From 0e39139e505a8310ae8530fb2463a9e8f2170d2f Mon Sep 17 00:00:00 2001

From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>

Date: Sat, 24 Sep 2016 21:56:07 +0900

Subject: [PATCH] sysctl: configure kernel parameters in the order they occur

 in each sysctl configuration files (#4205)

Currently, systemd-sysctl command configures kernel parameters in each sysctl

configuration files in random order due to characteristics of iterator of

Hashmap.

However, kernel parameters need to be configured in the order they occur in

each sysctl configuration files.

- For example, consider fs.suid_coredump and kernel.core_pattern. If

  fs.suid_coredump=2 is configured before kernel.core_pattern= whose default

  value is "core", then kernel outputs the following message:

      Unsafe core_pattern used with suid_dumpable=2. Pipe handler or fully qualified core dump path required.

  Note that the security issue mentioned in this message has already been fixed

  on recent kernels, so this is just a warning message on such kernels. But

  it's still confusing to users that this message is output on some boot and

  not output on another boot.

- I don't know but there could be other kernel parameters that are significant

  in the order they are configured.

- The legacy sysctl command configures kernel parameters in the order they

  occur in each sysctl configuration files. Although I didn't find any official

  specification explaining this behavior of sysctl command, I don't think there

  is any meaningful reason to change this behavior, in particular, to the

  random one.

This commit does the change by simply using OrderedHashmap instead of

Hashmap.

(cherry picked from commit 886cf982d3018f7451f0548dadbc05bd2d583bb6)

Resolves: #1382244

---

 src/sysctl/sysctl.c | 20 ++++++++++----------

 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/sysctl/sysctl.c b/src/sysctl/sysctl.c

index 4fb293b9b5..bb2bea7cdf 100644

--- a/src/sysctl/sysctl.c

+++ b/src/sysctl/sysctl.c

@@ -90,14 +90,14 @@ static int apply_sysctl(const char *property, const char *value) {

         return r;

 }

-static int apply_all(Hashmap *sysctl_options) {

-        int r = 0;

+static int apply_all(OrderedHashmap *sysctl_options) {

+        int r;

         char *property, *value;

         Iterator i;

         assert(sysctl_options);

-        HASHMAP_FOREACH_KEY(value, property, sysctl_options, i) {

+        ORDERED_HASHMAP_FOREACH_KEY(value, property, sysctl_options, i) {

                 int k;

                 k = apply_sysctl(property, value);

@@ -107,7 +107,7 @@ static int apply_all(Hashmap *sysctl_options) {

         return r;

 }

-static int parse_file(Hashmap *sysctl_options, const char *path, bool ignore_enoent) {

+static int parse_file(OrderedHashmap *sysctl_options, const char *path, bool ignore_enoent) {

         _cleanup_fclose_ FILE *f = NULL;

         int r;

@@ -171,13 +171,13 @@ static int parse_file(Hashmap *sysctl_options, const char *path, bool ignore_eno

                 }

 found:

-                existing = hashmap_get2(sysctl_options, p, &v);

+                existing = ordered_hashmap_get2(sysctl_options, p, &v);

                 if (existing) {

                         if (streq(value, existing))

                                 continue;

                         log_debug("Overwriting earlier assignment of %s in file '%s'.", p, path);

-                        free(hashmap_remove(sysctl_options, p));

+                        free(ordered_hashmap_remove(sysctl_options, p));

                         free(v);

                 }

@@ -191,7 +191,7 @@ found:

                         return log_oom();

                 }

-                k = hashmap_put(sysctl_options, property, new_value);

+                k = ordered_hashmap_put(sysctl_options, property, new_value);

                 if (k < 0) {

                         log_error_errno(k, "Failed to add sysctl variable %s to hashmap: %m", property);

                         free(property);

@@ -277,7 +277,7 @@ static int parse_argv(int argc, char *argv[]) {

 int main(int argc, char *argv[]) {

         int r = 0, k;

-        Hashmap *sysctl_options;

+        OrderedHashmap *sysctl_options;

         r = parse_argv(argc, argv);

         if (r <= 0)

@@ -289,7 +289,7 @@ int main(int argc, char *argv[]) {

         umask(0022);

-        sysctl_options = hashmap_new(&string_hash_ops);

+        sysctl_options = ordered_hashmap_new(&string_hash_ops);

         if (!sysctl_options) {

                 r = log_oom();

                 goto finish;

@@ -331,7 +331,7 @@ int main(int argc, char *argv[]) {

                 r = k;

 finish:

-        hashmap_free_free_free(sysctl_options);

+        ordered_hashmap_free_free_free(sysctl_options);

         strv_free(arg_prefixes);

         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;