demangle_component *ret;
+ struct demangle_component *ret = NULL;
- if (! d_check_char (di, 'F'))
- return NULL;
- if (d_peek_char (di) == 'Y')
+ if ((di->options & DMGL_NO_RECURSE_LIMIT) == 0)
{
- /* Function has C linkage. We don't print this information.
- FIXME: We should print it in verbose mode. */
- d_advance (di, 1);
+ if (di->recursion_level > DEMANGLE_RECURSION_LIMIT)
+ /* FIXME: There ought to be a way to report
+ that the recursion limit has been reached. */
+ return NULL;
+
+ di->recursion_level ++;
}
- ret = d_bare_function_type (di, 1);
- ret = d_ref_qualifier (di, ret);
- if (! d_check_char (di, 'E'))
- return NULL;
+ if (d_check_char (di, 'F'))
+ {
+ if (d_peek_char (di) == 'Y')
+ {
+ /* Function has C linkage. We don't print this information.
+ FIXME: We should print it in verbose mode. */
+ d_advance (di, 1);
+ }
+ ret = d_bare_function_type (di, 1);
+ ret = d_ref_qualifier (di, ret);
+
+ if (! d_check_char (di, 'E'))
+ ret = NULL;
+ }
+
+ if ((di->options & DMGL_NO_RECURSE_LIMIT) == 0)
+ di->recursion_level --;
return ret;
}
@@ -6203,6 +6217,7 @@
di->expansion = 0;
di->is_expression = 0;
di->is_conversion = 0;
+ di->recursion_level = 0;
}
/* Internal implementation for the demangler. If MANGLED is a g++ v3 ABI
@@ -6242,6 +6257,20 @@
cplus_demangle_init_info (mangled, options, strlen (mangled), &di);
+ /* PR 87675 - Check for a mangled string that is so long
+ that we do not have enough stack space to demangle it. */
+ if (((options & DMGL_NO_RECURSE_LIMIT) == 0)
+ /* This check is a bit arbitrary, since what we really want to do is to
+ compare the sizes of the di.comps and di.subs arrays against the
+ amount of stack space remaining. But there is no portable way to do
+ this, so instead we use the recursion limit as a guide to the maximum
+ size of the arrays. */
+ && (unsigned long) di.num_comps > DEMANGLE_RECURSION_LIMIT)
+ {
+ /* FIXME: We need a way to indicate that a stack limit has been reached. */
+ return 0;
+ }
+
{
#ifdef CP_DYNAMIC_ARRAYS
__extension__ struct demangle_component comps[di.num_comps];
Index: libiberty/cp-demangle.h
===================================================================
--- libiberty/cp-demangle.h (revision 266771)
+++ libiberty/cp-demangle.h (working copy)
@@ -122,6 +122,9 @@
/* Non-zero if we are parsing the type operand of a conversion
operator, but not when in an expression. */
int is_conversion;
+ /* If DMGL_NO_RECURSE_LIMIT is not active then this is set to
+ the current recursion level. */
+ unsigned int recursion_level;
};
/* To avoid running past the ending '\0', don't:
Index: libiberty/cplus-dem.c
===================================================================
--- libiberty/cplus-dem.c (revision 266771)
+++ libiberty/cplus-dem.c (working copy)
@@ -146,6 +146,7 @@
int *proctypevec; /* Indices of currently processed remembered typevecs. */
int proctypevec_size;
int nproctypes;
+ unsigned int recursion_level;
};
#define PRINT_ANSI_QUALIFIERS (work -> options & DMGL_ANSI)
@@ -1292,6 +1293,7 @@
free ((char *) work -> btypevec);
work->btypevec = NULL;
work->bsize = 0;
+ work->numb = 0;
}
if (work -> ktypevec != NULL)
{
@@ -1298,6 +1300,7 @@
free ((char *) work -> ktypevec);
work->ktypevec = NULL;
work->ksize = 0;
+ work->numk = 0;
}
}
@@ -1331,8 +1334,15 @@
for (i = 0; i < from->numk; i++)
{
- int len = strlen (from->ktypevec[i]) + 1;
+ int len;
+ if (from->ktypevec[i] == NULL)
+ {
+ to->ktypevec[i] = NULL;
+ continue;
+ }
+
+ len = strlen (from->ktypevec[i]) + 1;
to->ktypevec[i] = XNEWVEC (char, len);
memcpy (to->ktypevec[i], from->ktypevec[i], len);
}
@@ -1342,8 +1352,15 @@
for (i = 0; i < from->numb; i++)
{
- int len = strlen (from->btypevec[i]) + 1;
+ int len;
+ if (from->btypevec[i] == NULL)
+ {
+ to->btypevec[i] = NULL;
+ continue;
+ }
+
+ len = strlen (from->btypevec[i]) + 1;
to->btypevec[i] = XNEWVEC (char , len);
memcpy (to->btypevec[i], from->btypevec[i], len);
}
@@ -1401,6 +1418,7 @@
free ((char*) work->tmpl_argvec);
work->tmpl_argvec = NULL;
+ work->ntmpl_args = 0;
}
if (work->previous_argument)
{
@@ -4478,6 +4496,7 @@
}
/* Lose all the info related to B and K type codes. */
+
static void
forget_B_and_K_types (struct work_stuff *work)
{
@@ -4503,6 +4522,7 @@
}
}
}
+
/* Forget the remembered types, but not the type vector itself. */
static void
@@ -4697,6 +4717,16 @@
int result;
int saved_nrepeats;
+ if ((work->options & DMGL_NO_RECURSE_LIMIT) == 0)
+ {
+ if (work->recursion_level > DEMANGLE_RECURSION_LIMIT)
+ /* FIXME: There ought to be a way to report
+ that the recursion limit has been reached. */
+ return 0;
+
+ work->recursion_level ++;
+ }
+
/* The G++ name-mangling algorithm does not remember types on nested
argument lists, unless -fsquangling is used, and in that case the
type vector updated by remember_type is not used. So, we turn
@@ -4723,6 +4753,9 @@
--work->forgetting_types;
work->nrepeats = saved_nrepeats;
+ if ((work->options & DMGL_NO_RECURSE_LIMIT) == 0)
+ --work->recursion_level;
+
return result;
}
