commit e12af2adb0919d0de6d6ba44462d9255f63fca5b Author: Nick Mathewson nickm@torproject.org Date: Wed May 14 13:50:43 2014 -0400

Add a pair of wrapper functions: tor_getpwnam() and tor_getpwuid()

We'll use these to deal with being unable to access the user DB after we install the sandbox, to fix bug 11946. --- src/common/compat.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++ src/common/compat.h | 5 ++++ src/or/main.c | 3 ++ 3 files changed, 91 insertions(+)

diff --git a/src/common/compat.c b/src/common/compat.c index 7a444df..9f31cce 100644 --- a/src/common/compat.c +++ b/src/common/compat.c @@ -1702,6 +1702,89 @@ log_credential_status(void) } #endif

+#ifndef _WIN32 +static struct passwd *passwd_cached = NULL; + +static struct passwd * +tor_passwd_dup(const struct passwd *pw) +{ + struct passwd *new_pw = tor_malloc_zero(sizeof(struct passwd)); + if (pw->pw_name) + new_pw->pw_name = tor_strdup(pw->pw_name); + if (pw->pw_dir) + new_pw->pw_dir = tor_strdup(pw->pw_dir); + new_pw->pw_uid = pw->pw_uid; + new_pw->pw_gid = pw->pw_gid; + + return new_pw; +} + +static void +tor_passwd_free(struct passwd *pw) +{ + if (!pw) + return; + + tor_free(pw->pw_name); + tor_free(pw->pw_dir); + tor_free(pw); +} + +/** Wrapper around getpwnam() that caches result. Used so that we don't need + * to give the sandbox access to /etc/passwd. */ +const struct passwd * +tor_getpwnam(const char *username) +{ + struct passwd *pw; + + if (username == NULL) { + tor_passwd_free(passwd_cached); + passwd_cached = NULL; + return NULL; + } + + if ((pw = getpwnam(username))) { + tor_passwd_free(passwd_cached); + passwd_cached = tor_passwd_dup(pw); + log_notice(LD_GENERAL, "Caching new entry %s for %s", + passwd_cached->pw_name, username); + return pw; + } + + /* Lookup failed */ + if (! passwd_cached || ! passwd_cached->pw_name) + return NULL; + + if (! strcmp(username, passwd_cached->pw_name)) + return passwd_cached; + + return NULL; +} + +/** Wrapper around getpwnam() that can use cached result from + * tor_getpwnam(). Used so that we don't need to give the sandbox access to + * /etc/passwd. */ +const struct passwd * +tor_getpwuid(uid_t uid) +{ + struct passwd *pw; + + if ((pw = getpwuid(uid))) { + return pw; + } + + /* Lookup failed */ + if (! passwd_cached) + return NULL; + + if (uid == passwd_cached->pw_uid) + return passwd_cached; + + return NULL; +} +#endif + + /** Call setuid and setgid to run as <b>user</b> and switch to their * primary group. Return 0 on success. On failure, log and return -1. */ diff --git a/src/common/compat.h b/src/common/compat.h index 314b1aa..683c4d0 100644 --- a/src/common/compat.h +++ b/src/common/compat.h @@ -633,6 +633,11 @@ int switch_id(const char *user); char *get_user_homedir(const char *username); #endif

+#ifndef _WIN32 +const struct passwd *tor_getpwnam(const char *username); +const struct passwd *tor_getpwuid(uid_t uid); +#endif + int get_parent_directory(char *fname); char *make_path_absolute(char *fname);

diff --git a/src/or/main.c b/src/or/main.c index 5532026..a2c5743 100644 --- a/src/or/main.c +++ b/src/or/main.c @@ -2548,6 +2548,9 @@ tor_free_all(int postfork) free_cell_pool(); if (!postfork) { tor_tls_free_all(); +#ifndef _WIN32 + tor_getpwnam(NULL); +#endif } /* stuff in main.c */