journald: do not store the iovec entry for process commandline on stack
This fixes a crash where we would read the commandline, whose length is under control of the sending program, and then crash when trying to create a stack allocation for it. CVE-2018-16864 https://bugzilla.redhat.com/show_bug.cgi?id=1653855 The message actually doesn't get written to disk, because journal_file_append_entry() returns -E2BIG.
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bc2762a309
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084eeb865c
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@ -8,6 +8,7 @@
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#include <unistd.h>
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#include <unistd.h>
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#include "io-util.h"
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#include "io-util.h"
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#include "string-util.h"
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#include "time-util.h"
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#include "time-util.h"
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int flush_fd(int fd) {
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int flush_fd(int fd) {
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@ -252,3 +253,12 @@ ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length) {
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return q - (const uint8_t*) p;
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return q - (const uint8_t*) p;
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}
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}
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char* set_iovec_string_field(struct iovec *iovec, size_t *n_iovec, const char *field, const char *value) {
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char *x;
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x = strappend(field, value);
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if (x)
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iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(x);
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return x;
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}
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@ -71,3 +71,5 @@ static inline bool FILE_SIZE_VALID_OR_INFINITY(uint64_t l) {
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#define IOVEC_MAKE(base, len) (struct iovec) IOVEC_INIT(base, len)
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#define IOVEC_MAKE(base, len) (struct iovec) IOVEC_INIT(base, len)
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#define IOVEC_INIT_STRING(string) IOVEC_INIT((char*) string, strlen(string))
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#define IOVEC_INIT_STRING(string) IOVEC_INIT((char*) string, strlen(string))
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#define IOVEC_MAKE_STRING(string) (struct iovec) IOVEC_INIT_STRING(string)
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#define IOVEC_MAKE_STRING(string) (struct iovec) IOVEC_INIT_STRING(string)
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char* set_iovec_string_field(struct iovec *iovec, size_t *n_iovec, const char *field, const char *value);
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@ -1063,19 +1063,10 @@ static int send_iovec(const struct iovec iovec[], size_t n_iovec, int input_fd)
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return 0;
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return 0;
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}
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}
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static char* set_iovec_field(struct iovec *iovec, size_t *n_iovec, const char *field, const char *value) {
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char *x;
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x = strappend(field, value);
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if (x)
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iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(x);
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return x;
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}
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static char* set_iovec_field_free(struct iovec *iovec, size_t *n_iovec, const char *field, char *value) {
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static char* set_iovec_field_free(struct iovec *iovec, size_t *n_iovec, const char *field, char *value) {
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char *x;
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char *x;
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x = set_iovec_field(iovec, n_iovec, field, value);
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x = set_iovec_string_field(iovec, n_iovec, field, value);
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free(value);
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free(value);
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return x;
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return x;
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}
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}
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@ -1125,36 +1116,36 @@ static int gather_pid_metadata(
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disable_coredumps();
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disable_coredumps();
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}
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}
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set_iovec_field(iovec, n_iovec, "COREDUMP_UNIT=", context[CONTEXT_UNIT]);
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set_iovec_string_field(iovec, n_iovec, "COREDUMP_UNIT=", context[CONTEXT_UNIT]);
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}
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}
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if (cg_pid_get_user_unit(pid, &t) >= 0)
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if (cg_pid_get_user_unit(pid, &t) >= 0)
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set_iovec_field_free(iovec, n_iovec, "COREDUMP_USER_UNIT=", t);
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set_iovec_field_free(iovec, n_iovec, "COREDUMP_USER_UNIT=", t);
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/* The next few are mandatory */
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/* The next few are mandatory */
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if (!set_iovec_field(iovec, n_iovec, "COREDUMP_PID=", context[CONTEXT_PID]))
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if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_PID=", context[CONTEXT_PID]))
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return log_oom();
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return log_oom();
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if (!set_iovec_field(iovec, n_iovec, "COREDUMP_UID=", context[CONTEXT_UID]))
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if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_UID=", context[CONTEXT_UID]))
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return log_oom();
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return log_oom();
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if (!set_iovec_field(iovec, n_iovec, "COREDUMP_GID=", context[CONTEXT_GID]))
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if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_GID=", context[CONTEXT_GID]))
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return log_oom();
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return log_oom();
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if (!set_iovec_field(iovec, n_iovec, "COREDUMP_SIGNAL=", context[CONTEXT_SIGNAL]))
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if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_SIGNAL=", context[CONTEXT_SIGNAL]))
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return log_oom();
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return log_oom();
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if (!set_iovec_field(iovec, n_iovec, "COREDUMP_RLIMIT=", context[CONTEXT_RLIMIT]))
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if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_RLIMIT=", context[CONTEXT_RLIMIT]))
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return log_oom();
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return log_oom();
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if (!set_iovec_field(iovec, n_iovec, "COREDUMP_HOSTNAME=", context[CONTEXT_HOSTNAME]))
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if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_HOSTNAME=", context[CONTEXT_HOSTNAME]))
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return log_oom();
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return log_oom();
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if (!set_iovec_field(iovec, n_iovec, "COREDUMP_COMM=", context[CONTEXT_COMM]))
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if (!set_iovec_string_field(iovec, n_iovec, "COREDUMP_COMM=", context[CONTEXT_COMM]))
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return log_oom();
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return log_oom();
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if (context[CONTEXT_EXE] &&
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if (context[CONTEXT_EXE] &&
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!set_iovec_field(iovec, n_iovec, "COREDUMP_EXE=", context[CONTEXT_EXE]))
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!set_iovec_string_field(iovec, n_iovec, "COREDUMP_EXE=", context[CONTEXT_EXE]))
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return log_oom();
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return log_oom();
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if (sd_pid_get_session(pid, &t) >= 0)
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if (sd_pid_get_session(pid, &t) >= 0)
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@ -1222,7 +1213,7 @@ static int gather_pid_metadata(
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iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(t);
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iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(t);
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if (safe_atoi(context[CONTEXT_SIGNAL], &signo) >= 0 && SIGNAL_VALID(signo))
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if (safe_atoi(context[CONTEXT_SIGNAL], &signo) >= 0 && SIGNAL_VALID(signo))
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set_iovec_field(iovec, n_iovec, "COREDUMP_SIGNAL_NAME=SIG", signal_to_string(signo));
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set_iovec_string_field(iovec, n_iovec, "COREDUMP_SIGNAL_NAME=SIG", signal_to_string(signo));
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return 0; /* we successfully acquired all metadata */
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return 0; /* we successfully acquired all metadata */
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}
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}
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@ -905,6 +905,7 @@ static void dispatch_message_real(
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pid_t object_pid) {
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pid_t object_pid) {
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char source_time[sizeof("_SOURCE_REALTIME_TIMESTAMP=") + DECIMAL_STR_MAX(usec_t)];
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char source_time[sizeof("_SOURCE_REALTIME_TIMESTAMP=") + DECIMAL_STR_MAX(usec_t)];
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_cleanup_free_ char *cmdline1 = NULL, *cmdline2 = NULL;
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uid_t journal_uid;
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uid_t journal_uid;
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ClientContext *o;
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ClientContext *o;
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@ -921,20 +922,23 @@ static void dispatch_message_real(
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->uid, uid_t, uid_is_valid, UID_FMT, "_UID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->uid, uid_t, uid_is_valid, UID_FMT, "_UID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->gid, gid_t, gid_is_valid, GID_FMT, "_GID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->gid, gid_t, gid_is_valid, GID_FMT, "_GID");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->comm, "_COMM");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->comm, "_COMM"); /* At most TASK_COMM_LENGTH (16 bytes) */
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IOVEC_ADD_STRING_FIELD(iovec, n, c->exe, "_EXE");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->exe, "_EXE"); /* A path, so at most PATH_MAX (4096 bytes) */
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IOVEC_ADD_STRING_FIELD(iovec, n, c->cmdline, "_CMDLINE");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->capeff, "_CAP_EFFECTIVE");
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if (c->cmdline)
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/* At most _SC_ARG_MAX (2MB usually), which is too much to put on stack.
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* Let's use a heap allocation for this one. */
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cmdline1 = set_iovec_string_field(iovec, &n, "_CMDLINE=", c->cmdline);
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IOVEC_ADD_STRING_FIELD(iovec, n, c->capeff, "_CAP_EFFECTIVE"); /* Read from /proc/.../status */
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IOVEC_ADD_SIZED_FIELD(iovec, n, c->label, c->label_size, "_SELINUX_CONTEXT");
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IOVEC_ADD_SIZED_FIELD(iovec, n, c->label, c->label_size, "_SELINUX_CONTEXT");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->auditid, uint32_t, audit_session_is_valid, "%" PRIu32, "_AUDIT_SESSION");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->auditid, uint32_t, audit_session_is_valid, "%" PRIu32, "_AUDIT_SESSION");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->loginuid, uid_t, uid_is_valid, UID_FMT, "_AUDIT_LOGINUID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->loginuid, uid_t, uid_is_valid, UID_FMT, "_AUDIT_LOGINUID");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->cgroup, "_SYSTEMD_CGROUP");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->cgroup, "_SYSTEMD_CGROUP"); /* A path */
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IOVEC_ADD_STRING_FIELD(iovec, n, c->session, "_SYSTEMD_SESSION");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->session, "_SYSTEMD_SESSION");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->owner_uid, uid_t, uid_is_valid, UID_FMT, "_SYSTEMD_OWNER_UID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, c->owner_uid, uid_t, uid_is_valid, UID_FMT, "_SYSTEMD_OWNER_UID");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->unit, "_SYSTEMD_UNIT");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->unit, "_SYSTEMD_UNIT"); /* Unit names are bounded by UNIT_NAME_MAX */
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IOVEC_ADD_STRING_FIELD(iovec, n, c->user_unit, "_SYSTEMD_USER_UNIT");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->user_unit, "_SYSTEMD_USER_UNIT");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->slice, "_SYSTEMD_SLICE");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->slice, "_SYSTEMD_SLICE");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->user_slice, "_SYSTEMD_USER_SLICE");
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IOVEC_ADD_STRING_FIELD(iovec, n, c->user_slice, "_SYSTEMD_USER_SLICE");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, o->uid, uid_t, uid_is_valid, UID_FMT, "OBJECT_UID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, o->uid, uid_t, uid_is_valid, UID_FMT, "OBJECT_UID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, o->gid, gid_t, gid_is_valid, GID_FMT, "OBJECT_GID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, o->gid, gid_t, gid_is_valid, GID_FMT, "OBJECT_GID");
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/* See above for size limits, only ->cmdline may be large, so use a heap allocation for it. */
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IOVEC_ADD_STRING_FIELD(iovec, n, o->comm, "OBJECT_COMM");
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IOVEC_ADD_STRING_FIELD(iovec, n, o->comm, "OBJECT_COMM");
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IOVEC_ADD_STRING_FIELD(iovec, n, o->exe, "OBJECT_EXE");
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IOVEC_ADD_STRING_FIELD(iovec, n, o->exe, "OBJECT_EXE");
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IOVEC_ADD_STRING_FIELD(iovec, n, o->cmdline, "OBJECT_CMDLINE");
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if (o->cmdline)
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cmdline2 = set_iovec_string_field(iovec, &n, "OBJECT_CMDLINE=", o->cmdline);
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IOVEC_ADD_STRING_FIELD(iovec, n, o->capeff, "OBJECT_CAP_EFFECTIVE");
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IOVEC_ADD_STRING_FIELD(iovec, n, o->capeff, "OBJECT_CAP_EFFECTIVE");
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IOVEC_ADD_SIZED_FIELD(iovec, n, o->label, o->label_size, "OBJECT_SELINUX_CONTEXT");
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IOVEC_ADD_SIZED_FIELD(iovec, n, o->label, o->label_size, "OBJECT_SELINUX_CONTEXT");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, o->auditid, uint32_t, audit_session_is_valid, "%" PRIu32, "OBJECT_AUDIT_SESSION");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, o->auditid, uint32_t, audit_session_is_valid, "%" PRIu32, "OBJECT_AUDIT_SESSION");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, o->loginuid, uid_t, uid_is_valid, UID_FMT, "OBJECT_AUDIT_LOGINUID");
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IOVEC_ADD_NUMERIC_FIELD(iovec, n, o->loginuid, uid_t, uid_is_valid, UID_FMT, "OBJECT_AUDIT_LOGINUID");
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