many: more checks for pointer access without NULL check (#41370)

This is a followup for https://github.com/systemd/systemd/pull/41096
that makes more subsystems pass the new `check-pointer-deref` coccinelle
checks. See the individual commits.

My plan is to do a few more of these PRs until we have it all covered. I
could also do it in a single very big PR but I'm worried about a)
conflicts b) that its just too big/annoying to review. Only 7 dirs left
but some (like src/basic) are quite big (~50k loc) so those PRs will be
a bit bigger.

coccinelle/check-pointer-deref.cocci

@@ -13,6 +13,7 @@
  */
 @@
 identifier fn, param;
+identifier is_set =~ "_is_set$";
 type T;
 position p;
 @@
@@ -25,10 +26,12 @@ fn(..., T *param, ...) {
       when != assert_return(param, ...)
       when != ASSERT_PTR(param)
       when != POINTER_MAY_BE_NULL(param)
-      /* NULL-safe helpers used commonly enough in assert() to warrant inclusion
-       * here. For less common cases, use POINTER_MAY_BE_NULL(param) instead of
-       * extending this list. */
-      when != assert(pidref_is_set(param))
+      /* Any foo_is_set(param) guard implies param != NULL, since all *_is_set()
+       * helpers in systemd return false for NULL input. Note the is_set regex
+       * in identifier. */
+      when != assert(is_set(param))
+      when != assert_return(is_set(param), ...)
+      when != \( is_set(param) \)
       when != \( param == NULL \| param != NULL \| !param \)
 * *param@p
   ...

meson.build

@@ -2979,16 +2979,14 @@ if spatch.found()
         coccinelle_exclude = [
                 'src/basic/',
                 'src/core/',
-                'src/import/',
                 'src/journal/',
-                'src/libc/',
                 'src/libsystemd/',
-                'src/libsystemd-network/',
                 'src/network/',
                 'src/nspawn/',
-                'src/nss-systemd/',
-                'src/resolve/',
                 'src/shared/',
+                # libc/ has no assert() or systemd-headers so leave it
+                'src/libc/',
+                # test/ has some deliberate wonky pointers, just leave excluded
                 'src/test/',
         ]
 

src/boot/initrd.c

@@ -74,7 +74,6 @@ EFI_STATUS initrd_register(
         EFI_HANDLE handle;
         struct initrd_loader *loader;
 
-        POINTER_MAY_BE_NULL(initrd);
         assert(ret_initrd_handle);
 
         /* If no initrd is specified we'll not install any. This avoids registration of the protocol for that

src/import/curl-util.c

@@ -359,6 +359,8 @@ int curl_header_strdup(const void *contents, size_t sz, const char *field, char
         const char *p;
         char *s;
 
+        assert(value);
+
         p = memory_startswith_no_case(contents, sz, field);
         if (!p)
                 return 0;

src/import/import-compress.c

@@ -318,6 +318,10 @@ static int enlarge_buffer(void **buffer, size_t *buffer_size, size_t *buffer_all
         size_t l;
         void *p;
 
+        assert(buffer);
+        assert(buffer_size);
+        assert(buffer_allocated);
+
         if (*buffer_allocated > *buffer_size)
                 return 0;
 

src/import/pull-common.c

@@ -622,6 +622,7 @@ int pull_job_restart_with_sha256sum(PullJob *j, char **ret) {
         int r;
 
         assert(j);
+        assert(ret);
 
         /* Generic implementation of a PullJobNotFound handler, that restarts the job requesting SHA256SUMS */
 

src/import/qcow2-util.c

@@ -150,6 +150,10 @@ static int normalize_offset(
                 bool *compressed,
                 uint64_t *compressed_size) {
 
+        assert(ret);
+        POINTER_MAY_BE_NULL(compressed);
+        POINTER_MAY_BE_NULL(compressed_size);
+
         uint64_t q;
 
         q = be64toh(p);

src/libsystemd-network/dhcp6-option.c

@@ -250,6 +250,8 @@ int dhcp6_option_append(
 
         int r;
 
+        assert(buf);
+        assert(offset);
         assert(optval || optlen == 0);
 
         r = option_append_hdr(buf, offset, code, optlen);

src/libsystemd-network/lldp-neighbor.c

@@ -408,6 +408,7 @@ static int format_mac_address(const void *data, size_t sz, char **ret) {
         char *k;
 
         assert(data || sz <= 0);
+        assert(ret);
 
         if (sz != 7)
                 return 0;

src/libsystemd-network/sd-dhcp-client.c

@@ -776,6 +776,9 @@ static usec_t client_compute_reacquisition_timeout(usec_t now_usec, usec_t expir
 }
 
 static int cmp_uint8(const uint8_t *a, const uint8_t *b) {
+        assert(a);
+        assert(b);
+
         return CMP(*a, *b);
 }
 

src/libsystemd-network/sd-dhcp-lease.c

@@ -1266,6 +1266,8 @@ int dhcp_lease_insert_private_option(sd_dhcp_lease *lease, uint8_t tag, const vo
 int dhcp_lease_new(sd_dhcp_lease **ret) {
         sd_dhcp_lease *lease;
 
+        assert(ret);
+
         lease = new0(sd_dhcp_lease, 1);
         if (!lease)
                 return -ENOMEM;

src/libsystemd-network/sd-dhcp-server.c

@@ -1641,6 +1641,7 @@ int sd_dhcp_server_set_callback(sd_dhcp_server *server, sd_dhcp_server_callback_
 
 int sd_dhcp_server_set_relay_target(sd_dhcp_server *server, const struct in_addr *address) {
         assert_return(server, -EINVAL);
+        assert_return(address, -EINVAL);
         assert_return(!sd_dhcp_server_is_running(server), -EBUSY);
 
         if (memcmp(address, &server->relay_target, sizeof(struct in_addr)) == 0)

src/libsystemd-network/sd-dhcp6-client.c

@@ -379,6 +379,9 @@ int sd_dhcp6_client_get_information_request(sd_dhcp6_client *client, int *enable
 }
 
 static int be16_compare_func(const be16_t *a, const be16_t *b) {
+        assert(a);
+        assert(b);
+
         return CMP(be16toh(*a), be16toh(*b));
 }
 

src/libsystemd-network/sd-lldp-tx.c

@@ -157,6 +157,7 @@ int sd_lldp_tx_set_multicast_mode(sd_lldp_tx *lldp_tx, sd_lldp_multicast_mode_t
 
 int sd_lldp_tx_set_hwaddr(sd_lldp_tx *lldp_tx, const struct ether_addr *hwaddr) {
         assert_return(lldp_tx, -EINVAL);
+        assert_return(hwaddr, -EINVAL);
         assert_return(!ether_addr_is_null(hwaddr), -EINVAL);
 
         lldp_tx->hwaddr = *hwaddr;

src/libsystemd-network/test-dhcp-option.c

@@ -120,6 +120,9 @@ static DHCPMessage *create_message(uint8_t *options, uint16_t optlen,
 }
 
 static void test_ignore_opts(uint8_t *descoption, int *descpos, int *desclen) {
+        assert(descoption);
+        assert(descpos);
+        assert(desclen);
         assert_se(*descpos >= 0);
 
         while (*descpos < *desclen) {

src/libsystemd-network/test-lldp-rx.c

@@ -35,6 +35,8 @@ static void lldp_rx_handler(sd_lldp_rx *lldp_rx, sd_lldp_rx_event_t event, sd_ll
 static int start_lldp_rx(sd_lldp_rx **lldp_rx, sd_event *e, sd_lldp_rx_callback_t cb, void *cb_data) {
         int r;
 
+        assert(lldp_rx);
+
         r = sd_lldp_rx_new(lldp_rx);
         if (r < 0)
                 return r;

src/nss-systemd/nss-systemd.c

@@ -149,6 +149,7 @@ static enum nss_status copy_synthesized_passwd(
 
         assert(dest);
         assert(src);
+        assert(errnop);
         assert(src->pw_name);
         assert(src->pw_passwd);
         assert(src->pw_gecos);
@@ -191,6 +192,7 @@ static enum nss_status copy_synthesized_spwd(
 
         assert(dest);
         assert(src);
+        assert(errnop);
         assert(src->sp_namp);
         assert(src->sp_pwdp);
 
@@ -223,6 +225,7 @@ static enum nss_status copy_synthesized_group(
 
         assert(dest);
         assert(src);
+        assert(errnop);
         assert(src->gr_name);
         assert(src->gr_passwd);
         assert(src->gr_mem);
@@ -259,6 +262,7 @@ static enum nss_status copy_synthesized_sgrp(
 
         assert(dest);
         assert(src);
+        assert(errnop);
         assert(src->sg_namp);
         assert(src->sg_passwd);
         assert(src->sg_adm);

src/nss-systemd/userdb-glue.c

@@ -415,6 +415,9 @@ enum nss_status userdb_getgrgid(
  * string vector strv and stores amount of pointers in n and total
  * length of all contained strings including NUL bytes in len. */
 static void nss_count_strv(char * const *strv, size_t *n, size_t *len) {
+        assert(n);
+        assert(len);
+
         STRV_FOREACH(str, strv) {
                 (*len) += sizeof(char*);  /* space for array entry */
                 (*len) += strlen(*str) + 1;

src/resolve/resolved-dns-dnssec.c

@@ -48,7 +48,7 @@ REENABLE_WARNING;
 #if HAVE_OPENSSL
 
 static int rr_compare(DnsResourceRecord * const *a, DnsResourceRecord * const *b) {
-        const DnsResourceRecord *x = *a, *y = *b;
+        const DnsResourceRecord *x = *ASSERT_PTR(a), *y = *ASSERT_PTR(b);
         size_t m;
         int r;
 

src/resolve/resolved-dns-stub.c

@@ -81,6 +81,8 @@ int dns_stub_listener_extra_new(
                 Manager *m,
                 DnsStubListenerExtra **ret) {
 
+        assert(ret);
+
         DnsStubListenerExtra *l;
 
         l = new(DnsStubListenerExtra, 1);

src/resolve/resolved-dnssd.c

@@ -332,6 +332,8 @@ int dnssd_txt_item_new_from_string(const char *key, const char *value, DnsTxtIte
         size_t length;
         DnsTxtItem *i;
 
+        assert(ret_item);
+
         length = strlen(key);
 
         if (!isempty(value))
@@ -357,6 +359,8 @@ int dnssd_txt_item_new_from_data(const char *key, const void *data, const size_t
         size_t length;
         DnsTxtItem *i;
 
+        assert(ret_item);
+
         length = strlen(key);
 
         if (size > 0)

src/resolve/resolved-link.c

@@ -890,6 +890,7 @@ int link_address_new(Link *l,
 
         assert(l);
         assert(in_addr);
+        assert(in_addr_broadcast);
 
         a = new(LinkAddress, 1);
         if (!a)

src/resolve/resolved-manager.c

@@ -1464,6 +1464,8 @@ static int manager_next_random_name(const char *old, char **ret_new) {
         uint64_t u, a;
         char *n;
 
+        assert(ret_new);
+
         p = strchr(old, 0);
         assert(p);
 

src/resolve/test-dns-zone.c

@@ -10,6 +10,8 @@
 #include "tests.h"
 
 static void dns_scope_freep(DnsScope **s) {
+        POINTER_MAY_BE_NULL(s);
+
         if (s != NULL && *s != NULL)
                 dns_scope_free(*s);
 }