Author: nickc
Date: Fri Dec 7 10:33:30 2018
New Revision: 266886
URL: https://gcc.gnu.org/viewcvs?rev=266886&root=gcc&view=rev
Log:
Add a recursion limit to libiberty's demangling code. The limit is enabled by default, but can be disabled via a new demangling option.
include * demangle.h (DMGL_NO_RECURSE_LIMIT): Define.
(DEMANGLE_RECURSION_LIMIT): Define
PR 87681
PR 87675
PR 87636
PR 87350
PR 87335
libiberty * cp-demangle.h (struct d_info): Add recursion_level field.
* cp-demangle.c (d_function_type): Add recursion counter.
If the recursion limit is reached and the check is not disabled,
then return with a failure result.
(cplus_demangle_init_info): Initialise the recursion_level field.
(d_demangle_callback): If the recursion limit is enabled, check
for a mangled string that is so long that there is not enough
stack space for the local arrays.
* cplus-dem.c (struct work): Add recursion_level field.
(squangle_mop_up): Set the numb and numk fields to zero.
(work_stuff_copy_to_from): Handle the case where a btypevec or
ktypevec field is NULL.
(demangle_nested_args): Add recursion counter. If
the recursion limit is not disabled and reached, return with a
failure result.
Modified:
trunk/include/ChangeLog
trunk/include/demangle.h
trunk/libiberty/ChangeLog
trunk/libiberty/cp-demangle.c
trunk/libiberty/cp-demangle.h
trunk/libiberty/cplus-dem.c
diff --git a/include/ChangeLog b/include/ChangeLog
index 18655f0..2c4a7bd 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,8 @@
+2018-12-07 Nick Clifton <nickc@redhat.com>
+
+ * demangle.h (DMGL_NO_RECURSE_LIMIT): Define.
+ (DEMANGLE_RECURSION_LIMIT): Define
+
2018-07-14 Nick Clifton <nickc@redhat.com>
2.31 Release point.
diff --git a/include/demangle.h b/include/demangle.h
index b8d57cf..9bb8a19 100644
--- a/include/demangle.h
+++ b/include/demangle.h
@@ -68,6 +68,17 @@ extern "C" {
/* 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
diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index c944f9e..e547a48 100644
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,26 @@
+2018-12-07 Nick Clifton <nickc@redhat.com>
+
+ PR 87681
+ PR 87675
+ PR 87636
+ PR 87350
+ PR 87335
+ * cp-demangle.h (struct d_info): Add recursion_level field.
+ * cp-demangle.c (d_function_type): Add recursion counter.
+ If the recursion limit is reached and the check is not disabled,
+ then return with a failure result.
+ (cplus_demangle_init_info): Initialise the recursion_level field.
+ (d_demangle_callback): If the recursion limit is enabled, check
+ for a mangled string that is so long that there is not enough
+ stack space for the local arrays.
+ * cplus-dem.c (struct work): Add recursion_level field.
+ (squangle_mop_up): Set the numb and numk fields to zero.
+ (work_stuff_copy_to_from): Handle the case where a btypevec or
+ ktypevec field is NULL.
+ (demangle_nested_args): Add recursion counter. If
+ the recursion limit is not disabled and reached, return with a
+ failure result.
+
2018-06-19 Simon Marchi <simon.marchi@ericsson.com>
* configure.ac: Remove AC_PREREQ.
diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c
index 3f2a097..c374e46 100644
--- a/libiberty/cp-demangle.c
+++ b/libiberty/cp-demangle.c
@@ -2843,21 +2843,35 @@ d_ref_qualifier (struct d_info *di, struct demangle_component *sub)
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;
}
@@ -6188,6 +6202,7 @@ cplus_demangle_init_info (const char *mangled, int options, size_t len,
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
@@ -6227,6 +6242,20 @@ d_demangle_callback (const char *mangled, int options,
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];
diff --git a/libiberty/cp-demangle.h b/libiberty/cp-demangle.h
index 51b8a24..d87a830 100644
--- a/libiberty/cp-demangle.h
+++ b/libiberty/cp-demangle.h
@@ -122,6 +122,9 @@ struct d_info
/* 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:
diff --git a/libiberty/cplus-dem.c b/libiberty/cplus-dem.c
index 6d58bd8..8b9646f 100644
--- a/libiberty/cplus-dem.c
+++ b/libiberty/cplus-dem.c
@@ -146,6 +146,7 @@ struct work_stuff
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)
@@ -1292,12 +1293,14 @@ squangle_mop_up (struct work_stuff *work)
free ((char *) work -> btypevec);
work->btypevec = NULL;
work->bsize = 0;
+ work->numb = 0;
}
if (work -> ktypevec != NULL)
{
free ((char *) work -> ktypevec);
work->ktypevec = NULL;
work->ksize = 0;
+ work->numk = 0;
}
}
@@ -1331,8 +1334,15 @@ work_stuff_copy_to_from (struct work_stuff *to, struct work_stuff *from)
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 @@ work_stuff_copy_to_from (struct work_stuff *to, struct work_stuff *from)
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 @@ delete_non_B_K_work_stuff (struct work_stuff *work)
free ((char*) work->tmpl_argvec);
work->tmpl_argvec = NULL;
+ work->ntmpl_args = 0;
}
if (work->previous_argument)
{
@@ -4477,6 +4495,7 @@ remember_Btype (struct work_stuff *work, const char *start,
}
/* Lose all the info related to B and K type codes. */
+
static void
forget_B_and_K_types (struct work_stuff *work)
{
@@ -4502,6 +4521,7 @@ forget_B_and_K_types (struct work_stuff *work)
}
}
}
+
/* Forget the remembered types, but not the type vector itself. */
static void
@@ -4696,6 +4716,16 @@ demangle_nested_args (struct work_stuff *work, const char **mangled,
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
@@ -4722,6 +4752,9 @@ demangle_nested_args (struct work_stuff *work, const char **mangled,
--work->forgetting_types;
work->nrepeats = saved_nrepeats;
+ if ((work->options & DMGL_NO_RECURSE_LIMIT) == 0)
+ --work->recursion_level;
+
return result;
}