patch 8.2.3290: Vim9: compiling dict may use pointer after free

Problem:    Vim9: compiling dict may use pointer after free and leak memory on
            failure.
Solution:   Pass a pointer to generate_PUSHS().  (Zdenek Dohnal, closes #8699)

diff --git a/src/version.c b/src/version.c
index a473ca552fd698fbbfb4211cc4b4bbd5059daed4..905bc4eec0970024649459765ed9db39d2656092 100644 (file)
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3290,
 /**/
     3289,
 /**/

diff --git a/src/vim9compile.c b/src/vim9compile.c
index a487d0065261fc8fc4a15045a97fb6ca01a6b411..1c6e328f00707ae43bcb0919f4a888474c31474b 100644 (file)
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -1172,21 +1172,26 @@ generate_PUSHF(cctx_T *cctx, float_T fnumber)
 
 /*
  * Generate an ISN_PUSHS instruction.
- * Consumes "str".
+ * Consumes "*str".  When freed *str is set to NULL, unless "str" is NULL.
  */
     static int
-generate_PUSHS(cctx_T *cctx, char_u *str)
+generate_PUSHS(cctx_T *cctx, char_u **str)
 {
     isn_T      *isn;
 
     if (cctx->ctx_skip == SKIP_YES)
     {
-       vim_free(str);
+       if (str != NULL)
+           VIM_CLEAR(*str);
        return OK;
     }
     if ((isn = generate_instr_type(cctx, ISN_PUSHS, &t_string)) == NULL)
+    {
+       if (str != NULL)
+           VIM_CLEAR(*str);
        return FAIL;
-    isn->isn_arg.string = str;
+    }
+    isn->isn_arg.string = str == NULL ? NULL : *str;
 
     return OK;
 }
@@ -2785,7 +2790,7 @@ generate_tv_PUSH(cctx_T *cctx, typval_T *tv)
                tv->vval.v_blob = NULL;
                break;
            case VAR_STRING:
-               generate_PUSHS(cctx, tv->vval.v_string);
+               generate_PUSHS(cctx, &tv->vval.v_string);
                tv->vval.v_string = NULL;
                break;
            default:
@@ -3837,7 +3842,7 @@ compile_dict(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
            key = get_literal_key(arg);
            if (key == NULL)
                return FAIL;
-           if (generate_PUSHS(cctx, key) == FAIL)
+           if (generate_PUSHS(cctx, &key) == FAIL)
                return FAIL;
        }
 
@@ -6525,7 +6530,7 @@ compile_assign_index(
        char_u *key_end = to_name_end(p + 1, TRUE);
        char_u *key = vim_strnsave(p + 1, key_end - p - 1);
 
-       r = generate_PUSHS(cctx, key);
+       r = generate_PUSHS(cctx, &key);
     }
     return r;
 }
@@ -6811,7 +6816,7 @@ compile_assignment(char_u *arg, exarg_T *eap, cmdidx_T cmdidx, cctx_T *cctx)
            // Push each line and the create the list.
            FOR_ALL_LIST_ITEMS(l, li)
            {
-               generate_PUSHS(cctx, li->li_tv.vval.v_string);
+               generate_PUSHS(cctx, &li->li_tv.vval.v_string);
                li->li_tv.vval.v_string = NULL;
            }
            generate_NEWLIST(cctx, l->lv_len);
@@ -8520,7 +8525,7 @@ compile_catch(char_u *arg, cctx_T *cctx UNUSED)
        p += len + 2 + dropped;
        if (pat == NULL)
            return FAIL;
-       if (generate_PUSHS(cctx, pat) == FAIL)
+       if (generate_PUSHS(cctx, &pat) == FAIL)
            return FAIL;
 
        if (generate_COMPARE(cctx, EXPR_MATCH, FALSE) == FAIL)
@@ -9008,7 +9013,9 @@ compile_exec(char_u *line_arg, exarg_T *eap, cctx_T *cctx)
        {
            if (p > start)
            {
-               generate_PUSHS(cctx, vim_strnsave(start, p - start));
+               char_u *val = vim_strnsave(start, p - start);
+
+               generate_PUSHS(cctx, &val);
                ++count;
            }
            p += 2;
@@ -9029,7 +9036,9 @@ compile_exec(char_u *line_arg, exarg_T *eap, cctx_T *cctx)
            {
                if (*skipwhite(start) != NUL)
                {
-                   generate_PUSHS(cctx, vim_strsave(start));
+                   char_u *val = vim_strsave(start);
+
+                   generate_PUSHS(cctx, &val);
                    ++count;
                }
                break;
@@ -9847,6 +9856,7 @@ compile_def_function(
            case CMD_execute:
            case CMD_echomsg:
            case CMD_echoerr:
+           // TODO:  "echoconsole"
                    line = compile_mult_expr(p, ea.cmdidx, &cctx);
                    break;
 
@@ -9885,8 +9895,6 @@ compile_def_function(
 #endif
                    break;
 
-           // TODO: any other commands with an expression argument?
-
            case CMD_append:
            case CMD_change:
            case CMD_insert: