commit 9b4ac986cbe8867c24c8e77654a4b7e75f870738 Author: Nick Mathewson nickm@torproject.org Date: Wed May 14 13:53:14 2014 -0400
Use tor_getpw{nam,uid} wrappers to fix bug 11946
When running with User set, we frequently try to look up our information in the user database (e.g., /etc/passwd). The seccomp2 sandbox setup doesn't let us open /etc/passwd, and probably shouldn't.
To fix this, we have a pair of wrappers for getpwnam and getpwuid. When a real call to getpwnam or getpwuid fails, they fall back to a cached value, if the uid/gid matches.
(Granting access to /etc/passwd isn't possible with the way we handle opening files through the sandbox. It's not desirable either.) --- changes/bug11946 | 5 +++++ src/common/compat.c | 8 ++++---- src/common/util.c | 10 +++++----- src/or/connection.c | 4 ++-- src/or/control.c | 2 +- 5 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/changes/bug11946 b/changes/bug11946 new file mode 100644 index 0000000..9ea4831 --- /dev/null +++ b/changes/bug11946 @@ -0,0 +1,5 @@ + o Minor bugfixes (sandbox): + + - Handle failures in getpwnam()/getpwuid() when running with the + User option set and the Linux syscall sandbox enabled. Fixes bug + 11946; bugfix on 0.2.5.1-alpha. diff --git a/src/common/compat.c b/src/common/compat.c index 9f31cce..65446b5 100644 --- a/src/common/compat.c +++ b/src/common/compat.c @@ -1792,7 +1792,7 @@ int switch_id(const char *user) { #ifndef _WIN32 - struct passwd *pw = NULL; + const struct passwd *pw = NULL; uid_t old_uid; gid_t old_gid; static int have_already_switched_id = 0; @@ -1813,7 +1813,7 @@ switch_id(const char *user) old_gid = getgid();
/* Lookup the user and group information, if we have a problem, bail out. */ - pw = getpwnam(user); + pw = tor_getpwnam(user); if (pw == NULL) { log_warn(LD_CONFIG, "Error setting configured user: %s not found", user); return -1; @@ -1984,10 +1984,10 @@ tor_disable_debugger_attach(void) char * get_user_homedir(const char *username) { - struct passwd *pw; + const struct passwd *pw; tor_assert(username);
- if (!(pw = getpwnam(username))) { + if (!(pw = tor_getpwnam(username))) { log_err(LD_CONFIG,"User "%s" not found.", username); return NULL; } diff --git a/src/common/util.c b/src/common/util.c index d573b56..d457ba9 100644 --- a/src/common/util.c +++ b/src/common/util.c @@ -1871,7 +1871,7 @@ check_private_dir(const char *dirname, cpd_check_t check, char *f; #ifndef _WIN32 int mask; - struct passwd *pw = NULL; + const struct passwd *pw = NULL; uid_t running_uid; gid_t running_gid; #else @@ -1918,7 +1918,7 @@ check_private_dir(const char *dirname, cpd_check_t check, if (effective_user) { /* Look up the user and group information. * If we have a problem, bail out. */ - pw = getpwnam(effective_user); + pw = tor_getpwnam(effective_user); if (pw == NULL) { log_warn(LD_CONFIG, "Error setting configured user: %s not found", effective_user); @@ -1932,13 +1932,13 @@ check_private_dir(const char *dirname, cpd_check_t check, }
if (st.st_uid != running_uid) { - struct passwd *pw = NULL; + const struct passwd *pw = NULL; char *process_ownername = NULL;
- pw = getpwuid(running_uid); + pw = tor_getpwuid(running_uid); process_ownername = pw ? tor_strdup(pw->pw_name) : tor_strdup("<unknown>");
- pw = getpwuid(st.st_uid); + pw = tor_getpwuid(st.st_uid);
log_warn(LD_FS, "%s is not owned by this user (%s, %d) but by " "%s (%d). Perhaps you are running Tor as the wrong user?", diff --git a/src/or/connection.c b/src/or/connection.c index 3cc4e09..cef9172 100644 --- a/src/or/connection.c +++ b/src/or/connection.c @@ -1017,7 +1017,7 @@ connection_listener_new(const struct sockaddr *listensockaddr, tor_socket_t s = TOR_INVALID_SOCKET; /* the socket we're going to make */ or_options_t const *options = get_options(); #if defined(HAVE_PWD_H) && defined(HAVE_SYS_UN_H) - struct passwd *pw = NULL; + const struct passwd *pw = NULL; #endif uint16_t usePort = 0, gotPort = 0; int start_reading = 0; @@ -1157,7 +1157,7 @@ connection_listener_new(const struct sockaddr *listensockaddr, } #ifdef HAVE_PWD_H if (options->User) { - pw = getpwnam(options->User); + pw = tor_getpwnam(options->User); if (pw == NULL) { log_warn(LD_NET,"Unable to chown() %s socket: user %s not found.", address, options->User); diff --git a/src/or/control.c b/src/or/control.c index d571900..2865d78 100755 --- a/src/or/control.c +++ b/src/or/control.c @@ -1492,7 +1492,7 @@ getinfo_helper_misc(control_connection_t *conn, const char *question, *answer = tor_strdup(""); #else int myUid = geteuid(); - struct passwd *myPwEntry = getpwuid(myUid); + const struct passwd *myPwEntry = tor_getpwuid(myUid);
if (myPwEntry) { *answer = tor_strdup(myPwEntry->pw_name);