Mercurial > hg > dhcpcd

changeset 5312:b336a280de82 draft

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privsep: Set resource limits when dropping privs Disables forking, new files, sockets and writing large files.
author Roy Marples <roy@marples.name>
date Fri, 05 Jun 2020 12:24:44 +0100
parents fd78486b12a7
children 9aa7c5f01a8b
files src/privsep.c
diffstat 1 files changed, 22 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/src/privsep.c	Fri Jun 05 12:23:51 2020 +0100
+++ b/src/privsep.c	Fri Jun 05 12:24:44 2020 +0100
@@ -39,6 +39,7 @@
  * this in a script or something.
  */
 
+#include <sys/resource.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -112,6 +113,7 @@
 ps_dropprivs(struct dhcpcd_ctx *ctx)
 {
 	struct passwd *pw = ctx->ps_user;
+	struct rlimit rzero = { .rlim_cur = 0, .rlim_max = 0 };
 
 	if (!(ctx->options & DHCPCD_FORKED))
 		logdebugx("chrooting to `%s' as %s", pw->pw_dir, pw->pw_name);
@@ -128,6 +130,26 @@
 		return -1;
 	}
 
+	/* Prohibit new files, sockets, etc */
+	if (setrlimit(RLIMIT_NOFILE, &rzero) == -1) {
+		logerr("setrlimit RLIMIT_NOFILE");
+		return -1;
+	}
+
+	/* Prohibit large files */
+	if (setrlimit(RLIMIT_FSIZE, &rzero) == -1) {
+		logerr("setrlimit RLIMIT_FSIZE");
+		return -1;
+	}
+
+#ifdef RLIMIT_NPROC
+	/* Prohibit forks */
+	if (setrlimit(RLIMIT_NPROC, &rzero) == -1) {
+		logerr("setrlimit RLIMIT_NPROC");
+		return -1;
+	}
+#endif
+
 	return 0;
 }