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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:35:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:35:18 +0000 |
commit | b750101eb236130cf056c675997decbac904cc49 (patch) | |
tree | a5df1a06754bdd014cb975c051c83b01c9a97532 /src/journal/journald-native.c | |
parent | Initial commit. (diff) | |
download | systemd-b750101eb236130cf056c675997decbac904cc49.tar.xz systemd-b750101eb236130cf056c675997decbac904cc49.zip |
Adding upstream version 252.22.upstream/252.22upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/journal/journald-native.c | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/src/journal/journald-native.c b/src/journal/journald-native.c new file mode 100644 index 0000000..0325788 --- /dev/null +++ b/src/journal/journald-native.c @@ -0,0 +1,505 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <stddef.h> +#include <sys/epoll.h> +#include <sys/mman.h> +#include <sys/statvfs.h> +#include <unistd.h> + +#include "alloc-util.h" +#include "fd-util.h" +#include "fs-util.h" +#include "io-util.h" +#include "journal-importer.h" +#include "journal-util.h" +#include "journald-console.h" +#include "journald-kmsg.h" +#include "journald-native.h" +#include "journald-server.h" +#include "journald-syslog.h" +#include "journald-wall.h" +#include "memfd-util.h" +#include "memory-util.h" +#include "parse-util.h" +#include "path-util.h" +#include "process-util.h" +#include "selinux-util.h" +#include "socket-util.h" +#include "string-util.h" +#include "strv.h" +#include "unaligned.h" + +static bool allow_object_pid(const struct ucred *ucred) { + return ucred && ucred->uid == 0; +} + +static void server_process_entry_meta( + const char *p, size_t l, + const struct ucred *ucred, + int *priority, + char **identifier, + char **message, + pid_t *object_pid) { + + /* We need to determine the priority of this entry for the rate limiting logic */ + + if (l == 10 && + startswith(p, "PRIORITY=") && + p[9] >= '0' && p[9] <= '9') + *priority = (*priority & LOG_FACMASK) | (p[9] - '0'); + + else if (l == 17 && + startswith(p, "SYSLOG_FACILITY=") && + p[16] >= '0' && p[16] <= '9') + *priority = (*priority & LOG_PRIMASK) | ((p[16] - '0') << 3); + + else if (l == 18 && + 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 && + startswith(p, "SYSLOG_IDENTIFIER=")) { + char *t; + + t = memdup_suffix0(p + 18, l - 18); + if (t) { + free(*identifier); + *identifier = t; + } + + } else if (l >= 8 && + startswith(p, "MESSAGE=")) { + char *t; + + t = memdup_suffix0(p + 8, l - 8); + if (t) { + 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=")); + buf[l-STRLEN("OBJECT_PID=")] = '\0'; + + (void) parse_pid(buf, object_pid); + } +} + +static int server_process_entry( + Server *s, + const void *buffer, size_t *remaining, + ClientContext *context, + const struct ucred *ucred, + const struct timeval *tv, + const char *label, size_t label_len) { + + /* Process a single entry from a native message. Returns 0 if nothing special happened and the message + * processing should continue, and a negative or positive value otherwise. + * + * Note that *remaining is altered on both success and failure. */ + + size_t n = 0, j, tn = SIZE_MAX, entry_size = 0; + char *identifier = NULL, *message = NULL; + struct iovec *iovec = NULL; + int priority = LOG_INFO; + pid_t object_pid = 0; + const char *p; + int r = 1; + + p = buffer; + + while (*remaining > 0) { + const char *e, *q; + + e = memchr(p, '\n', *remaining); + + if (!e) { + /* Trailing noise, let's ignore it, and flush what we collected */ + log_debug("Received message with trailing noise, ignoring."); + break; /* finish processing of the message */ + } + + if (e == p) { + /* Entry separator */ + *remaining -= 1; + break; + } + + if (IN_SET(*p, '.', '#')) { + /* Ignore control commands for now, and comments too. */ + *remaining -= (e - p) + 1; + p = e + 1; + continue; + } + + /* A property follows */ + if (n > ENTRY_FIELD_COUNT_MAX) { + log_debug("Received an entry that has more than " STRINGIFY(ENTRY_FIELD_COUNT_MAX) " fields, ignoring entry."); + goto finish; + } + + /* n existing properties, 1 new, +1 for _TRANSPORT */ + if (!GREEDY_REALLOC(iovec, + n + 2 + + N_IOVEC_META_FIELDS + N_IOVEC_OBJECT_FIELDS + + client_context_extra_fields_n_iovec(context))) { + r = log_oom(); + goto finish; + } + + q = memchr(p, '=', e - p); + if (q) { + if (journal_field_valid(p, q - p, false)) { + size_t l; + + l = e - p; + if (l > DATA_SIZE_MAX) { + log_debug("Received text block of %zu bytes is too large, ignoring entry.", l); + goto finish; + } + + if (entry_size + l + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */ + log_debug("Entry is too big (%zu bytes after processing %zu entries), ignoring entry.", + entry_size + l, n + 1); + goto finish; + } + + /* If the field name starts with an underscore, skip the variable, since that indicates + * a trusted field */ + iovec[n++] = IOVEC_MAKE((char*) p, l); + entry_size += l; + + server_process_entry_meta(p, l, ucred, + &priority, + &identifier, + &message, + &object_pid); + } + + *remaining -= (e - p) + 1; + p = e + 1; + continue; + } else { + uint64_t l, total; + char *k; + + if (*remaining < e - p + 1 + sizeof(uint64_t) + 1) { + log_debug("Failed to parse message, ignoring."); + break; + } + + l = unaligned_read_le64(e + 1); + if (l > DATA_SIZE_MAX) { + log_debug("Received binary data block of %"PRIu64" bytes is too large, ignoring entry.", l); + goto finish; + } + + total = (e - p) + 1 + l; + if (entry_size + total + n + 1 > ENTRY_SIZE_MAX) { /* data + separators + trailer */ + log_debug("Entry is too big (%"PRIu64"bytes after processing %zu fields), ignoring.", + entry_size + total, n + 1); + goto finish; + } + + if ((uint64_t) *remaining < e - p + 1 + sizeof(uint64_t) + l + 1 || + e[1+sizeof(uint64_t)+l] != '\n') { + log_debug("Failed to parse message, ignoring."); + break; + } + + k = malloc(total); + if (!k) { + log_oom(); + break; + } + + memcpy(k, p, e - p); + k[e - p] = '='; + memcpy(k + (e - p) + 1, e + 1 + sizeof(uint64_t), l); + + if (journal_field_valid(p, e - p, false)) { + iovec[n] = IOVEC_MAKE(k, (e - p) + 1 + l); + entry_size += iovec[n].iov_len; + n++; + + server_process_entry_meta(k, (e - p) + 1 + l, ucred, + &priority, + &identifier, + &message, + &object_pid); + } else + free(k); + + *remaining -= (e - p) + 1 + sizeof(uint64_t) + l + 1; + p = e + 1 + sizeof(uint64_t) + l + 1; + } + } + + if (n <= 0) + goto finish; + + tn = n++; + iovec[tn] = IOVEC_MAKE_STRING("_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 %zu properties and %zu bytes, ignoring.", n, entry_size); + goto finish; + } + + r = 0; /* Success, we read the message. */ + + if (!client_context_test_priority(context, priority)) + goto finish; + + if (message) { + if (s->forward_to_syslog) + server_forward_syslog(s, syslog_fixup_facility(priority), identifier, message, ucred, tv); + + if (s->forward_to_kmsg) + server_forward_kmsg(s, priority, identifier, message, ucred); + + 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, MALLOC_ELEMENTSOF(iovec), context, tv, priority, object_pid); + +finish: + for (j = 0; j < n; j++) { + if (j == tn) + continue; + + if (iovec[j].iov_base < buffer || + (const char*) iovec[j].iov_base >= p + *remaining) + free(iovec[j].iov_base); + } + + free(iovec); + free(identifier); + free(message); + + return r; +} + +void server_process_native_message( + Server *s, + const char *buffer, size_t buffer_size, + const struct ucred *ucred, + const struct timeval *tv, + const char *label, size_t label_len) { + + size_t remaining = buffer_size; + ClientContext *context = NULL; + int r; + + assert(s); + assert(buffer || buffer_size == 0); + + if (ucred && pid_is_valid(ucred->pid)) { + r = client_context_get(s, ucred->pid, ucred, label, label_len, NULL, &context); + if (r < 0) + log_warning_errno(r, "Failed to retrieve credentials for PID " PID_FMT ", ignoring: %m", ucred->pid); + } + + do { + r = server_process_entry(s, + (const uint8_t*) buffer + (buffer_size - remaining), &remaining, + context, ucred, tv, label, label_len); + } while (r == 0); +} + +void server_process_native_file( + Server *s, + int fd, + const struct ucred *ucred, + const struct timeval *tv, + const char *label, size_t label_len) { + + struct stat st; + bool sealed; + int r; + + /* Data is in the passed fd, probably it didn't fit in a datagram. */ + + assert(s); + assert(fd >= 0); + + /* If it's a memfd, check if it is sealed. If so, we can just + * mmap 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 *k = NULL; + const char *e; + + /* If this is not a sealed memfd, and the peer is unknown or + * unprivileged, then verify the path. */ + + r = fd_get_path(fd, &k); + if (r < 0) { + log_error_errno(r, "readlink(/proc/self/fd/%i) failed: %m", fd); + return; + } + + e = PATH_STARTSWITH_SET(k, "/dev/shm/", "/tmp/", "/var/tmp/"); + if (!e) { + log_error("Received file outside of allowed directories. Refusing."); + return; + } + + if (!filename_is_valid(e)) { + log_error("Received file in subdirectory of allowed directories. Refusing."); + return; + } + } + + if (fstat(fd, &st) < 0) { + log_error_errno(errno, "Failed to stat passed file, ignoring: %m"); + return; + } + + if (!S_ISREG(st.st_mode)) { + log_error("File passed is not regular. Ignoring."); + return; + } + + if (st.st_size <= 0) + return; + + /* When !sealed, set a lower memory limit. We have to read the file, + * effectively doubling memory use. */ + if (st.st_size > ENTRY_SIZE_MAX / (sealed ? 1 : 2)) { + log_error("File passed too large (%"PRIu64" bytes). Ignoring.", (uint64_t) st.st_size); + return; + } + + if (sealed) { + void *p; + size_t ps; + + /* The file is sealed, we can just map it and use it. */ + + 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; + struct statvfs vfs; + ssize_t n; + + if (fstatvfs(fd, &vfs) < 0) { + log_error_errno(errno, "Failed to stat file system of passed file, not processing it: %m"); + return; + } + + /* Refuse operating on file systems that have + * mandatory locking enabled, see: + * + * https://github.com/systemd/systemd/issues/1822 + */ + if (vfs.f_flag & ST_MANDLOCK) { + log_error("Received file descriptor from file system with mandatory locking enabled, not processing it."); + return; + } + + /* Make the fd non-blocking. On regular files this has + * the effect of bypassing mandatory locking. Of + * course, this should normally not be necessary given + * the check above, but let's better be safe than + * sorry, after all NFS is pretty confusing regarding + * file system flags, and we better don't trust it, + * and so is SMB. */ + r = fd_nonblock(fd, true); + if (r < 0) { + log_error_errno(r, "Failed to make fd non-blocking, not processing it: %m"); + return; + } + + /* 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(errno, "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, const char *native_socket) { + int r; + + assert(s); + assert(native_socket); + + if (s->native_fd < 0) { + union sockaddr_union sa; + size_t sa_len; + + r = sockaddr_un_set_path(&sa.un, native_socket); + if (r < 0) + return log_error_errno(r, "Unable to use namespace path %s for AF_UNIX socket: %m", native_socket); + sa_len = r; + + s->native_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (s->native_fd < 0) + return log_error_errno(errno, "socket() failed: %m"); + + (void) sockaddr_un_unlink(&sa.un); + + r = bind(s->native_fd, &sa.sa, sa_len); + if (r < 0) + return log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path); + + (void) chmod(sa.un.sun_path, 0666); + } else + (void) fd_nonblock(s->native_fd, true); + + r = setsockopt_int(s->native_fd, SOL_SOCKET, SO_PASSCRED, true); + if (r < 0) + return log_error_errno(r, "SO_PASSCRED failed: %m"); + + if (mac_selinux_use()) { + r = setsockopt_int(s->native_fd, SOL_SOCKET, SO_PASSSEC, true); + if (r < 0) + log_warning_errno(r, "SO_PASSSEC failed: %m"); + } + + r = setsockopt_int(s->native_fd, SOL_SOCKET, SO_TIMESTAMP, true); + if (r < 0) + return log_error_errno(r, "SO_TIMESTAMP failed: %m"); + + r = sd_event_add_io(s->event, &s->native_event_source, s->native_fd, EPOLLIN, server_process_datagram, s); + if (r < 0) + return log_error_errno(r, "Failed to add native server fd to event loop: %m"); + + r = sd_event_source_set_priority(s->native_event_source, SD_EVENT_PRIORITY_NORMAL+5); + if (r < 0) + return log_error_errno(r, "Failed to adjust native event source priority: %m"); + + return 0; +} |