[gcc/devel/c++-coroutines] PR fortran/95530, PR fortran/95537 - Buffer overflows with long symbols

[Iain D Sandoe]

https://gcc.gnu.org/g:bcd96c9cce962ca5b2c6f8459597fb759f945ccf

commit bcd96c9cce962ca5b2c6f8459597fb759f945ccf
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Fri Jun 5 20:30:34 2020 +0200

    PR fortran/95530, PR fortran/95537 - Buffer overflows with long symbols
    
    The testcases for PR95090 and PR95106 trigger buffer overflows with long
    symbols that were found with an instrumented compiler.  Enlarge the
    affected buffers, and add checks that the buffers will suffice.
    
    2020-06-05  Harald Anlauf  <anlauf@gmx.de>
    
    gcc/fortran/
            PR fortran/95530
            PR fortran/95537
            * decl.c (gfc_match_decl_type_spec): Enlarge buffer, and enhance
            string copy to detect buffer overflow.
            * gfortran.h (gfc_common_head): Enlarge buffer.
            * trans-common.c (finish_equivalences): Enhance string copy to
            detect buffer overflow.

Diff:
---
 gcc/fortran/decl.c         | 9 +++++++--
 gcc/fortran/gfortran.h     | 3 ++-
 gcc/fortran/trans-common.c | 6 +++++-
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index 3ad5559c3ec..1c1626d3fa4 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -4094,7 +4094,8 @@ match_byte_typespec (gfc_typespec *ts)
 match
 gfc_match_decl_type_spec (gfc_typespec *ts, int implicit_flag)
 {
-  char name[GFC_MAX_SYMBOL_LEN + 1];
+  /* Provide sufficient space to hold "pdtsymbol".  */
+  char name[GFC_MAX_SYMBOL_LEN + 1 + 3];
   gfc_symbol *sym, *dt_sym;
   match m;
   char c;
@@ -4284,7 +4285,11 @@ gfc_match_decl_type_spec (gfc_typespec *ts, int implicit_flag)
 	    return m;
 	  gcc_assert (!sym->attr.pdt_template && sym->attr.pdt_type);
 	  ts->u.derived = sym;
-	  strcpy (name, gfc_dt_lower_string (sym->name));
+	  const char* lower = gfc_dt_lower_string (sym->name);
+	  size_t len = strnlen (lower, sizeof (name));
+	  gcc_assert (len < sizeof (name));
+	  memcpy (name, lower, len);
+	  name[len] = '\0';
 	}
 
       if (sym && sym->attr.flavor == FL_STRUCT)
diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index 5af44847f9b..0ef7b1b0eff 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -1677,7 +1677,8 @@ typedef struct gfc_common_head
   char use_assoc, saved, threadprivate;
   unsigned char omp_declare_target : 1;
   unsigned char omp_declare_target_link : 1;
-  char name[GFC_MAX_SYMBOL_LEN + 1];
+  /* Provide sufficient space to hold "symbol.eq.1234567890".  */
+  char name[GFC_MAX_SYMBOL_LEN + 1 + 14];
   struct gfc_symbol *head;
   const char* binding_label;
   int is_bind_c;
diff --git a/gcc/fortran/trans-common.c b/gcc/fortran/trans-common.c
index 3775a8bea74..1acc336eacf 100644
--- a/gcc/fortran/trans-common.c
+++ b/gcc/fortran/trans-common.c
@@ -1314,7 +1314,11 @@ finish_equivalences (gfc_namespace *ns)
 	      c->where = ns->proc_name->declared_at;
 	    else if (ns->is_block_data)
 	      c->where = ns->sym_root->n.sym->declared_at;
-	    strcpy (c->name, z->module);
+
+	    size_t len = strlen (z->module);
+	    gcc_assert (len < sizeof (c->name));
+	    memcpy (c->name, z->module, len);
+	    c->name[len] = '\0';
 	  }
 	else
 	  c = NULL;