fix(security): prevent CWE-134 format string injection

- add "%s" to unsafe cons_show/log_*/win_println calls
- add check-cwe134.sh static analysis script
- integrate security check into CI pipeline

Closes #85

.github/workflows/ci-code.yml

@@ -50,6 +50,9 @@ jobs:
         run: |
           grep -P 'auto_(char|gchar|gcharv|guchar|jid|sqlite|gfd|FILE)[\w *]*;$' -r src && exit -1 || true
 
+      - name: Check CWE-134 format string vulnerabilities
+        run: ./check-cwe134.sh
+
       - name: Install clang-format
         run: |
           sudo apt-get update

check-cwe134.sh

@@ -0,0 +1,69 @@
+#!/bin/bash
+# check-cwe134.sh - Static analysis for CWE-134 format string vulnerabilities
+#
+# This script detects potentially unsafe usage of format string functions
+# where user-controlled data may be passed without "%s" wrapper.
+#
+# Usage: ./check-cwe134.sh [directory]
+
+set -e
+
+DIR="${1:-src}"
+
+echo "=== CWE-134 Format String Vulnerability Check ==="
+echo "Scanning: $DIR"
+echo ""
+
+# Functions that accept format strings
+FORMAT_FUNCS="cons_show|cons_debug|cons_show_error|log_info|log_error|log_warning|log_debug|win_println|win_print"
+
+ERRORS=0
+
+echo "Checking for unsafe format string usage..."
+echo ""
+
+# Pattern 1: function call with single variable argument (no format string)
+# Example: cons_show(variable);  - BAD
+# Example: cons_show("%s", variable);  - OK
+# Matches: func(identifier) or func(identifier->member) or func(identifier[index])
+RESULTS=$(grep -rn --include="*.c" -P "($FORMAT_FUNCS)\s*\(\s*[a-zA-Z_][a-zA-Z0-9_]*(\s*->\s*\w+|\s*\[\s*\w+\s*\])?\s*\)\s*;" "$DIR" 2>/dev/null || true)
+
+# Filter out function definitions, declarations, and safe api_* wrappers
+RESULTS=$(echo "$RESULTS" | grep -v "const char\|void \|^[^:]*:[0-9]*:[a-z_]*(\|api_cons_show\|api_log_" || true)
+
+if [ -n "$RESULTS" ]; then
+    echo "❌ POTENTIAL CWE-134 VULNERABILITIES FOUND:"
+    echo ""
+    echo "$RESULTS"
+    echo ""
+    ERRORS=$(echo "$RESULTS" | wc -l)
+else
+    echo "✅ No obvious CWE-134 issues found."
+fi
+
+# Additional check: GString->str passed directly (not as %s argument)
+echo ""
+echo "Checking for GString->str passed to format functions..."
+
+GSTRING_RESULTS=$(grep -rn --include="*.c" -P "($FORMAT_FUNCS)\s*\([^)]*->str\s*\)" "$DIR" 2>/dev/null | grep -v '"%s"' || true)
+
+if [ -n "$GSTRING_RESULTS" ]; then
+    echo "⚠️  GString->str passed without \"%s\" (review manually):"
+    echo ""
+    echo "$GSTRING_RESULTS"
+    echo ""
+fi
+
+echo ""
+echo "=== Summary ==="
+echo "Critical issues: $ERRORS"
+
+if [ "$ERRORS" -gt 0 ]; then
+    echo ""
+    echo "Fix by adding \"%s\" format specifier:"
+    echo "  BAD:  cons_show(variable);"
+    echo "  GOOD: cons_show(\"%s\", variable);"
+    exit 1
+fi
+
+exit 0

src/command/cmd_funcs.c

@@ -4970,8 +4970,8 @@ cmd_sendfile(ProfWin* window, const char* const command, gchar** args)
         alt_scheme = OMEMO_AESGCM_URL_SCHEME;
         alt_fragment = _add_omemo_stream(&fd, &fh, &err);
         if (err != NULL) {
-            cons_show_error(err);
-            win_println(window, THEME_ERROR, "-", err);
+            cons_show_error("%s", err);
+            win_println(window, THEME_ERROR, "-", "%s", err);
             goto out;
         }
 #endif

src/common.c

@@ -143,7 +143,7 @@ auto_close_gfd(gint* fd)
         return;
 
     if (close(*fd) == EOF)
-        log_error(g_strerror(errno));
+        log_error("%s", g_strerror(errno));
 }
 
 /**
@@ -158,7 +158,7 @@ auto_close_FILE(FILE** fd)
         return;
 
     if (fclose(*fd) == EOF)
-        log_error(g_strerror(errno));
+        log_error("%s", g_strerror(errno));
 }
 
 static gboolean

src/plugins/python_plugins.c

@@ -887,8 +887,8 @@ _python_undefined_error(ProfPlugin* plugin, char* hook, char* type)
     g_string_append(err_msg, hook);
     g_string_append(err_msg, "(): return value undefined, expected ");
     g_string_append(err_msg, type);
-    log_error(err_msg->str);
-    cons_show_error(err_msg->str);
+    log_error("%s", err_msg->str);
+    cons_show_error("%s", err_msg->str);
     g_string_free(err_msg, TRUE);
 }
 
@@ -901,8 +901,8 @@ _python_type_error(ProfPlugin* plugin, char* hook, char* type)
     g_string_append(err_msg, hook);
     g_string_append(err_msg, "(): incorrect return type, expected ");
     g_string_append(err_msg, type);
-    log_error(err_msg->str);
-    cons_show_error(err_msg->str);
+    log_error("%s", err_msg->str);
+    cons_show_error("%s", err_msg->str);
     g_string_free(err_msg, TRUE);
 }
 

src/profanity.c

@@ -135,7 +135,7 @@ prof_run(gchar* log_level, gchar* account_name, gchar* config_file, gchar* log_f
                          */
                         min_runtime += waittime;
                     } else {
-                        log_error(err_msg);
+                        log_error("%s", err_msg);
                         g_free(err_msg);
                         commands = NULL;
                     }
@@ -245,7 +245,7 @@ _init(char* log_level, char* config_file, char* log_file, char* theme_name)
     if (prof_log_level == PROF_LEVEL_DEBUG) {
         ProfWin* console = wins_get_console();
         win_println(console, THEME_DEFAULT, "-", "Debug mode enabled! Logging to: ");
-        win_println(console, THEME_DEFAULT, "-", get_log_file_location());
+        win_println(console, THEME_DEFAULT, "-", "%s", get_log_file_location());
     }
     session_init();
     cmd_init();

src/tools/http_upload.c

@@ -311,7 +311,7 @@ http_file_put(void* userdata)
             }
             win_update_entry_message(upload->window, upload->put_url, err_msg);
         }
-        cons_show_error(err_msg);
+        cons_show_error("%s", err_msg);
     } else {
         if (!upload->cancel) {
             auto_gchar gchar* status_msg = g_strdup_printf("Uploading '%s': 100%%", upload->filename);
@@ -327,7 +327,7 @@ http_file_put(void* userdata)
                 if (!fail_msg) {
                     fail_msg = g_strdup(FALLBACK_MSG);
                 }
-                cons_show_error(fail_msg);
+                cons_show_error("%s", fail_msg);
             } else {
                 switch (upload->window->type) {
                 case WIN_CHAT:

src/ui/console.c

@@ -938,7 +938,7 @@ cons_show_account_list(gchar** accounts)
                 theme_item_t presence_colour = theme_main_presence_attrs(string_from_resource_presence(presence));
                 win_println(console, presence_colour, "-", "%s", accounts[i]);
             } else {
-                cons_show(accounts[i]);
+                cons_show("%s", accounts[i]);
             }
         }
         cons_show("");

src/ui/core.c

@@ -445,7 +445,7 @@ ui_handle_error(const char* const err_msg)
     GString* msg = g_string_new("");
     g_string_printf(msg, "Error %s", err_msg);
 
-    cons_show_error(msg->str);
+    cons_show_error("%s", msg->str);
 
     g_string_free(msg, TRUE);
 }

src/ui/window.c

@@ -2297,7 +2297,7 @@ void
 win_handle_command_exec_result_note(ProfWin* window, const char* const type, const char* const value)
 {
     assert(window != NULL);
-    win_println(window, THEME_DEFAULT, "!", value);
+    win_println(window, THEME_DEFAULT, "!", "%s", value);
 }
 
 void

src/xmpp/message.c

@@ -868,7 +868,7 @@ _handle_error(xmpp_stanza_t* const stanza)
     g_string_append(log_msg, " error=");
     g_string_append(log_msg, err_msg);
 
-    log_info(log_msg->str);
+    log_info("%s", log_msg->str);
 
     g_string_free(log_msg, TRUE);
 

src/xmpp/presence.c

@@ -455,7 +455,7 @@ _presence_error_handler(xmpp_stanza_t* const stanza)
     g_string_append(log_msg, " error=");
     g_string_append(log_msg, err_msg);
 
-    log_info(log_msg->str);
+    log_info("%s", log_msg->str);
 
     g_string_free(log_msg, TRUE);