https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95090
--- Comment #11 from anlauf at gcc dot gnu.org ---
(In reply to Manfred Schwarb from comment #10)
> Is there a way to get useful backtraces? "--enable-checking=yes,extra"
> seems not to be enough...
Maybe some "fortify" option or a "sanitized" version of the compiler?
I tried valgrind, but failed.
Then I decided to do it the hard way running the example under gdb,
and found a third function which needs adjustment.
diff --git a/gcc/fortran/class.c b/gcc/fortran/class.c
index 9aa3eb7282c..db395624a16 100644
--- a/gcc/fortran/class.c
+++ b/gcc/fortran/class.c
@@ -479,11 +479,12 @@ gfc_class_initializer (gfc_typespec *ts, gfc_expr
*init_expr)
static void
get_unique_type_string (char *string, gfc_symbol *derived)
{
- char dt_name[GFC_MAX_SYMBOL_LEN+1];
+ /* Provide sufficient space to hold "Pdtsymbol". */
+ char dt_name[GFC_MAX_SYMBOL_LEN+4];
if (derived->attr.unlimited_polymorphic)
strcpy (dt_name, "STAR");
else
- strcpy (dt_name, gfc_dt_upper_string (derived->name));
+ strncpy (dt_name, gfc_dt_upper_string (derived->name), sizeof (dt_name));
if (derived->attr.unlimited_polymorphic)
sprintf (string, "_%s", dt_name);
else if (derived->module)
@@ -501,7 +502,8 @@ get_unique_type_string (char *string, gfc_symbol *derived)
static void
get_unique_hashed_string (char *string, gfc_symbol *derived)
{
- char tmp[2*GFC_MAX_SYMBOL_LEN+2];
+ /* Provide sufficient space to hold "symbol_Pdtsymbol". */
+ char tmp[2*GFC_MAX_SYMBOL_LEN+5];
get_unique_type_string (&tmp[0], derived);
/* If string is too long, use hash value in hex representation (allow for
extra decoration, cf. gfc_build_class_symbol & gfc_find_derived_vtab).
@@ -523,7 +525,8 @@ unsigned int
gfc_hash_value (gfc_symbol *sym)
{
unsigned int hash = 0;
- char c[2*(GFC_MAX_SYMBOL_LEN+1)];
+ /* Provide sufficient space to hold "symbol_Pdtsymbol". */
+ char c[2*GFC_MAX_SYMBOL_LEN+5];
int i, len;
get_unique_type_string (&c[0], sym);
I have added one protection using strncpy to avoid a buffer overflow.
One could "protect" the temporary buffers by setting the last byte to \0
and add an assert later to detect an overrun.
I'll regtest the above and commit as "obvious" later.
Thanks, Manfred, for providing pointers.
