chiark / gitweb /
journald: fix off by one in native transport
[elogind.git] / src / journal / journald-native.c
index 9d1f39f0c5e855ab999018d95781db4f07381686..e994752558e4f9a70886da6721b101ef8a797179 100644 (file)
 #include <unistd.h>
 #include <stddef.h>
 #include <sys/epoll.h>
+#include <sys/mman.h>
 
 #include "socket-util.h"
 #include "path-util.h"
+#include "selinux-util.h"
 #include "journald-server.h"
 #include "journald-native.h"
 #include "journald-kmsg.h"
 #include "journald-console.h"
 #include "journald-syslog.h"
+#include "journald-wall.h"
+#include "memfd-util.h"
 
-/* Make sure not to make this smaller than the maximum coredump
- * size. See COREDUMP_MAX in coredump.c */
-#define ENTRY_SIZE_MAX (1024*1024*768)
-#define DATA_SIZE_MAX (1024*1024*768)
-
-static bool valid_user_field(const char *p, size_t l) {
+bool valid_user_field(const char *p, size_t l, bool allow_protected) {
         const char *a;
 
         /* We kinda enforce POSIX syntax recommendations for
@@ -54,7 +53,7 @@ static bool valid_user_field(const char *p, size_t l) {
                 return false;
 
         /* Variables starting with an underscore are protected */
-        if (p[0] == '_')
+        if (!allow_protected && p[0] == '_')
                 return false;
 
         /* Don't allow digits as first character */
@@ -63,27 +62,32 @@ static bool valid_user_field(const char *p, size_t l) {
 
         /* Only allow A-Z0-9 and '_' */
         for (a = p; a < p + l; a++)
-                if (!((*a >= 'A' && *a <= 'Z') ||
-                      (*a >= '0' && *a <= '9') ||
-                      *a == '_'))
+                if ((*a < 'A' || *a > 'Z') &&
+                    (*a < '0' || *a > '9') &&
+                    *a != '_')
                         return false;
 
         return true;
 }
 
+static bool allow_object_pid(const struct ucred *ucred) {
+        return ucred && ucred->uid == 0;
+}
+
 void server_process_native_message(
                 Server *s,
                 const void *buffer, size_t buffer_size,
-                struct ucred *ucred,
-                struct timeval *tv,
+                const struct ucred *ucred,
+                const struct timeval *tv,
                 const char *label, size_t label_len) {
 
         struct iovec *iovec = NULL;
-        unsigned n = 0, m = 0, j, tn = (unsigned) -1;
+        unsigned n = 0, j, tn = (unsigned) -1;
         const char *p;
-        size_t remaining;
+        size_t remaining, m = 0, entry_size = 0;
         int priority = LOG_INFO;
         char *identifier = NULL, *message = NULL;
+        pid_t object_pid = 0;
 
         assert(s);
         assert(buffer || buffer_size == 0);
@@ -104,9 +108,16 @@ void server_process_native_message(
 
                 if (e == p) {
                         /* Entry separator */
-                        server_dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, NULL, priority);
+
+                        if (entry_size + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
+                                log_debug("Entry is too big with %u properties and %zu bytes, ignoring.", n, entry_size);
+                                continue;
+                        }
+
+                        server_dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, NULL, priority, object_pid);
                         n = 0;
                         priority = LOG_INFO;
+                        entry_size = 0;
 
                         p++;
                         remaining--;
@@ -123,24 +134,15 @@ void server_process_native_message(
 
                 /* A property follows */
 
-                if (n+N_IOVEC_META_FIELDS >= m) {
-                        struct iovec *c;
-                        unsigned u;
-
-                        u = MAX((n+N_IOVEC_META_FIELDS+1) * 2U, 4U);
-                        c = realloc(iovec, u * sizeof(struct iovec));
-                        if (!c) {
-                                log_oom();
-                                break;
-                        }
-
-                        iovec = c;
-                        m = u;
+                /* n existing properties, 1 new, +1 for _TRANSPORT */
+                if (!GREEDY_REALLOC(iovec, m, n + 2 + N_IOVEC_META_FIELDS + !!object_pid * N_IOVEC_OBJECT_FIELDS)) {
+                        log_oom();
+                        break;
                 }
 
                 q = memchr(p, '=', e - p);
                 if (q) {
-                        if (valid_user_field(p, q - p)) {
+                        if (valid_user_field(p, q - p, false)) {
                                 size_t l;
 
                                 l = e - p;
@@ -151,29 +153,30 @@ void server_process_native_message(
                                  * field */
                                 iovec[n].iov_base = (char*) p;
                                 iovec[n].iov_len = l;
+                                entry_size += iovec[n].iov_len;
                                 n++;
 
                                 /* We need to determine the priority
                                  * of this entry for the rate limiting
                                  * logic */
                                 if (l == 10 &&
-                                    memcmp(p, "PRIORITY=", 9) == 0 &&
+                                    startswith(p, "PRIORITY=") &&
                                     p[9] >= '0' && p[9] <= '9')
                                         priority = (priority & LOG_FACMASK) | (p[9] - '0');
 
                                 else if (l == 17 &&
-                                         memcmp(p, "SYSLOG_FACILITY=", 16) == 0 &&
+                                         startswith(p, "SYSLOG_FACILITY=") &&
                                          p[16] >= '0' && p[16] <= '9')
                                         priority = (priority & LOG_PRIMASK) | ((p[16] - '0') << 3);
 
                                 else if (l == 18 &&
-                                         memcmp(p, "SYSLOG_FACILITY=", 16) == 0 &&
+                                         startswith(p, "SYSLOG_FACILITY=") &&
                                          p[16] >= '0' && p[16] <= '9' &&
                                          p[17] >= '0' && p[17] <= '9')
                                         priority = (priority & LOG_PRIMASK) | (((p[16] - '0')*10 + (p[17] - '0')) << 3);
 
                                 else if (l >= 19 &&
-                                         memcmp(p, "SYSLOG_IDENTIFIER=", 18) == 0) {
+                                         startswith(p, "SYSLOG_IDENTIFIER=")) {
                                         char *t;
 
                                         t = strndup(p + 18, l - 18);
@@ -182,7 +185,7 @@ void server_process_native_message(
                                                 identifier = t;
                                         }
                                 } else if (l >= 8 &&
-                                           memcmp(p, "MESSAGE=", 8) == 0) {
+                                           startswith(p, "MESSAGE=")) {
                                         char *t;
 
                                         t = strndup(p + 8, l - 8);
@@ -190,6 +193,16 @@ void server_process_native_message(
                                                 free(message);
                                                 message = t;
                                         }
+                                } else if (l > strlen("OBJECT_PID=") &&
+                                           l < strlen("OBJECT_PID=")  + DECIMAL_STR_MAX(pid_t) &&
+                                           startswith(p, "OBJECT_PID=") &&
+                                           allow_object_pid(ucred)) {
+                                        char buf[DECIMAL_STR_MAX(pid_t)];
+                                        memcpy(buf, p + strlen("OBJECT_PID="), l - strlen("OBJECT_PID="));
+                                        char_array_0(buf);
+
+                                        /* ignore error */
+                                        parse_pid(buf, &object_pid);
                                 }
                         }
 
@@ -210,7 +223,7 @@ void server_process_native_message(
                         l = le64toh(l_le);
 
                         if (l > DATA_SIZE_MAX) {
-                                log_debug("Received binary data block too large, ignoring.");
+                                log_debug("Received binary data block of %"PRIu64" bytes is too large, ignoring.", l);
                                 break;
                         }
 
@@ -230,9 +243,10 @@ void server_process_native_message(
                         k[e - p] = '=';
                         memcpy(k + (e - p) + 1, e + 1 + sizeof(uint64_t), l);
 
-                        if (valid_user_field(p, e - p)) {
+                        if (valid_user_field(p, e - p, false)) {
                                 iovec[n].iov_base = k;
                                 iovec[n].iov_len = (e - p) + 1 + l;
+                                entry_size += iovec[n].iov_len;
                                 n++;
                         } else
                                 free(k);
@@ -247,6 +261,13 @@ void server_process_native_message(
 
         tn = n++;
         IOVEC_SET_STRING(iovec[tn], "_TRANSPORT=journal");
+        entry_size += strlen("_TRANSPORT=journal");
+
+        if (entry_size + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */
+                log_debug("Entry is too big with %u properties and %zu bytes, ignoring.",
+                          n, entry_size);
+                goto finish;
+        }
 
         if (message) {
                 if (s->forward_to_syslog)
@@ -257,9 +278,12 @@ void server_process_native_message(
 
                 if (s->forward_to_console)
                         server_forward_console(s, priority, identifier, message, ucred);
+
+                if (s->forward_to_wall)
+                        server_forward_wall(s, priority, identifier, message, ucred);
         }
 
-        server_dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, NULL, priority);
+        server_dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, NULL, priority, object_pid);
 
 finish:
         for (j = 0; j < n; j++)  {
@@ -279,22 +303,32 @@ finish:
 void server_process_native_file(
                 Server *s,
                 int fd,
-                struct ucred *ucred,
-                struct timeval *tv,
+                const struct ucred *ucred,
+                const struct timeval *tv,
                 const char *label, size_t label_len) {
 
         struct stat st;
-        _cleanup_free_ void *p = NULL;
-        ssize_t n;
+        bool sealed;
         int r;
 
+        /* Data is in the passed fd, since it didn't fit in a
+         * datagram. */
+
         assert(s);
         assert(fd >= 0);
 
-        if (!ucred || ucred->uid != 0) {
+        /* If it's a memfd, check if it is sealed. If so, we can just
+         * use map it and use it, and do not need to copy the data
+         * out. */
+        sealed = memfd_get_sealed(fd) > 0;
+
+        if (!sealed && (!ucred || ucred->uid != 0)) {
                 _cleanup_free_ char *sl = NULL, *k = NULL;
                 const char *e;
 
+                /* If this is not a sealed memfd, and the peer is unknown or
+                 * unprivileged, then verify the path. */
+
                 if (asprintf(&sl, "/proc/self/fd/%i", fd) < 0) {
                         log_oom();
                         return;
@@ -302,7 +336,7 @@ void server_process_native_file(
 
                 r = readlink_malloc(sl, &k);
                 if (r < 0) {
-                        log_error("readlink(%s) failed: %m", sl);
+                        log_error_errno(errno, "readlink(%s) failed: %m", sl);
                         return;
                 }
 
@@ -316,19 +350,14 @@ void server_process_native_file(
                         return;
                 }
 
-                if (!filename_is_safe(e)) {
+                if (!filename_is_valid(e)) {
                         log_error("Received file in subdirectory of allowed directories. Refusing.");
                         return;
                 }
         }
 
-        /* Data is in the passed file, since it didn't fit in a
-         * datagram. We can't map the file here, since clients might
-         * then truncate it and trigger a SIGBUS for us. So let's
-         * stupidly read it */
-
         if (fstat(fd, &st) < 0) {
-                log_error("Failed to stat passed file, ignoring: %m");
+                log_error_errno(errno, "Failed to stat passed file, ignoring: %m");
                 return;
         }
 
@@ -345,78 +374,88 @@ void server_process_native_file(
                 return;
         }
 
-        p = malloc(st.st_size);
-        if (!p) {
-                log_oom();
-                return;
-        }
+        if (sealed) {
+                void *p;
+                size_t ps;
+
+                /* The file is sealed, we can just map it and use it. */
 
-        n = pread(fd, p, st.st_size, 0);
-        if (n < 0)
-                log_error("Failed to read file, ignoring: %s", strerror(-n));
-        else if (n > 0)
-                server_process_native_message(s, p, n, ucred, tv, label, label_len);
+                ps = PAGE_ALIGN(st.st_size);
+                p = mmap(NULL, ps, PROT_READ, MAP_PRIVATE, fd, 0);
+                if (p == MAP_FAILED) {
+                        log_error_errno(errno, "Failed to map memfd, ignoring: %m");
+                        return;
+                }
+
+                server_process_native_message(s, p, st.st_size, ucred, tv, label, label_len);
+                assert_se(munmap(p, ps) >= 0);
+        } else {
+                _cleanup_free_ void *p = NULL;
+                ssize_t n;
+
+                /* The file is not sealed, we can't map the file here, since
+                 * clients might then truncate it and trigger a SIGBUS for
+                 * us. So let's stupidly read it */
+
+                p = malloc(st.st_size);
+                if (!p) {
+                        log_oom();
+                        return;
+                }
+
+                n = pread(fd, p, st.st_size, 0);
+                if (n < 0)
+                        log_error_errno(n, "Failed to read file, ignoring: %m");
+                else if (n > 0)
+                        server_process_native_message(s, p, n, ucred, tv, label, label_len);
+        }
 }
 
 int server_open_native_socket(Server*s) {
-        union sockaddr_union sa;
-        int one, r;
-        struct epoll_event ev;
+        static const int one = 1;
+        int r;
 
         assert(s);
 
         if (s->native_fd < 0) {
+                union sockaddr_union sa = {
+                        .un.sun_family = AF_UNIX,
+                        .un.sun_path = "/run/systemd/journal/socket",
+                };
 
                 s->native_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
-                if (s->native_fd < 0) {
-                        log_error("socket() failed: %m");
-                        return -errno;
-                }
-
-                zero(sa);
-                sa.un.sun_family = AF_UNIX;
-                strncpy(sa.un.sun_path, "/run/systemd/journal/socket", sizeof(sa.un.sun_path));
+                if (s->native_fd < 0)
+                        return log_error_errno(errno, "socket() failed: %m");
 
                 unlink(sa.un.sun_path);
 
                 r = bind(s->native_fd, &sa.sa, offsetof(union sockaddr_union, un.sun_path) + strlen(sa.un.sun_path));
-                if (r < 0) {
-                        log_error("bind() failed: %m");
-                        return -errno;
-                }
+                if (r < 0)
+                        return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);
 
                 chmod(sa.un.sun_path, 0666);
         } else
                 fd_nonblock(s->native_fd, 1);
 
-        one = 1;
         r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));
-        if (r < 0) {
-                log_error("SO_PASSCRED failed: %m");
-                return -errno;
-        }
+        if (r < 0)
+                return log_error_errno(errno, "SO_PASSCRED failed: %m");
 
 #ifdef HAVE_SELINUX
-        one = 1;
-        r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
-        if (r < 0)
-                log_warning("SO_PASSSEC failed: %m");
+        if (mac_selinux_use()) {
+                r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
+                if (r < 0)
+                        log_warning_errno(errno, "SO_PASSSEC failed: %m");
+        }
 #endif
 
-        one = 1;
         r = setsockopt(s->native_fd, SOL_SOCKET, SO_TIMESTAMP, &one, sizeof(one));
-        if (r < 0) {
-                log_error("SO_TIMESTAMP failed: %m");
-                return -errno;
-        }
+        if (r < 0)
+                return log_error_errno(errno, "SO_TIMESTAMP failed: %m");
 
-        zero(ev);
-        ev.events = EPOLLIN;
-        ev.data.fd = s->native_fd;
-        if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->native_fd, &ev) < 0) {
-                log_error("Failed to add native server fd to epoll object: %m");
-                return -errno;
-        }
+        r = sd_event_add_io(s->event, &s->native_event_source, s->native_fd, EPOLLIN, process_datagram, s);
+        if (r < 0)
+                return log_error_errno(r, "Failed to add native server fd to event loop: %m");
 
         return 0;
 }