From 88bef035149080be5a83f90d91d5b13cec9749e8 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>

Date: Fri, 11 Oct 2013 19:33:13 -0400

Subject: [PATCH] Never call qsort on potentially NULL arrays

This extends 62678ded 'efi: never call qsort on potentially

NULL arrays' to all other places where qsort is used and it

is not obvious that the count is non-zero.

---

 src/analyze/systemd-analyze.c     |  2 +-

 src/cgtop/cgtop.c                 |  2 +-

 src/core/namespace.c              | 38 ++++++++++++++++++++------------------

 src/journal/catalog.c             |  2 +-

 src/journal/journal-file.c        |  2 +-

 src/journal/journal-vacuum.c      |  3 +--

 src/journal/journalctl.c          |  2 +-

 src/libsystemd-bus/bus-match.c    |  2 +-

 src/libudev/libudev-enumerate.c   |  2 +-

 src/nss-myhostname/netlink.c      |  3 ++-

 src/readahead/readahead-collect.c | 39 ++++++++++++++++++++++-----------------

 src/shared/cgroup-show.c          |  2 ++

 src/shared/conf-files.c           |  2 +-

 src/shared/efivars.c              |  3 +--

 src/shared/fileio.c               |  1 +

 src/shared/util.h                 | 12 ++++++++++++

 src/systemctl/systemctl.c         | 10 +++++-----

 17 files changed, 74 insertions(+), 53 deletions(-)

diff --git a/src/analyze/systemd-analyze.c b/src/analyze/systemd-analyze.c

index 27d063c..a4f15eb 100644

--- a/src/analyze/systemd-analyze.c

+++ b/src/analyze/systemd-analyze.c

@@ -768,7 +768,7 @@ static int list_dependencies_one(DBusConnection *bus, const char *name, unsigned

         if (r < 0)

                 return r;

-        qsort(deps, strv_length(deps), sizeof (char*), list_dependencies_compare);

+        qsort_safe(deps, strv_length(deps), sizeof (char*), list_dependencies_compare);

         r = acquire_boot_times(bus, &boot);

         if (r < 0)

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

index cacf705..293a211 100644

--- a/src/cgtop/cgtop.c

+++ b/src/cgtop/cgtop.c

@@ -461,7 +461,7 @@ static int display(Hashmap *a) {

                 if (g->n_tasks_valid || g->cpu_valid || g->memory_valid || g->io_valid)

                         array[n++] = g;

-        qsort(array, n, sizeof(Group*), group_compare);

+        qsort_safe(array, n, sizeof(Group*), group_compare);

         /* Find the longest names in one run */

         for (j = 0; j < n; j++) {

diff --git a/src/core/namespace.c b/src/core/namespace.c

index 16b132b..936f368 100644

--- a/src/core/namespace.c

+++ b/src/core/namespace.c

@@ -222,7 +222,7 @@ int setup_namespace(char** read_write_dirs,

                      strv_length(read_only_dirs) +

                      strv_length(inaccessible_dirs) +

                      (private_tmp ? 2 : 0);

-        BindMount *m, *mounts;

+        BindMount *m, *mounts = NULL;

         int r = 0;

         if (!mount_flags)

@@ -231,27 +231,29 @@ int setup_namespace(char** read_write_dirs,

         if (unshare(CLONE_NEWNS) < 0)

                 return -errno;

-        m = mounts = (BindMount *) alloca(n * sizeof(BindMount));

-        if ((r = append_mounts(&m, read_write_dirs, READWRITE)) < 0 ||

-                (r = append_mounts(&m, read_only_dirs, READONLY)) < 0 ||

-                (r = append_mounts(&m, inaccessible_dirs, INACCESSIBLE)) < 0)

-                return r;

+        if (n) {

+                m = mounts = (BindMount *) alloca(n * sizeof(BindMount));

+                if ((r = append_mounts(&m, read_write_dirs, READWRITE)) < 0 ||

+                    (r = append_mounts(&m, read_only_dirs, READONLY)) < 0 ||

+                    (r = append_mounts(&m, inaccessible_dirs, INACCESSIBLE)) < 0)

+                        return r;

+

+                if (private_tmp) {

+                        m->path = "/tmp";

+                        m->mode = PRIVATE_TMP;

+                        m++;

+

+                        m->path = "/var/tmp";

+                        m->mode = PRIVATE_VAR_TMP;

+                        m++;

+                }

-        if (private_tmp) {

-                m->path = "/tmp";

-                m->mode = PRIVATE_TMP;

-                m++;

+                assert(mounts + n == m);

-                m->path = "/var/tmp";

-                m->mode = PRIVATE_VAR_TMP;

-                m++;

+                qsort(mounts, n, sizeof(BindMount), mount_path_compare);

+                drop_duplicates(mounts, &n);

         }

-        assert(mounts + n == m);

-

-        qsort(mounts, n, sizeof(BindMount), mount_path_compare);

-        drop_duplicates(mounts, &n);

-

         /* Remount / as SLAVE so that nothing now mounted in the namespace

            shows up in the parent */

         if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0)

diff --git a/src/journal/catalog.c b/src/journal/catalog.c

index 7738d24..90ca008 100644

--- a/src/journal/catalog.c

+++ b/src/journal/catalog.c

@@ -399,7 +399,7 @@ int catalog_update(const char* database, const char* root, const char* const* di

         }

         assert(n == hashmap_size(h));

-        qsort(items, n, sizeof(CatalogItem), catalog_compare_func);

+        qsort_safe(items, n, sizeof(CatalogItem), catalog_compare_func);

         r = write_catalog(database, h, sb, items, n);

         if (r < 0)

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c

index 81c344f..425e38a 100644

--- a/src/journal/journal-file.c

+++ b/src/journal/journal-file.c

@@ -1344,7 +1344,7 @@ int journal_file_append_entry(JournalFile *f, const dual_timestamp *ts, const st

         /* Order by the position on disk, in order to improve seek

          * times for rotating media. */

-        qsort(items, n_iovec, sizeof(EntryItem), entry_item_cmp);

+        qsort_safe(items, n_iovec, sizeof(EntryItem), entry_item_cmp);

         r = journal_file_append_entry_internal(f, ts, xor_hash, items, n_iovec, seqnum, ret, offset);

diff --git a/src/journal/journal-vacuum.c b/src/journal/journal-vacuum.c

index 8d5effb..d4a1c6c 100644

--- a/src/journal/journal-vacuum.c

+++ b/src/journal/journal-vacuum.c

@@ -299,8 +299,7 @@ int journal_directory_vacuum(

                 n_list ++;

         }

-        if (n_list > 0)

-                qsort(list, n_list, sizeof(struct vacuum_info), vacuum_compare);

+        qsort_safe(list, n_list, sizeof(struct vacuum_info), vacuum_compare);

         for (i = 0; i < n_list; i++) {

                 struct statvfs ss;

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c

index 9a2d255..0876ee6 100644

--- a/src/journal/journalctl.c

+++ b/src/journal/journalctl.c

@@ -755,7 +755,7 @@ static int get_relative_boot_id(sd_journal *j, sd_id128_t *boot_id, int relative

                 sd_journal_flush_matches(j);

         }

-        qsort(all_ids, count, sizeof(boot_id_t), boot_id_cmp);

+        qsort_safe(all_ids, count, sizeof(boot_id_t), boot_id_cmp);

         if (sd_id128_equal(*boot_id, SD_ID128_NULL)) {

                 if (relative > (int) count || relative <= -(int)count)

diff --git a/src/libsystemd-bus/bus-match.c b/src/libsystemd-bus/bus-match.c

index 1411167..916682a 100644

--- a/src/libsystemd-bus/bus-match.c

+++ b/src/libsystemd-bus/bus-match.c

@@ -768,7 +768,7 @@ int bus_match_parse(

         }

         /* Order the whole thing, so that we always generate the same tree */

-        qsort(components, n_components, sizeof(struct bus_match_component), match_component_compare);

+        qsort_safe(components, n_components, sizeof(struct bus_match_component), match_component_compare);

         /* Check for duplicates */

         for (i = 0; i+1 < n_components; i++)

diff --git a/src/libudev/libudev-enumerate.c b/src/libudev/libudev-enumerate.c

index 8146f27..e71d766 100644

--- a/src/libudev/libudev-enumerate.c

+++ b/src/libudev/libudev-enumerate.c

@@ -276,7 +276,7 @@ _public_ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enume

                 size_t move_later_prefix = 0;

                 udev_list_cleanup(&udev_enumerate->devices_list);

-                qsort(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);

+                qsort_safe(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);

                 max = udev_enumerate->devices_cur;

                 for (i = 0; i < max; i++) {

diff --git a/src/nss-myhostname/netlink.c b/src/nss-myhostname/netlink.c

index b1ef912..47a41f5 100644

--- a/src/nss-myhostname/netlink.c

+++ b/src/nss-myhostname/netlink.c

@@ -197,7 +197,8 @@ finish:

                 return r;

         }

-        qsort(list, n_list, sizeof(struct address), address_compare);

+        if (n_list)

+                qsort(list, n_list, sizeof(struct address), address_compare);

         *_list = list;

         *_n_list = n_list;

diff --git a/src/readahead/readahead-collect.c b/src/readahead/readahead-collect.c

index 32888ad..6b74866 100644

--- a/src/readahead/readahead-collect.c

+++ b/src/readahead/readahead-collect.c

@@ -536,8 +536,7 @@ done:

                 HASHMAP_FOREACH_KEY(q, p, files, i)

                         pack_file(pack, p, on_btrfs);

         } else {

-                struct item *ordered, *j;

-                unsigned k, n;

+                unsigned n;

                 /* On rotating media, order things by the block

                  * numbers */

@@ -545,25 +544,31 @@ done:

                 log_debug("Ordering...");

                 n = hashmap_size(files);

-                if (!(ordered = new(struct item, n))) {

-                        r = log_oom();

-                        goto finish;

-                }

-

-                j = ordered;

-                HASHMAP_FOREACH_KEY(q, p, files, i) {

-                        memcpy(j, q, sizeof(struct item));

-                        j++;

-                }

+                if (n) {

+                        _cleanup_free_ struct item *ordered;

+                        struct item *j;

+                        unsigned k;

+

+                        ordered = new(struct item, n);

+                        if (!ordered) {

+                                r = log_oom();

+                                goto finish;

+                        }

-                assert(ordered + n == j);

+                        j = ordered;

+                        HASHMAP_FOREACH_KEY(q, p, files, i) {

+                                memcpy(j, q, sizeof(struct item));

+                                j++;

+                        }

-                qsort(ordered, n, sizeof(struct item), qsort_compare);

+                        assert(ordered + n == j);

-                for (k = 0; k < n; k++)

-                        pack_file(pack, ordered[k].path, on_btrfs);

+                        qsort(ordered, n, sizeof(struct item), qsort_compare);

-                free(ordered);

+                        for (k = 0; k < n; k++)

+                                pack_file(pack, ordered[k].path, on_btrfs);

+                } else

+                        log_warning("No pack files");

         }

         log_debug("Finalizing...");

diff --git a/src/shared/cgroup-show.c b/src/shared/cgroup-show.c

index e971f36..cc44ab4 100644

--- a/src/shared/cgroup-show.c

+++ b/src/shared/cgroup-show.c

@@ -44,6 +44,8 @@ static void show_pid_array(int pids[], unsigned n_pids, const char *prefix, unsi

         unsigned i, m, pid_width;

         pid_t biggest = 0;

+        assert(n_pids > 0);

+

         /* Filter duplicates */

         m = 0;

         for (i = 0; i < n_pids; i++) {

diff --git a/src/shared/conf-files.c b/src/shared/conf-files.c

index 6d99739..ed4070c 100644

--- a/src/shared/conf-files.c

+++ b/src/shared/conf-files.c

@@ -127,7 +127,7 @@ static int conf_files_list_strv_internal(char ***strv, const char *suffix, const

                 return -ENOMEM;

         }

-        qsort(files, hashmap_size(fh), sizeof(char *), base_cmp);

+        qsort_safe(files, hashmap_size(fh), sizeof(char *), base_cmp);

         *strv = files;

         hashmap_free(fh);

diff --git a/src/shared/efivars.c b/src/shared/efivars.c

index c015b16..f3eb6a6 100644

--- a/src/shared/efivars.c

+++ b/src/shared/efivars.c

@@ -384,8 +384,7 @@ int efi_get_boot_options(uint16_t **options) {

                 list[count ++] = id;

         }

-        if (list)

-                qsort(list, count, sizeof(uint16_t), cmp_uint16);

+        qsort_safe(list, count, sizeof(uint16_t), cmp_uint16);

         *options = list;

         return count;

diff --git a/src/shared/fileio.c b/src/shared/fileio.c

index 603a1c7..733b320 100644

--- a/src/shared/fileio.c

+++ b/src/shared/fileio.c

@@ -662,6 +662,7 @@ int get_status_field(const char *filename, const char *pattern, char **field) {

         int r;

         assert(filename);

+        assert(pattern);

         assert(field);

         r = read_full_file(filename, &status, NULL);

diff --git a/src/shared/util.h b/src/shared/util.h

index 1b845b3..222abe0 100644

--- a/src/shared/util.h

+++ b/src/shared/util.h

@@ -764,3 +764,15 @@ bool id128_is_valid(const char *s) _pure_;

 void parse_user_at_host(char *arg, char **user, char **host);

 int split_pair(const char *s, const char *sep, char **l, char **r);

+

+/**

+ * Normal qsort requires base to be nonnull. Here were require

+ * that only if nmemb > 0.

+ */

+static inline void qsort_safe(void *base, size_t nmemb, size_t size,

+                              int (*compar)(const void *, const void *)) {

+        if (nmemb) {

+                assert(base);

+                qsort(base, nmemb, size, compar);

+        }

+}

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

index d75281f..036828b 100644

--- a/src/systemctl/systemctl.c

+++ b/src/systemctl/systemctl.c

@@ -471,7 +471,7 @@ static int list_units(DBusConnection *bus, char **args) {

         if (r < 0)

                 return r;

-        qsort(unit_infos, c, sizeof(struct unit_info), compare_unit_info);

+        qsort_safe(unit_infos, c, sizeof(struct unit_info), compare_unit_info);

         output_units_list(unit_infos, c);

@@ -733,8 +733,8 @@ static int list_sockets(DBusConnection *bus, char **args) {

                 listen = triggered = NULL; /* avoid cleanup */

         }

-        qsort(socket_infos, cs, sizeof(struct socket_info),

-              (__compar_fn_t) socket_info_compare);

+        qsort_safe(socket_infos, cs, sizeof(struct socket_info),

+                   (__compar_fn_t) socket_info_compare);

         output_sockets_list(socket_infos, cs);

@@ -1108,7 +1108,7 @@ static int list_dependencies_one(DBusConnection *bus, const char *name, int leve

         if (r < 0)

                 return r;

-        qsort(deps, strv_length(deps), sizeof (char*), list_dependencies_compare);

+        qsort_safe(deps, strv_length(deps), sizeof (char*), list_dependencies_compare);

         STRV_FOREACH(c, deps) {

                 if (strv_contains(u, *c)) {

@@ -3532,7 +3532,7 @@ static int show_all(const char* verb,

         if (r < 0)

                 return r;

-        qsort(unit_infos, c, sizeof(struct unit_info), compare_unit_info);

+        qsort_safe(unit_infos, c, sizeof(struct unit_info), compare_unit_info);

         for (u = unit_infos; u < unit_infos + c; u++) {

                 _cleanup_free_ char *p = NULL;