Merge tag 'kconfig-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kconfig updates from Masahiro Yamada:

 - error out if a user specifies a directory instead of a file from
   "Save" menu of GUI interfaces

 - do not overwrite .config if there is no change in the configuration

 - create parent directories as needed when a user specifies a new file
   path from "Save" menu of menuconfig/nconfig

 - fix potential buffer overflow

 - some trivial cleanups

* tag 'kconfig-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: make conf_get_autoconfig_name() static
  kconfig: use snprintf for formatting pathnames
  kconfig: remove useless NULL pointer check in conf_write_dep()
  kconfig: make parent directories for the saved .config as needed
  kconfig: do not write .config if the content is the same
  kconfig: do not accept a directory for configuration output
  kconfig: remove trailing whitespaces
  kconfig: Make nconf-cfg.sh executable

8 files changed, 89 insertions, 45 deletions

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 08ba146a83c5..492ac3410147 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
  */
 
+#include <sys/mman.h>
 #include <sys/stat.h>
 #include <ctype.h>
 #include <errno.h>
@@ -36,6 +37,52 @@ static bool is_dir(const char *path)
         return S_ISDIR(st.st_mode);
 }
 
+/* return true if the given two files are the same, false otherwise */
+static bool is_same(const char *file1, const char *file2)
+{
+        int fd1, fd2;
+        struct stat st1, st2;
+        void *map1, *map2;
+        bool ret = false;
+
+        fd1 = open(file1, O_RDONLY);
+        if (fd1 < 0)
+                return ret;
+
+        fd2 = open(file2, O_RDONLY);
+        if (fd2 < 0)
+                goto close1;
+
+        ret = fstat(fd1, &st1);
+        if (ret)
+                goto close2;
+        ret = fstat(fd2, &st2);
+        if (ret)
+                goto close2;
+
+        if (st1.st_size != st2.st_size)
+                goto close2;
+
+        map1 = mmap(NULL, st1.st_size, PROT_READ, MAP_PRIVATE, fd1, 0);
+        if (map1 == MAP_FAILED)
+                goto close2;
+
+        map2 = mmap(NULL, st2.st_size, PROT_READ, MAP_PRIVATE, fd2, 0);
+        if (map2 == MAP_FAILED)
+                goto close2;
+
+        if (bcmp(map1, map2, st1.st_size))
+                goto close2;
+
+        ret = true;
+close2:
+        close(fd2);
+close1:
+        close(fd1);
+
+        return ret;
+}
+
 /*
  * Create the parent directory of the given path.
  *
@@ -179,7 +226,7 @@ const char *conf_get_configname(void)
         return name ? name : ".config";
 }
 
-const char *conf_get_autoconfig_name(void)
+static const char *conf_get_autoconfig_name(void)
 {
         char *name = getenv("KCONFIG_AUTOCONFIG");
 
@@ -194,7 +241,7 @@ char *conf_get_default_confname(void)
         name = expand_string(conf_defname);
         env = getenv(SRCTREE);
         if (env) {
-                sprintf(fullname, "%s/%s", env, name);
+                snprintf(fullname, sizeof(fullname), "%s/%s", env, name);
                 if (is_present(fullname))
                         return fullname;
         }
@@ -817,40 +864,34 @@ int conf_write(const char *name)
         FILE *out;
         struct symbol *sym;
         struct menu *menu;
-        const char *basename;
         const char *str;
-        char dirname[PATH_MAX+1], tmpname[PATH_MAX+22], newname[PATH_MAX+8];
+        char tmpname[PATH_MAX + 1], oldname[PATH_MAX + 1];
         char *env;
 
-        dirname[0] = 0;
-        if (name && name[0]) {
-                char *slash;
-
-                if (is_dir(name)) {
-                        strcpy(dirname, name);
-                        strcat(dirname, "/");
-                        basename = conf_get_configname();
-                } else if ((slash = strrchr(name, '/'))) {
-                        int size = slash - name + 1;
-                        memcpy(dirname, name, size);
-                        dirname[size] = 0;
-                        if (slash[1])
-                                basename = slash + 1;
-                        else
-                                basename = conf_get_configname();
-                } else
-                        basename = name;
-        } else
-                basename = conf_get_configname();
-
-        sprintf(newname, "%s%s", dirname, basename);
+        if (!name)
+                name = conf_get_configname();
+
+        if (!*name) {
+                fprintf(stderr, "config name is empty\n");
+                return -1;
+        }
+
+        if (is_dir(name)) {
+                fprintf(stderr, "%s: Is a directory\n", name);
+                return -1;
+        }
+
+        if (make_parent_dir(name))
+                return -1;
+
         env = getenv("KCONFIG_OVERWRITECONFIG");
-        if (!env || !*env) {
-                sprintf(tmpname, "%s.tmpconfig.%d", dirname, (int)getpid());
-                out = fopen(tmpname, "w");
-        } else {
+        if (env && *env) {
                 *tmpname = 0;
-                out = fopen(newname, "w");
+                out = fopen(name, "w");
+        } else {
+                snprintf(tmpname, sizeof(tmpname), "%s.%d.tmp",
+                         name, (int)getpid());
+                out = fopen(tmpname, "w");
         }
         if (!out)
                 return 1;
@@ -897,14 +938,20 @@ next:
         fclose(out);
 
         if (*tmpname) {
-                strcat(dirname, basename);
-                strcat(dirname, ".old");
-                rename(newname, dirname);
-                if (rename(tmpname, newname))
+                if (is_same(name, tmpname)) {
+                        conf_message("No change to %s", name);
+                        unlink(tmpname);
+                        sym_set_change_count(0);
+                        return 0;
+                }
+
+                snprintf(oldname, sizeof(oldname), "%s.old", name);
+                rename(name, oldname);
+                if (rename(tmpname, name))
                         return 1;
         }
 
-        conf_message("configuration written to %s", newname);
+        conf_message("configuration written to %s", name);
 
         sym_set_change_count(0);
 
@@ -917,8 +964,6 @@ static int conf_write_dep(const char *name)
         struct file *file;
         FILE *out;
 
-        if (!name)
-                name = ".kconfig.d";
         out = fopen("..config.tmp", "w");
         if (!out)
                 return 1;
diff --git a/scripts/kconfig/gconf.c b/scripts/kconfig/gconf.c
index 5d4ecf309ee4..e36b342f1065 100644
--- a/scripts/kconfig/gconf.c
+++ b/scripts/kconfig/gconf.c
@@ -638,7 +638,7 @@ on_set_option_mode3_activate(GtkMenuItem *menuitem, gpointer user_data)
 void on_introduction1_activate(GtkMenuItem * menuitem, gpointer user_data)
 {
         GtkWidget *dialog;
-        const gchar *intro_text = 
+        const gchar *intro_text =
             "Welcome to gkc, the GTK+ graphical configuration tool\n"
             "For each option, a blank box indicates the feature is disabled, a\n"
             "check indicates it is enabled, and a dot indicates that it is to\n"
diff --git a/scripts/kconfig/lexer.l b/scripts/kconfig/lexer.l
index c9df1c8b9824..6354c905b006 100644
--- a/scripts/kconfig/lexer.l
+++ b/scripts/kconfig/lexer.l
@@ -378,7 +378,8 @@ FILE *zconf_fopen(const char *name)
         if (!f && name != NULL && name[0] != '/') {
                 env = getenv(SRCTREE);
                 if (env) {
-                        sprintf(fullname, "%s/%s", env, name);
+                        snprintf(fullname, sizeof(fullname),
+                                 "%s/%s", env, name);
                         f = fopen(fullname, "r");
                 }
         }
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index d871539e4b45..cbc7658ee27d 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -49,7 +49,6 @@ const char *zconf_curname(void);
 
 /* confdata.c */
 const char *conf_get_configname(void);
-const char *conf_get_autoconfig_name(void);
 char *conf_get_default_confname(void);
 void sym_set_change_count(int count);
 void sym_add_change_count(int count);
diff --git a/scripts/kconfig/lxdialog/BIG.FAT.WARNING b/scripts/kconfig/lxdialog/BIG.FAT.WARNING
index a8999d82bdb3..7cb5a7ec93d2 100644
--- a/scripts/kconfig/lxdialog/BIG.FAT.WARNING
+++ b/scripts/kconfig/lxdialog/BIG.FAT.WARNING
@@ -1,4 +1,4 @@
 This is NOT the official version of dialog.  This version has been
 significantly modified from the original.  It is for use by the Linux
-kernel configuration script.  Please do not bother Savio Lam with 
+kernel configuration script.  Please do not bother Savio Lam with
 questions about this program.
diff --git a/scripts/kconfig/mconf.c b/scripts/kconfig/mconf.c
index 5f8c82a4cb08..694091f3ef9d 100644
--- a/scripts/kconfig/mconf.c
+++ b/scripts/kconfig/mconf.c
@@ -936,7 +936,7 @@ static void conf_save(void)
                                 set_config_filename(dialog_input_result);
                                 return;
                         }
-                        show_textbox(NULL, "Can't create file!  Probably a nonexistent directory.", 5, 60);
+                        show_textbox(NULL, "Can't create file!", 5, 60);
                         break;
                 case 1:
                         show_helptext("Save Alternate Configuration", save_config_help);
diff --git a/scripts/kconfig/nconf-cfg.sh b/scripts/kconfig/nconf-cfg.sh
index 001559ef0a60..001559ef0a60 100644..100755
--- a/scripts/kconfig/nconf-cfg.sh
+++ b/scripts/kconfig/nconf-cfg.sh
diff --git a/scripts/kconfig/nconf.c b/scripts/kconfig/nconf.c
index ac92c0ded6c5..cbafe3bf082e 100644
--- a/scripts/kconfig/nconf.c
+++ b/scripts/kconfig/nconf.c
@@ -1438,8 +1438,7 @@ static void conf_save(void)
                                 set_config_filename(dialog_input_result);
                                 return;
                         }
-                        btn_dialog(main_window, "Can't create file! "
-                                "Probably a nonexistent directory.",
+                        btn_dialog(main_window, "Can't create file!",
                                 1, "<OK>");
                         break;
                 case 1: