Prevent recursive includes of keymap components

- Add check for recursive includes of keymap components. It relies on
  limiting the include depth. The threshold is currently to 15, which
  seems reasonable with plenty of margin for keymaps in the wild.
- Add corresponding new log message `recursive-include`.
- Add tests for recursive includes.

doc/message-registry.md

@@ -39,6 +39,7 @@ There are currently 54 entries.
 | [XKB-338] | `included-file-not-found` | Could not find a file used in an include statement | Error |
 | [XKB-345] | `unknown-operator` | Use of an operator that is unknown and thus unsupported | Error |
 | [XKB-378] | `duplicate-entry` | An entry is duplicated and will be ignored | Warning |
+| [XKB-386] | `recursive-include` | Included files form cycle | Error |
 | [XKB-407] | `conflicting-key-type-definitions` | Conflicting definitions of a key type | Warning |
 | [XKB-428] | `wrong-scope` | A statement is in a wrong scope and should be moved | Error |
 | [XKB-433] | `missing-default-section` | Missing default section in included file | Warning |
@@ -327,6 +328,14 @@ as numbers and as identifiers `LevelN`, where `N` is in the range (1..8).
   <dt>Summary</dt><dd>An entry is duplicated and will be ignored</dd>
 </dl>
 
+### XKB-386 – Recursive include {#XKB-386}
+
+<dl>
+  <dt>Since</dt><dd>1.7.0</dd>
+  <dt>Type</dt><dd>Error</dd>
+  <dt>Summary</dt><dd>Included files form cycle</dd>
+</dl>
+
 ### XKB-407 – Conflicting key type definitions {#XKB-407}
 
 <dl>
@@ -657,6 +666,7 @@ The modifiers used in `map` or `preserve` entries should be declared using the e
 [XKB-338]: @ref XKB-338
 [XKB-345]: @ref XKB-345
 [XKB-378]: @ref XKB-378
+[XKB-386]: @ref XKB-386
 [XKB-407]: @ref XKB-407
 [XKB-428]: @ref XKB-428
 [XKB-433]: @ref XKB-433

doc/message-registry.yaml

@@ -180,6 +180,11 @@
   added: ALWAYS
   type: warning
   description: "An entry is duplicated and will be ignored"
+- id: "recursive-include"
+  code: 386
+  added: 1.7.0
+  type: error
+  description: "Included files form cycle"
 - id: "conflicting-key-type-definitions"
   code: 407
   added: ALWAYS

src/messages-codes.h

@@ -66,6 +66,8 @@ enum xkb_message_code {
     XKB_ERROR_UNKNOWN_OPERATOR = 345,
     /** An entry is duplicated and will be ignored */
     XKB_WARNING_DUPLICATE_ENTRY = 378,
+    /** Included files form cycle */
+    XKB_ERROR_RECURSIVE_INCLUDE = 386,
     /** Conflicting definitions of a key type */
     XKB_WARNING_CONFLICTING_KEY_TYPE_DEFINITIONS = 407,
     /** A statement is in a wrong scope and should be moved */

src/xkbcomp/compat.c

@@ -86,6 +86,7 @@ typedef struct {
 typedef struct {
     char *name;
     int errorCount;
+    unsigned int include_depth;
     SymInterpInfo default_interp;
     darray(SymInterpInfo) interps;
     LedInfo default_led;
@@ -148,10 +149,12 @@ ReportLedNotArray(CompatInfo *info, LedInfo *ledi, const char *field)
 
 static void
 InitCompatInfo(CompatInfo *info, struct xkb_context *ctx,
+               unsigned int include_depth,
                ActionsInfo *actions, const struct xkb_mod_set *mods)
 {
     memset(info, 0, sizeof(*info));
     info->ctx = ctx;
+    info->include_depth = include_depth;
     info->actions = actions;
     info->mods = *mods;
     info->default_interp.merge = MERGE_OVERRIDE;
@@ -430,7 +433,13 @@ HandleIncludeCompatMap(CompatInfo *info, IncludeStmt *include)
 {
     CompatInfo included;
 
-    InitCompatInfo(&included, info->ctx, info->actions, &info->mods);
+    if (ExceedsIncludeMaxDepth(info->ctx, info->include_depth)) {
+        info->errorCount += 10;
+        return false;
+    }
+
+    InitCompatInfo(&included, info->ctx, 0 /* unused */,
+                   info->actions, &info->mods);
     included.name = include->stmt;
     include->stmt = NULL;
 
@@ -445,7 +454,8 @@ HandleIncludeCompatMap(CompatInfo *info, IncludeStmt *include)
             return false;
         }
 
-        InitCompatInfo(&next_incl, info->ctx, info->actions, &included.mods);
+        InitCompatInfo(&next_incl, info->ctx, info->include_depth + 1,
+                       info->actions, &included.mods);
         next_incl.default_interp = info->default_interp;
         next_incl.default_interp.merge = stmt->merge;
         next_incl.default_led = info->default_led;
@@ -914,7 +924,7 @@ CompileCompatMap(XkbFile *file, struct xkb_keymap *keymap,
     if (!actions)
         return false;
 
-    InitCompatInfo(&info, keymap->ctx, actions, &keymap->mods);
+    InitCompatInfo(&info, keymap->ctx, 0, actions, &keymap->mods);
     info.default_interp.merge = merge;
     info.default_led.merge = merge;
 

src/xkbcomp/include.c

@@ -286,6 +286,20 @@ FindFileInXkbPath(struct xkb_context *ctx, const char *name,
     return file;
 }
 
+bool
+ExceedsIncludeMaxDepth(struct xkb_context *ctx, unsigned int include_depth)
+{
+    if (include_depth >= INCLUDE_MAX_DEPTH) {
+        log_err(ctx,
+                XKB_ERROR_RECURSIVE_INCLUDE,
+                "Exceeded include depth threshold (%d)",
+                INCLUDE_MAX_DEPTH);
+        return true;
+    } else {
+        return false;
+    }
+}
+
 XkbFile *
 ProcessIncludeFile(struct xkb_context *ctx, IncludeStmt *stmt,
                    enum xkb_file_type file_type)
@@ -334,7 +348,5 @@ ProcessIncludeFile(struct xkb_context *ctx, IncludeStmt *stmt,
                     stmt->file);
     }
 
-    /* FIXME: we have to check recursive includes here (or somewhere) */
-
     return xkb_file;
 }

src/xkbcomp/include.h

@@ -27,6 +27,9 @@
 #ifndef XKBCOMP_INCLUDE_H
 #define XKBCOMP_INCLUDE_H
 
+/* Reasonable threshold, with plenty of margin for keymaps in the wild */
+#define INCLUDE_MAX_DEPTH 15
+
 bool
 ParseIncludeMap(char **str_inout, char **file_rtrn, char **map_rtrn,
                 char *nextop_rtrn, char **extra_data);
@@ -36,6 +39,9 @@ FindFileInXkbPath(struct xkb_context *ctx, const char *name,
                   enum xkb_file_type type, char **pathRtrn,
                   unsigned int *offset);
 
+bool
+ExceedsIncludeMaxDepth(struct xkb_context *ctx, unsigned int include_depth);
+
 XkbFile *
 ProcessIncludeFile(struct xkb_context *ctx, IncludeStmt *stmt,
                    enum xkb_file_type file_type);

src/xkbcomp/keycodes.c

@@ -47,6 +47,7 @@ typedef struct {
 typedef struct {
     char *name;
     int errorCount;
+    unsigned int include_depth;
 
     xkb_keycode_t min_key_code;
     xkb_keycode_t max_key_code;
@@ -155,10 +156,12 @@ ClearKeyNamesInfo(KeyNamesInfo *info)
 }
 
 static void
-InitKeyNamesInfo(KeyNamesInfo *info, struct xkb_context *ctx)
+InitKeyNamesInfo(KeyNamesInfo *info, struct xkb_context *ctx,
+                 unsigned int include_depth)
 {
     memset(info, 0, sizeof(*info));
     info->ctx = ctx;
+    info->include_depth = include_depth;
     info->min_key_code = XKB_KEYCODE_INVALID;
 #if XKB_KEYCODE_INVALID < XKB_KEYCODE_MAX
 #error "Hey, you can't be changing stuff like that."
@@ -339,7 +342,12 @@ HandleIncludeKeycodes(KeyNamesInfo *info, IncludeStmt *include)
 {
     KeyNamesInfo included;
 
-    InitKeyNamesInfo(&included, info->ctx);
+    if (ExceedsIncludeMaxDepth(info->ctx, info->include_depth)) {
+        info->errorCount += 10;
+        return false;
+    }
+
+    InitKeyNamesInfo(&included, info->ctx, 0 /* unused */);
     included.name = include->stmt;
     include->stmt = NULL;
 
@@ -354,7 +362,7 @@ HandleIncludeKeycodes(KeyNamesInfo *info, IncludeStmt *include)
             return false;
         }
 
-        InitKeyNamesInfo(&next_incl, info->ctx);
+        InitKeyNamesInfo(&next_incl, info->ctx, info->include_depth + 1);
 
         HandleKeycodesFile(&next_incl, file, MERGE_OVERRIDE);
 
@@ -662,7 +670,7 @@ CompileKeycodes(XkbFile *file, struct xkb_keymap *keymap,
 {
     KeyNamesInfo info;
 
-    InitKeyNamesInfo(&info, keymap->ctx);
+    InitKeyNamesInfo(&info, keymap->ctx, 0);
 
     HandleKeycodesFile(&info, file, merge);
     if (info.errorCount != 0)

src/xkbcomp/symbols.c

@@ -175,6 +175,7 @@ typedef struct {
 typedef struct {
     char *name;         /* e.g. pc+us+inet(evdev) */
     int errorCount;
+    unsigned int include_depth;
     enum merge_mode merge;
     xkb_layout_index_t explicit_group;
     darray(KeyInfo) keys;
@@ -191,10 +192,12 @@ typedef struct {
 
 static void
 InitSymbolsInfo(SymbolsInfo *info, const struct xkb_keymap *keymap,
+                unsigned int include_depth,
                 ActionsInfo *actions, const struct xkb_mod_set *mods)
 {
     memset(info, 0, sizeof(*info));
     info->ctx = keymap->ctx;
+    info->include_depth = include_depth;
     info->keymap = keymap;
     info->merge = MERGE_OVERRIDE;
     InitKeyInfo(keymap->ctx, &info->default_key);
@@ -569,7 +572,13 @@ HandleIncludeSymbols(SymbolsInfo *info, IncludeStmt *include)
 {
     SymbolsInfo included;
 
-    InitSymbolsInfo(&included, info->keymap, info->actions, &info->mods);
+    if (ExceedsIncludeMaxDepth(info->ctx, info->include_depth)) {
+        info->errorCount += 10;
+        return false;
+    }
+
+    InitSymbolsInfo(&included, info->keymap, 0 /* unused */,
+                    info->actions, &info->mods);
     included.name = include->stmt;
     include->stmt = NULL;
 
@@ -584,8 +593,8 @@ HandleIncludeSymbols(SymbolsInfo *info, IncludeStmt *include)
             return false;
         }
 
-        InitSymbolsInfo(&next_incl, info->keymap, info->actions,
-                        &included.mods);
+        InitSymbolsInfo(&next_incl, info->keymap, info->include_depth + 1,
+                        info->actions, &included.mods);
         if (stmt->modifier) {
             next_incl.explicit_group = atoi(stmt->modifier) - 1;
             if (next_incl.explicit_group >= XKB_MAX_GROUPS) {
@@ -1638,7 +1647,7 @@ CompileSymbols(XkbFile *file, struct xkb_keymap *keymap,
     if (!actions)
         return false;
 
-    InitSymbolsInfo(&info, keymap, actions, &keymap->mods);
+    InitSymbolsInfo(&info, keymap, 0, actions, &keymap->mods);
     info.default_key.merge = merge;
 
     HandleSymbolsFile(&info, file, merge);

src/xkbcomp/types.c

@@ -53,6 +53,7 @@ typedef struct {
 typedef struct {
     char *name;
     int errorCount;
+    unsigned int include_depth;
 
     darray(KeyTypeInfo) types;
     struct xkb_mod_set mods;
@@ -100,10 +101,12 @@ ReportTypeBadType(KeyTypesInfo *info, xkb_message_code_t code,
 
 static void
 InitKeyTypesInfo(KeyTypesInfo *info, struct xkb_context *ctx,
+                 unsigned int include_depth,
                  const struct xkb_mod_set *mods)
 {
     memset(info, 0, sizeof(*info));
     info->ctx = ctx;
+    info->include_depth = include_depth;
     info->mods = *mods;
 }
 
@@ -219,7 +222,12 @@ HandleIncludeKeyTypes(KeyTypesInfo *info, IncludeStmt *include)
 {
     KeyTypesInfo included;
 
-    InitKeyTypesInfo(&included, info->ctx, &info->mods);
+    if (ExceedsIncludeMaxDepth(info->ctx, info->include_depth)) {
+        info->errorCount += 10;
+        return false;
+    }
+
+    InitKeyTypesInfo(&included, info->ctx, 0 /* unused */, &info->mods);
     included.name = include->stmt;
     include->stmt = NULL;
 
@@ -234,7 +242,8 @@ HandleIncludeKeyTypes(KeyTypesInfo *info, IncludeStmt *include)
             return false;
         }
 
-        InitKeyTypesInfo(&next_incl, info->ctx, &included.mods);
+        InitKeyTypesInfo(&next_incl, info->ctx, info->include_depth + 1,
+                         &included.mods);
 
         HandleKeyTypesFile(&next_incl, file, stmt->merge);
 
@@ -754,7 +763,7 @@ CompileKeyTypes(XkbFile *file, struct xkb_keymap *keymap,
 {
     KeyTypesInfo info;
 
-    InitKeyTypesInfo(&info, keymap->ctx, &keymap->mods);
+    InitKeyTypesInfo(&info, keymap->ctx, 0, &keymap->mods);
 
     HandleKeyTypesFile(&info, file, merge);
     if (info.errorCount != 0)