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Diffstat (limited to 'src/libsystemd-bus/bus-socket.c')
-rw-r--r--src/libsystemd-bus/bus-socket.c393
1 files changed, 360 insertions, 33 deletions
diff --git a/src/libsystemd-bus/bus-socket.c b/src/libsystemd-bus/bus-socket.c
index de823d582f..cb1e942833 100644
--- a/src/libsystemd-bus/bus-socket.c
+++ b/src/libsystemd-bus/bus-socket.c
@@ -30,13 +30,14 @@
#include "macro.h"
#include "missing.h"
#include "strv.h"
+#include "utf8.h"
#include "sd-bus.h"
#include "bus-socket.h"
#include "bus-internal.h"
#include "bus-message.h"
-static void iovec_advance(struct iovec *iov, unsigned *idx, size_t size) {
+static void iovec_advance(struct iovec iov[], unsigned *idx, size_t size) {
while (size > 0) {
struct iovec *i = iov + *idx;
@@ -56,6 +57,23 @@ static void iovec_advance(struct iovec *iov, unsigned *idx, size_t size) {
}
}
+bool bus_socket_auth_needs_write(sd_bus *b) {
+
+ unsigned i;
+
+ if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
+ return false;
+
+ for (i = b->auth_index; i < ELEMENTSOF(b->auth_iovec); i++) {
+ struct iovec *j = b->auth_iovec + i;
+
+ if (j->iov_len > 0)
+ return true;
+ }
+
+ return false;
+}
+
static int bus_socket_write_auth(sd_bus *b) {
struct msghdr mh;
ssize_t k;
@@ -63,12 +81,9 @@ static int bus_socket_write_auth(sd_bus *b) {
assert(b);
assert(b->state == BUS_AUTHENTICATING);
- if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
+ if (!bus_socket_auth_needs_write(b))
return 0;
- if (b->auth_timeout == 0)
- b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_DEFAULT_TIMEOUT;
-
zero(mh);
mh.msg_iov = b->auth_iovec + b->auth_index;
mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
@@ -82,12 +97,14 @@ static int bus_socket_write_auth(sd_bus *b) {
return 1;
}
-static int bus_socket_auth_verify(sd_bus *b) {
+static int bus_socket_auth_verify_client(sd_bus *b) {
char *e, *f, *start;
sd_id128_t peer;
unsigned i;
int r;
+ assert(b);
+
/* We expect two response lines: "OK" and possibly
* "AGREE_UNIX_FD" */
@@ -115,6 +132,8 @@ static int bus_socket_auth_verify(sd_bus *b) {
if (memcmp(b->rbuffer, "OK ", 3))
return -EPERM;
+ b->auth = b->anonymous_auth ? BUS_AUTH_ANONYMOUS : BUS_AUTH_EXTERNAL;
+
for (i = 0; i < 32; i += 2) {
int x, y;
@@ -150,6 +169,254 @@ static int bus_socket_auth_verify(sd_bus *b) {
return 1;
}
+static bool line_equals(const char *s, size_t m, const char *line) {
+ size_t l;
+
+ l = strlen(line);
+ if (l != m)
+ return false;
+
+ return memcmp(s, line, l) == 0;
+}
+
+static bool line_begins(const char *s, size_t m, const char *word) {
+ size_t l;
+
+ l = strlen(word);
+ if (m < l)
+ return false;
+
+ if (memcmp(s, word, l) != 0)
+ return false;
+
+ return m == l || (m > l && s[l] == ' ');
+}
+
+static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
+ _cleanup_free_ char *token = NULL;
+
+ if (!b->anonymous_auth)
+ return 0;
+
+ if (l <= 0)
+ return 1;
+
+ assert(p[0] == ' ');
+ p++; l--;
+
+ if (l % 2 != 0)
+ return 0;
+ token = unhexmem(p, l);
+ if (!token)
+ return -ENOMEM;
+
+ if (memchr(token, 0, l/2))
+ return 0;
+
+ return !!utf8_is_valid(token);
+}
+
+static int verify_external_token(sd_bus *b, const char *p, size_t l) {
+ _cleanup_free_ char *token = NULL;
+ uid_t u;
+ int r;
+
+ /* We don't do any real authentication here. Instead, we if
+ * the owner of this bus wanted authentication he should have
+ * checked SO_PEERCRED before even creating the bus object. */
+
+ if (!b->ucred_valid)
+ return 0;
+
+ if (l <= 0)
+ return 1;
+
+ assert(p[0] == ' ');
+ p++; l--;
+
+ if (l % 2 != 0)
+ return 0;
+
+ token = unhexmem(p, l);
+ if (!token)
+ return -ENOMEM;
+
+ if (memchr(token, 0, l/2))
+ return 0;
+
+ r = parse_uid(token, &u);
+ if (r < 0)
+ return 0;
+
+ if (u != b->ucred.uid)
+ return 0;
+
+ return 1;
+}
+
+static int bus_socket_auth_write(sd_bus *b, const char *t) {
+ char *p;
+ size_t l;
+
+ assert(b);
+ assert(t);
+
+ /* We only make use of the first iovec */
+ assert(b->auth_index == 0 || b->auth_index == 1);
+
+ l = strlen(t);
+ p = malloc(b->auth_iovec[0].iov_len + l);
+ if (!p)
+ return -ENOMEM;
+
+ memcpy(p, b->auth_iovec[0].iov_base, b->auth_iovec[0].iov_len);
+ memcpy(p + b->auth_iovec[0].iov_len, t, l);
+
+ b->auth_iovec[0].iov_base = p;
+ b->auth_iovec[0].iov_len += l;
+
+ free(b->auth_buffer);
+ b->auth_buffer = p;
+ b->auth_index = 0;
+ return 0;
+}
+
+static int bus_socket_auth_write_ok(sd_bus *b) {
+ char t[3 + 32 + 2 + 1];
+
+ assert(b);
+
+ snprintf(t, sizeof(t), "OK " SD_ID128_FORMAT_STR "\r\n", SD_ID128_FORMAT_VAL(b->peer));
+ char_array_0(t);
+
+ return bus_socket_auth_write(b, t);
+}
+
+static int bus_socket_auth_verify_server(sd_bus *b) {
+ char *e;
+ const char *line;
+ size_t l;
+ bool processed = false;
+ int r;
+
+ assert(b);
+
+ if (b->rbuffer_size < 3)
+ return 0;
+
+ /* First char must be a NUL byte */
+ if (*(char*) b->rbuffer != 0)
+ return -EIO;
+
+ /* Begin with the first line */
+ if (b->auth_rbegin <= 0)
+ b->auth_rbegin = 1;
+
+ for (;;) {
+ /* Check if line is complete */
+ line = (char*) b->rbuffer + b->auth_rbegin;
+ e = memmem(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2);
+ if (!e)
+ return processed;
+
+ l = e - line;
+
+ if (line_begins(line, l, "AUTH ANONYMOUS")) {
+
+ r = verify_anonymous_token(b, line + 14, l - 14);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ r = bus_socket_auth_write(b, "REJECTED\r\n");
+ else {
+ b->auth = BUS_AUTH_ANONYMOUS;
+ r = bus_socket_auth_write_ok(b);
+ }
+
+ } else if (line_begins(line, l, "AUTH EXTERNAL")) {
+
+ r = verify_external_token(b, line + 13, l - 13);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ r = bus_socket_auth_write(b, "REJECTED\r\n");
+ else {
+ b->auth = BUS_AUTH_EXTERNAL;
+ r = bus_socket_auth_write_ok(b);
+ }
+
+ } else if (line_begins(line, l, "AUTH"))
+ r = bus_socket_auth_write(b, "REJECTED EXTERNAL ANONYMOUS\r\n");
+ else if (line_equals(line, l, "CANCEL") ||
+ line_begins(line, l, "ERROR")) {
+
+ b->auth = _BUS_AUTH_INVALID;
+ r = bus_socket_auth_write(b, "REJECTED\r\n");
+
+ } else if (line_equals(line, l, "BEGIN")) {
+
+ if (b->auth == _BUS_AUTH_INVALID)
+ r = bus_socket_auth_write(b, "ERROR\r\n");
+ else {
+ /* We can't leave from the auth phase
+ * before we haven't written
+ * everything queued, so let's check
+ * that */
+
+ if (bus_socket_auth_needs_write(b))
+ return 1;
+
+ b->rbuffer_size -= (e + 2 - (char*) b->rbuffer);
+ memmove(b->rbuffer, e + 2, b->rbuffer_size);
+ return bus_start_running(b);
+ }
+
+ } else if (line_begins(line, l, "DATA")) {
+
+ if (b->auth == _BUS_AUTH_INVALID)
+ r = bus_socket_auth_write(b, "ERROR\r\n");
+ else {
+ if (b->auth == BUS_AUTH_ANONYMOUS)
+ r = verify_anonymous_token(b, line + 4, l - 4);
+ else
+ r = verify_external_token(b, line + 4, l - 4);
+
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ b->auth = _BUS_AUTH_INVALID;
+ r = bus_socket_auth_write(b, "REJECTED\r\n");
+ } else
+ r = bus_socket_auth_write_ok(b);
+ }
+ } else if (line_equals(line, l, "NEGOTIATE_UNIX_FD")) {
+ if (b->auth == _BUS_AUTH_INVALID || !b->negotiate_fds)
+ r = bus_socket_auth_write(b, "ERROR\r\n");
+ else {
+ b->can_fds = true;
+ r = bus_socket_auth_write(b, "AGREE_UNIX_FD\r\n");
+ }
+ } else
+ r = bus_socket_auth_write(b, "ERROR\r\n");
+
+ if (r < 0)
+ return r;
+
+ b->auth_rbegin = e + 2 - (char*) b->rbuffer;
+
+ processed = true;
+ }
+}
+
+static int bus_socket_auth_verify(sd_bus *b) {
+ assert(b);
+
+ if (b->is_server)
+ return bus_socket_auth_verify_server(b);
+ else
+ return bus_socket_auth_verify_client(b);
+}
+
static int bus_socket_read_auth(sd_bus *b) {
struct msghdr mh;
struct iovec iov;
@@ -157,14 +424,22 @@ static int bus_socket_read_auth(sd_bus *b) {
ssize_t k;
int r;
void *p;
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
+ CMSG_SPACE(sizeof(struct ucred)) +
+ CMSG_SPACE(NAME_MAX)]; /*selinux label */
+ } control;
+ struct cmsghdr *cmsg;
assert(b);
+ assert(b->state == BUS_AUTHENTICATING);
r = bus_socket_auth_verify(b);
if (r != 0)
return r;
- n = MAX(3 + 32 + 2 + sizeof("AGREE_UNIX_FD") - 1 + 2, b->rbuffer_size * 2);
+ n = MAX(256, b->rbuffer_size * 2);
if (n > BUS_AUTH_SIZE_MAX)
n = BUS_AUTH_SIZE_MAX;
@@ -185,8 +460,10 @@ static int bus_socket_read_auth(sd_bus *b) {
zero(mh);
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
+ mh.msg_control = &control;
+ mh.msg_controllen = sizeof(control);
- k = recvmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+ k = recvmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
if (k < 0)
return errno == EAGAIN ? 0 : -errno;
if (k == 0)
@@ -194,6 +471,35 @@ static int bus_socket_read_auth(sd_bus *b) {
b->rbuffer_size += k;
+ for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+ if (cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_RIGHTS) {
+ int j;
+
+ /* Whut? We received fds during the auth
+ * protocol? Somebody is playing games with
+ * us. Close them all, and fail */
+ j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+ close_many((int*) CMSG_DATA(cmsg), j);
+ return -EIO;
+
+ } else if (cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_CREDENTIALS &&
+ cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
+
+ memcpy(&b->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
+ b->ucred_valid = true;
+
+ } else if (cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_SECURITY) {
+
+ size_t l;
+ l = cmsg->cmsg_len - CMSG_LEN(0);
+ memcpy(&b->label, CMSG_DATA(cmsg), l);
+ b->label[l] = 0;
+ }
+ }
+
r = bus_socket_auth_verify(b);
if (r != 0)
return r;
@@ -219,50 +525,71 @@ static int bus_socket_setup(sd_bus *b) {
return 0;
}
-static int bus_socket_start_auth(sd_bus *b) {
- static const char auth_prefix[] = "\0AUTH EXTERNAL ";
- static const char auth_suffix_with_unix_fd[] = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
- static const char auth_suffix_without_unix_fd[] = "\r\nBEGIN\r\n";
-
- char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
+static int bus_socket_start_auth_client(sd_bus *b) {
size_t l;
- const char *auth_suffix;
- int domain = 0, r;
- socklen_t sl;
+ const char *auth_suffix, *auth_prefix;
assert(b);
- b->state = BUS_AUTHENTICATING;
+ if (b->anonymous_auth) {
+ auth_prefix = "\0AUTH ANONYMOUS ";
- sl = sizeof(domain);
- r = getsockopt(b->fd, SOL_SOCKET, SO_DOMAIN, &domain, &sl);
- if (r < 0)
- return -errno;
+ /* For ANONYMOUS auth we send some arbitrary "trace" string */
+ l = 9;
+ b->auth_buffer = hexmem("anonymous", l);
+ } else {
+ char text[20 + 1]; /* enough space for a 64bit integer plus NUL */
- if (domain != AF_UNIX)
- b->negotiate_fds = false;
+ auth_prefix = "\0AUTH EXTERNAL ";
- snprintf(text, sizeof(text), "%llu", (unsigned long long) geteuid());
- char_array_0(text);
+ snprintf(text, sizeof(text), "%lu", (unsigned long) geteuid());
+ char_array_0(text);
- l = strlen(text);
- b->auth_uid = hexmem(text, l);
- if (!b->auth_uid)
+ l = strlen(text);
+ b->auth_buffer = hexmem(text, l);
+ }
+
+ if (!b->auth_buffer)
return -ENOMEM;
- auth_suffix = b->negotiate_fds ? auth_suffix_with_unix_fd : auth_suffix_without_unix_fd;
+ if (b->negotiate_fds)
+ auth_suffix = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
+ else
+ auth_suffix = "\r\nBEGIN\r\n";
b->auth_iovec[0].iov_base = (void*) auth_prefix;
- b->auth_iovec[0].iov_len = sizeof(auth_prefix) -1;
- b->auth_iovec[1].iov_base = (void*) b->auth_uid;
+ b->auth_iovec[0].iov_len = 1 + strlen(auth_prefix + 1);
+ b->auth_iovec[1].iov_base = (void*) b->auth_buffer;
b->auth_iovec[1].iov_len = l * 2;
b->auth_iovec[2].iov_base = (void*) auth_suffix;
b->auth_iovec[2].iov_len = strlen(auth_suffix);
- b->auth_size = sizeof(auth_prefix) - 1 + l * 2 + sizeof(auth_suffix) - 1;
return bus_socket_write_auth(b);
}
+static int bus_socket_start_auth(sd_bus *b) {
+ int domain = 0, r;
+ socklen_t sl;
+
+ assert(b);
+
+ b->state = BUS_AUTHENTICATING;
+ b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_DEFAULT_TIMEOUT;
+
+ sl = sizeof(domain);
+ r = getsockopt(b->fd, SOL_SOCKET, SO_DOMAIN, &domain, &sl);
+ if (r < 0)
+ return -errno;
+
+ if (domain != AF_UNIX)
+ b->negotiate_fds = false;
+
+ if (b->is_server)
+ return bus_socket_read_auth(b);
+ else
+ return bus_socket_start_auth_client(b);
+}
+
int bus_socket_connect(sd_bus *b) {
int r;
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-10 15:19:12 +0000