[hackers] [surf] Check $HOME and home dir of $USER before getpwuid()->pw_dir || Dmitry Bogatov

From: <git_AT_suckless.org>
Date: Tue, 5 Jul 2016 13:02:32 +0200 (CEST)

commit cee8f0186ce3277add9b6a8ac07588be40f0f080
Author: Dmitry Bogatov <KAction_AT_gnu.org>
AuthorDate: Sun May 29 11:56:51 2016 +0200
Commit: Quentin Rameau <quinq_AT_fifth.space>
CommitDate: Tue Jul 5 13:01:56 2016 +0200

    Check $HOME and home dir of $USER before getpwuid()->pw_dir
    
    getpwnam(3) recommends to use $HOME instead of getpwuid()->pw_dir,
    as it allows users to point programs to a different path.
    
    Using getpwuid() also breaks namespaces-related use cases,
    like `unshare -r`.
    
    Patch was submitted by Dmitry Bogatov on the Debian bug tracker:
    https://bugs.debian.org/825397
    
    Signed-off-by: Christoph Lohmann <20h_AT_r-36.net>

diff --git a/surf.c b/surf.c
index 3d6cc11..105b28e 100644
--- a/surf.c
+++ b/surf.c
_AT_@ -350,29 +350,58 @@ buildfile(const char *path)
         return fpath;
 }
 
+static const char*
+get_user_homedir(const char *user) {
+ struct passwd *pw = getpwnam(user);
+ if (!pw) {
+ die("Can't get user `%s' home directory.\n", user);
+ }
+ return pw->pw_dir;
+}
+
+static const char*
+get_current_user_homedir() {
+ const char *homedir;
+ const char *user;
+ struct passwd *pw;
+
+ homedir = getenv("HOME");
+ if (homedir) {
+ return homedir;
+ }
+
+ user = getenv("USER");
+ if (user) {
+ return get_user_homedir(user);
+ }
+
+ pw = getpwuid(getuid());
+ if (!pw) {
+ die("Can't get current user home directory\n");
+ }
+ return pw->pw_dir;
+}
+
 char *
 buildpath(const char *path)
 {
- struct passwd *pw;
         char *apath, *name, *p, *fpath;
 
         if (path[0] == '~') {
+ const char *homedir;
                 if (path[1] == '/' || path[1] == '\0') {
                         p = (char *)&path[1];
- pw = getpwuid(getuid());
+ homedir = get_current_user_homedir();
                 } else {
                         if ((p = strchr(path, '/')))
                                 name = g_strndup(&path[1], --p - path);
                         else
                                 name = g_strdup(&path[1]);
 
- if (!(pw = getpwnam(name))) {
- die("Can't get user %s home directory: %s.\n",
- name, path);
- }
+ homedir = get_user_homedir(name);
                         g_free(name);
                 }
- apath = g_build_filename(pw->pw_dir, p, NULL);
+ apath = g_build_filename(homedir, p, NULL);
         } else {
                 apath = g_strdup(path);
         }
Received on Tue Jul 05 2016 - 13:02:32 CEST