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main: bump RLIMIT_NOFILE for the root user substantially

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On current kernels BPF_MAP_TYPE_LPM_TRIE bpf maps are charged against
RLIMIT_MEMLOCK even for privileged users that have CAP_IPC_LOCK. Given
that mlock() generally ignores RLIMIT_MEMLOCK if CAP_IPC_LOCK is set
this appears to be an oversight in the kernel. Either way, until that's
fixed, let's just bump RLIMIT_MEMLOCK for the root user considerably, as
the default is quite limiting, and doesn't permit us to create more than
a few TRIE maps.
This commit is contained in:
Lennart Poettering 2017-09-21 19:43:07 +02:00
parent c4ad3f43ef
commit fb3ae275cb
1 changed files with 26 additions and 2 deletions
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28
src/core/main.c
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@ -1205,6 +1205,26 @@ static int bump_rlimit_nofile(struct rlimit *saved_rlimit) {
return 0;
}
static int bump_rlimit_memlock(struct rlimit *saved_rlimit) {
int r;
assert(saved_rlimit);
assert(getuid() == 0);
/* BPF_MAP_TYPE_LPM_TRIE bpf maps are charged against RLIMIT_MEMLOCK, even though we have CAP_IPC_LOCK which
* should normally disable such checks. We need them to implement IPAccessAllow= and IPAccessDeny=, hence let's
* bump the value high enough for the root user. */
if (getrlimit(RLIMIT_MEMLOCK, saved_rlimit) < 0)
return log_warning_errno(errno, "Reading RLIMIT_MEMLOCK failed, ignoring: %m");
r = setrlimit_closest(RLIMIT_MEMLOCK, &RLIMIT_MAKE_CONST(1024ULL*1024ULL*16ULL));
if (r < 0)
return log_warning_errno(r, "Setting RLIMIT_MEMLOCK failed, ignoring: %m");
return 0;
}
static void test_usr(void) {
/* Check that /usr is not a separate fs */
@ -1388,7 +1408,7 @@ int main(int argc, char *argv[]) {
bool queue_default_job = false;
bool empty_etc = false;
char *switch_root_dir = NULL, *switch_root_init = NULL;
struct rlimit saved_rlimit_nofile = RLIMIT_MAKE_CONST(0);
struct rlimit saved_rlimit_nofile = RLIMIT_MAKE_CONST(0), saved_rlimit_memlock = RLIMIT_MAKE_CONST((rlim_t) -1);
const char *error_message = NULL;
#ifdef HAVE_SYSV_COMPAT
@ -1815,9 +1835,11 @@ int main(int argc, char *argv[]) {
if (prctl(PR_SET_CHILD_SUBREAPER, 1) < 0)
log_warning_errno(errno, "Failed to make us a subreaper: %m");
if (arg_system)
if (arg_system) {
/* Bump up RLIMIT_NOFILE for systemd itself */
(void) bump_rlimit_nofile(&saved_rlimit_nofile);
(void) bump_rlimit_memlock(&saved_rlimit_memlock);
}
}
r = manager_new(arg_system ? UNIT_FILE_SYSTEM : UNIT_FILE_USER,
@ -2051,6 +2073,8 @@ finish:
* its child processes */
if (saved_rlimit_nofile.rlim_cur > 0)
(void) setrlimit(RLIMIT_NOFILE, &saved_rlimit_nofile);
if (saved_rlimit_memlock.rlim_cur != (rlim_t) -1)
(void) setrlimit(RLIMIT_MEMLOCK, &saved_rlimit_memlock);
if (switch_root_dir) {
/* Kill all remaining processes from the