[hackers] [quark][PATCH] Raise RLIMIT_NPROC only if maxnprocs higher than current limits

From: Armin Friedl <dev_AT_friedl.net>
Date: Mon, 17 Aug 2020 22:55:19 +0200

Currently maxnprocs may actually lower the limit. Especially when using the
default limit of 512, this quickly causes quark's fork() to fail when started
with a non-exclusive user.

To mitigate this, we respect system defaults and only raise the limit if it is
an actual raise.

---
 main.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/main.c b/main.c
index 0542fab..0c43584 100644
--- a/main.c
+++ b/main.c
_AT_@ -285,16 +285,21 @@ main(int argc, char *argv[])
 	}
 
 	/* raise the process limit */
-	rlim.rlim_cur = rlim.rlim_max = maxnprocs;
-	if (setrlimit(RLIMIT_NPROC, &rlim) < 0) {
-		die("setrlimit RLIMIT_NPROC:");
-	}
-
-	/* validate user and group */
-	errno = 0;
-	if (!user || !(pwd = getpwnam(user))) {
-		die("getpwnam '%s': %s", user ? user : "null",
-		    errno ? strerror(errno) : "Entry not found");
+  if (getrlimit(RLIMIT_NPROC, &rlim) < 0) {
+    die("getrlimit RLIMIT_NPROC:");
+  }
+
+  rlim.rlim_cur = MAX(rlim.rlim_cur, maxnprocs);
+  rlim.rlim_max = MAX(rlim.rlim_max, maxnprocs);
+  if (setrlimit(RLIMIT_NPROC, &rlim) < 0) {
+    die("setrlimit RLIMIT_NPROC:");
+  }
+
+  /* validate user and group */
+  errno = 0;
+  if (!user || !(pwd = getpwnam(user))) {
+    die("getpwnam '%s': %s", user ? user : "null",
+        errno ? strerror(errno) : "Entry not found");
 	}
 	errno = 0;
 	if (!group || !(grp = getgrnam(group))) {
-- 
2.26.2

Received on Mon Aug 17 2020 - 22:55:19 CEST