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journald: use SCM_SECURITY to race-freely determine peer SELinux label

Browse Source 
https://bugzilla.redhat.com/show_bug.cgi?id=798760
This commit is contained in:
Lennart Poettering
2012-03-13 02:29:10 +01:00
parent 54ecda32c6
commit 7f2c63cbf4
1 changed files with 80 additions and 26 deletions
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src/journal/journald.c
+80 -26
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@@ -45,6 +45,7 @@
#include "conf-parser.h"
#include "journald.h"
#include "virt.h"
#include "missing.h"
#ifdef HAVE_ACL
#include <sys/acl.h>
@@ -87,6 +88,9 @@ struct StdoutStream {
int fd;
struct ucred ucred;
#ifdef HAVE_SELINUX
security_context_t security_context;
#endif
char *identifier;
int priority;
@@ -430,10 +434,12 @@ static char *shortened_cgroup_path(pid_t pid) {
return path;
}
static void dispatch_message_real(Server *s,
struct iovec *iovec, unsigned n, unsigned m,
struct ucred *ucred,
struct timeval *tv) {
static void dispatch_message_real(
Server *s,
struct iovec *iovec, unsigned n, unsigned m,
struct ucred *ucred,
struct timeval *tv,
const char *label, size_t label_len) {
char *pid = NULL, *uid = NULL, *gid = NULL,
*source_time = NULL, *boot_id = NULL, *machine_id = NULL,
@@ -458,9 +464,6 @@ static void dispatch_message_real(Server *s,
if (ucred) {
uint32_t audit;
uid_t owner;
#ifdef HAVE_SELINUX
security_context_t con;
#endif
realuid = ucred->uid;
@@ -540,12 +543,24 @@ static void dispatch_message_real(Server *s,
IOVEC_SET_STRING(iovec[n++], owner_uid);
#ifdef HAVE_SELINUX
if (getpidcon(ucred->pid, &con) >= 0) {
selinux_context = strappend("_SELINUX_CONTEXT=", con);
if (selinux_context)
if (label) {
selinux_context = malloc(sizeof("_SELINUX_CONTEXT=") + label_len);
if (selinux_context) {
memcpy(selinux_context, "_SELINUX_CONTEXT=", sizeof("_SELINUX_CONTEXT=")-1);
memcpy(selinux_context+sizeof("_SELINUX_CONTEXT=")-1, label, label_len);
selinux_context[sizeof("_SELINUX_CONTEXT=")-1+label_len] = 0;
IOVEC_SET_STRING(iovec[n++], selinux_context);
}
} else {
security_context_t con;
freecon(con);
if (getpidcon(ucred->pid, &con) >= 0) {
selinux_context = strappend("_SELINUX_CONTEXT=", con);
if (selinux_context)
IOVEC_SET_STRING(iovec[n++], selinux_context);
freecon(con);
}
}
#endif
}
@@ -652,13 +667,14 @@ static void driver_message(Server *s, sd_id128_t message_id, const char *format,
ucred.uid = getuid();
ucred.gid = getgid();
dispatch_message_real(s, iovec, n, ELEMENTSOF(iovec), &ucred, NULL);
dispatch_message_real(s, iovec, n, ELEMENTSOF(iovec), &ucred, NULL, NULL, 0);
}
static void dispatch_message(Server *s,
struct iovec *iovec, unsigned n, unsigned m,
struct ucred *ucred,
struct timeval *tv,
const char *label, size_t label_len,
int priority) {
int rl;
char *path = NULL, *c;
@@ -706,7 +722,7 @@ static void dispatch_message(Server *s,
free(path);
finish:
dispatch_message_real(s, iovec, n, m, ucred, tv);
dispatch_message_real(s, iovec, n, m, ucred, tv, label, label_len);
}
static void forward_syslog_iovec(Server *s, const struct iovec *iovec, unsigned n_iovec, struct ucred *ucred, struct timeval *tv) {
@@ -1006,7 +1022,7 @@ static void read_identifier(const char **buf, char **identifier, char **pid) {
*buf += strspn(*buf, WHITESPACE);
}
static void process_syslog_message(Server *s, const char *buf, struct ucred *ucred, struct timeval *tv) {
static void process_syslog_message(Server *s, const char *buf, struct ucred *ucred, struct timeval *tv, const char *label, size_t label_len) {
char *message = NULL, *syslog_priority = NULL, *syslog_facility = NULL, *syslog_identifier = NULL, *syslog_pid = NULL;
struct iovec iovec[N_IOVEC_META_FIELDS + 6];
unsigned n = 0;
@@ -1054,7 +1070,7 @@ static void process_syslog_message(Server *s, const char *buf, struct ucred *ucr
if (message)
IOVEC_SET_STRING(iovec[n++], message);
dispatch_message(s, iovec, n, ELEMENTSOF(iovec), ucred, tv, priority);
dispatch_message(s, iovec, n, ELEMENTSOF(iovec), ucred, tv, label, label_len, priority);
free(message);
free(identifier);
@@ -1099,7 +1115,13 @@ static bool valid_user_field(const char *p, size_t l) {
return true;
}
static void process_native_message(Server *s, const void *buffer, size_t buffer_size, struct ucred *ucred, struct timeval *tv) {
static void process_native_message(
Server *s,
const void *buffer, size_t buffer_size,
struct ucred *ucred,
struct timeval *tv,
const char *label, size_t label_len) {
struct iovec *iovec = NULL;
unsigned n = 0, m = 0, j, tn = (unsigned) -1;
const char *p;
@@ -1126,7 +1148,7 @@ static void process_native_message(Server *s, const void *buffer, size_t buffer_
if (e == p) {
/* Entry separator */
dispatch_message(s, iovec, n, m, ucred, tv, priority);
dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, priority);
n = 0;
priority = LOG_INFO;
@@ -1275,7 +1297,7 @@ static void process_native_message(Server *s, const void *buffer, size_t buffer_
forward_console(s, identifier, message, ucred);
}
dispatch_message(s, iovec, n, m, ucred, tv, priority);
dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, priority);
finish:
for (j = 0; j < n; j++) {
@@ -1291,7 +1313,13 @@ finish:
free(message);
}
static void process_native_file(Server *s, int fd, struct ucred *ucred, struct timeval *tv) {
static void process_native_file(
Server *s,
int fd,
struct ucred *ucred,
struct timeval *tv,
const char *label, size_t label_len) {
struct stat st;
void *p;
ssize_t n;
@@ -1332,7 +1360,7 @@ static void process_native_file(Server *s, int fd, struct ucred *ucred, struct t
if (n < 0)
log_error("Failed to read file, ignoring: %s", strerror(-n));
else if (n > 0)
process_native_message(s, p, n, ucred, tv);
process_native_message(s, p, n, ucred, tv, label, label_len);
free(p);
}
@@ -1342,6 +1370,8 @@ static int stdout_stream_log(StdoutStream *s, const char *p) {
char *message = NULL, *syslog_priority = NULL, *syslog_facility = NULL, *syslog_identifier = NULL;
unsigned n = 0;
int priority;
char *label = NULL;
size_t label_len = 0;
assert(s);
assert(p);
@@ -1382,7 +1412,14 @@ static int stdout_stream_log(StdoutStream *s, const char *p) {
if (message)
IOVEC_SET_STRING(iovec[n++], message);
dispatch_message(s->server, iovec, n, ELEMENTSOF(iovec), &s->ucred, NULL, priority);
#ifdef HAVE_SELINUX
if (s->security_context) {
label = (char*) s->security_context;
label_len = strlen((char*) s->security_context);
}
#endif
dispatch_message(s->server, iovec, n, ELEMENTSOF(iovec), &s->ucred, NULL, label, label_len, priority);
free(message);
free(syslog_priority);
@@ -1576,6 +1613,11 @@ static void stdout_stream_free(StdoutStream *s) {
close_nointr_nofail(s->fd);
}
#ifdef HAVE_SELINUX
if (s->security_context)
freecon(s->security_context);
#endif
free(s->identifier);
free(s);
}
@@ -1619,6 +1661,11 @@ static int stdout_stream_new(Server *s) {
goto fail;
}
#ifdef HAVE_SELINUX
if (getpeercon(fd, &stream->security_context) < 0)
log_error("Failed to determine peer security context.");
#endif
if (shutdown(fd, SHUT_WR) < 0) {
log_error("Failed to shutdown writing side of socket: %m");
r = -errno;
@@ -1753,7 +1800,7 @@ static void proc_kmsg_line(Server *s, const char *p) {
if (message)
IOVEC_SET_STRING(iovec[n++], message);
dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, priority);
dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, NULL, 0, priority);
free(message);
free(syslog_priority);
@@ -2079,11 +2126,14 @@ static int process_event(Server *s, struct epoll_event *ev) {
struct ucred *ucred = NULL;
struct timeval *tv = NULL;
struct cmsghdr *cmsg;
char *label = NULL;
size_t label_len = 0;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(struct ucred)) +
CMSG_SPACE(sizeof(struct timeval)) +
CMSG_SPACE(sizeof(int))];
CMSG_SPACE(sizeof(int)) +
CMSG_SPACE(LINE_MAX)]; /* selinux label */
} control;
ssize_t n;
int v;
@@ -2139,6 +2189,10 @@ static int process_event(Server *s, struct epoll_event *ev) {
cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)))
ucred = (struct ucred*) CMSG_DATA(cmsg);
else if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_SECURITY) {
label = (char*) CMSG_DATA(cmsg);
label_len = cmsg->cmsg_len - CMSG_LEN(0);
} else if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SO_TIMESTAMP &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct timeval)))
tv = (struct timeval*) CMSG_DATA(cmsg);
@@ -2159,15 +2213,15 @@ static int process_event(Server *s, struct epoll_event *ev) {
else
s->buffer[n] = 0;
process_syslog_message(s, strstrip(s->buffer), ucred, tv);
process_syslog_message(s, strstrip(s->buffer), ucred, tv, label, label_len);
} else if (n_fds > 0)
log_warning("Got file descriptors via syslog socket. Ignoring.");
} else {
if (n > 0 && n_fds == 0)
process_native_message(s, s->buffer, n, ucred, tv);
process_native_message(s, s->buffer, n, ucred, tv, label, label_len);
else if (n == 0 && n_fds == 1)
process_native_file(s, fds[0], ucred, tv);
process_native_file(s, fds[0], ucred, tv, label, label_len);
else if (n_fds > 0)
log_warning("Got too many file descriptors via native socket. Ignoring.");
}