alloc-util: make mfree() typesafe

Make sure we return the same type as we accept.

One incorrect use of mfree() is discovered and fixed this way.

src/basic/alloc-util.h

@@ -44,10 +44,11 @@ typedef void (*free_func_t)(void *p);
 
 #define malloc0(n) (calloc(1, (n) ?: 1))
 
-static inline void *mfree(void *memory) {
-        free(memory);
-        return NULL;
-}
+#define mfree(memory)                           \
+        ({                                      \
+                free(memory);                   \
+                (typeof(memory)) NULL;          \
+        })
 
 #define free_and_replace(a, b)                  \
         ({                                      \

src/basic/memory-util.h

@@ -71,6 +71,16 @@ static inline void *memmem_safe(const void *haystack, size_t haystacklen, const
         return memmem(haystack, haystacklen, needle, needlelen);
 }
 
+static inline void *mempmem_safe(const void *haystack, size_t haystacklen, const void *needle, size_t needlelen) {
+        const uint8_t *p;
+
+        p = memmem_safe(haystack, haystacklen, needle, needlelen);
+        if (!p)
+                return NULL;
+
+        return (uint8_t*) p + needlelen;
+}
+
 #if HAVE_EXPLICIT_BZERO
 static inline void* explicit_bzero_safe(void *p, size_t l) {
         if (l > 0)

src/boot/bootctl.c

@@ -159,12 +159,11 @@ static int get_file_version(int fd, char **v) {
         if (buf == MAP_FAILED)
                 return log_error_errno(errno, "Failed to memory map EFI binary: %m");
 
-        s = memmem(buf, st.st_size - 8, "#### LoaderInfo: ", 17);
+        s = mempmem_safe(buf, st.st_size - 8, "#### LoaderInfo: ", 17);
         if (!s)
                 goto finish;
-        s += 17;
 
-        e = memmem(s, st.st_size - (s - buf), " ####", 5);
+        e = memmem_safe(s, st.st_size - (s - buf), " ####", 5);
         if (!e || e - s < 3) {
                 r = log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Malformed version string.");
                 goto finish;

src/core/unit.c

@@ -5497,10 +5497,19 @@ const char *unit_label_path(const Unit *u) {
         /* Returns the file system path to use for MAC access decisions, i.e. the file to read the SELinux label off
          * when validating access checks. */
 
+        if (IN_SET(u->load_state, UNIT_MASKED, UNIT_NOT_FOUND, UNIT_MERGED))
+                return NULL; /* Shortcut things if we know there is no real, relevant unit file around */
+
         p = u->source_path ?: u->fragment_path;
         if (!p)
                 return NULL;
 
+        if (IN_SET(u->load_state, UNIT_LOADED, UNIT_BAD_SETTING, UNIT_ERROR))
+                return p; /* Shortcut things, if we successfully loaded at least some stuff from the unit file */
+
+        /* Not loaded yet, we need to go to disk */
+        assert(u->load_state == UNIT_STUB);
+
         /* If a unit is masked, then don't read the SELinux label of /dev/null, as that really makes no sense */
         if (null_or_empty_path(p) > 0)
                 return NULL;

src/import/pull-common.c

@@ -10,6 +10,7 @@
 #include "escape.h"
 #include "fd-util.h"
 #include "io-util.h"
+#include "memory-util.h"
 #include "path-util.h"
 #include "process-util.h"
 #include "pull-common.h"
@@ -342,18 +343,18 @@ static int verify_one(PullJob *checksum_job, PullJob *job) {
 
         line = strjoina(job->checksum, " *", fn, "\n");
 
-        p = memmem(checksum_job->payload,
-                   checksum_job->payload_size,
-                   line,
-                   strlen(line));
+        p = memmem_safe(checksum_job->payload,
+                        checksum_job->payload_size,
+                        line,
+                        strlen(line));
 
         if (!p) {
                 line = strjoina(job->checksum, "  ", fn, "\n");
 
-                p = memmem(checksum_job->payload,
-                        checksum_job->payload_size,
-                        line,
-                        strlen(line));
+                p = memmem_safe(checksum_job->payload,
+                                checksum_job->payload_size,
+                                line,
+                                strlen(line));
         }
 
         if (!p || (p != (char*) checksum_job->payload && p[-1] != '\n'))

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

@@ -1134,30 +1134,24 @@ static int client_parse_message(
 
                 switch (optcode) {
                 case SD_DHCP6_OPTION_CLIENTID:
-                        if (clientid) {
-                                log_dhcp6_client(client, "%s contains multiple clientids",
-                                                 dhcp6_message_type_to_string(message->type));
-                                return -EINVAL;
-                        }
+                        if (clientid)
+                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "%s contains multiple clientids",
+                                                              dhcp6_message_type_to_string(message->type));
 
                         if (optlen != client->duid_len ||
-                            memcmp(&client->duid, optval, optlen) != 0) {
-                                log_dhcp6_client(client, "%s DUID does not match",
-                                                 dhcp6_message_type_to_string(message->type));
+                            memcmp(&client->duid, optval, optlen) != 0)
+                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "%s DUID does not match",
+                                                              dhcp6_message_type_to_string(message->type));
 
-                                return -EINVAL;
-                        }
                         clientid = true;
 
                         break;
 
                 case SD_DHCP6_OPTION_SERVERID:
                         r = dhcp6_lease_get_serverid(lease, NULL, NULL);
-                        if (r >= 0) {
-                                log_dhcp6_client(client, "%s contains multiple serverids",
-                                                 dhcp6_message_type_to_string(message->type));
-                                return -EINVAL;
-                        }
+                        if (r >= 0)
+                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "%s contains multiple serverids",
+                                                              dhcp6_message_type_to_string(message->type));
 
                         r = dhcp6_lease_set_serverid(lease, optval, optlen);
                         if (r < 0)
@@ -1180,20 +1174,16 @@ static int client_parse_message(
                         if (status < 0)
                                 return status;
 
-                        if (status > 0) {
-                                log_dhcp6_client(client, "%s Status %s",
-                                                 dhcp6_message_type_to_string(message->type),
-                                                 dhcp6_message_status_to_string(status));
-
-                                return -EINVAL;
-                        }
+                        if (status > 0)
+                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "%s Status %s",
+                                                              dhcp6_message_type_to_string(message->type),
+                                                              dhcp6_message_status_to_string(status));
 
                         break;
 
                 case SD_DHCP6_OPTION_IA_NA:
                         if (client->state == DHCP6_STATE_INFORMATION_REQUEST) {
-                                log_dhcp6_client(client, "Information request ignoring IA NA option");
-
+                                log_dhcp6_client(client, "Ignoring IA NA option in information requesting mode.");
                                 break;
                         }
 
@@ -1210,23 +1200,20 @@ static int client_parse_message(
                         if (r < 0)
                                 return r;
 
-                        if (client->ia_na.ia_na.id != iaid_lease) {
-                                log_dhcp6_client(client, "%s has wrong IAID for IA NA",
-                                                 dhcp6_message_type_to_string(message->type));
-                                return -EINVAL;
-                        }
+                        if (client->ia_na.ia_na.id != iaid_lease)
+                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "%s has wrong IAID for IA NA",
+                                                              dhcp6_message_type_to_string(message->type));
 
                         if (lease->ia.addresses) {
                                 lt_t1 = MIN(lt_t1, be32toh(lease->ia.ia_na.lifetime_t1));
-                                lt_t2 = MIN(lt_t2, be32toh(lease->ia.ia_na.lifetime_t1));
+                                lt_t2 = MIN(lt_t2, be32toh(lease->ia.ia_na.lifetime_t2));
                         }
 
                         break;
 
                 case SD_DHCP6_OPTION_IA_PD:
                         if (client->state == DHCP6_STATE_INFORMATION_REQUEST) {
-                                log_dhcp6_client(client, "Information request ignoring IA PD option");
-
+                                log_dhcp6_client(client, "Ignoring IA PD option in information requesting mode.");
                                 break;
                         }
 
@@ -1243,11 +1230,9 @@ static int client_parse_message(
                         if (r < 0)
                                 return r;
 
-                        if (client->ia_pd.ia_pd.id != iaid_lease) {
-                                log_dhcp6_client(client, "%s has wrong IAID for IA PD",
-                                                 dhcp6_message_type_to_string(message->type));
-                                return -EINVAL;
-                        }
+                        if (client->ia_pd.ia_pd.id != iaid_lease)
+                                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "%s has wrong IAID for IA PD",
+                                                              dhcp6_message_type_to_string(message->type));
 
                         if (lease->pd.addresses) {
                                 lt_t1 = MIN(lt_t1, be32toh(lease->pd.ia_pd.lifetime_t1));
@@ -1309,35 +1294,28 @@ static int client_parse_message(
                 pos += offsetof(DHCP6Option, data) + optlen;
         }
 
-        if (ia_na_status > 0 && ia_pd_status > 0) {
-                log_dhcp6_client(client, "No IA_PD prefix or IA_NA address received. Ignoring.");
-                return -EINVAL;
-        }
+        if (ia_na_status > 0 && ia_pd_status > 0)
+                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "No IA_PD prefix or IA_NA address received. Ignoring.");
 
-        if (!clientid) {
-                log_dhcp6_client(client, "%s has incomplete options",
-                                 dhcp6_message_type_to_string(message->type));
-                return -EINVAL;
-        }
+        if (!clientid)
+                return log_dhcp6_client_errno(client, SYNTHETIC_ERRNO(EINVAL), "%s has incomplete options",
+                                              dhcp6_message_type_to_string(message->type));
 
         if (client->state != DHCP6_STATE_INFORMATION_REQUEST) {
                 r = dhcp6_lease_get_serverid(lease, NULL, NULL);
-                if (r < 0) {
-                        log_dhcp6_client(client, "%s has no server id",
-                                         dhcp6_message_type_to_string(message->type));
-                        return -EINVAL;
-                }
+                if (r < 0)
+                        return log_dhcp6_client_errno(client, r, "%s has no server id",
+                                                      dhcp6_message_type_to_string(message->type));
+        }
 
-        } else {
-                if (lease->ia.addresses) {
-                        lease->ia.ia_na.lifetime_t1 = htobe32(lt_t1);
-                        lease->ia.ia_na.lifetime_t2 = htobe32(lt_t2);
-                }
+        if (lease->ia.addresses) {
+                lease->ia.ia_na.lifetime_t1 = htobe32(lt_t1);
+                lease->ia.ia_na.lifetime_t2 = htobe32(lt_t2);
+        }
 
-                if (lease->pd.addresses) {
-                        lease->pd.ia_pd.lifetime_t1 = htobe32(lt_t1);
-                        lease->pd.ia_pd.lifetime_t2 = htobe32(lt_t2);
-                }
+        if (lease->pd.addresses) {
+                lease->pd.ia_pd.lifetime_t1 = htobe32(lt_t1);
+                lease->pd.ia_pd.lifetime_t2 = htobe32(lt_t2);
         }
 
         client->information_refresh_time_usec = MAX(irt, IRT_MINIMUM);

src/libsystemd/sd-bus/bus-socket.c

@@ -173,12 +173,12 @@ static int bus_socket_auth_verify_client(sd_bus *b) {
         if (!d)
                 return 0;
 
-        e = memmem(d + 2, b->rbuffer_size - (d - (char*) b->rbuffer) - 2, "\r\n", 2);
+        e = memmem_safe(d + 2, b->rbuffer_size - (d - (char*) b->rbuffer) - 2, "\r\n", 2);
         if (!e)
                 return 0;
 
         if (b->accept_fd) {
-                f = memmem(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2);
+                f = memmem_safe(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2);
                 if (!f)
                         return 0;
 
@@ -399,7 +399,7 @@ static int bus_socket_auth_verify_server(sd_bus *b) {
         for (;;) {
                 /* Check if line is complete */
                 line = (char*) b->rbuffer + b->auth_rbegin;
-                e = memmem(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2);
+                e = memmem_safe(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2);
                 if (!e)
                         return processed;
 

src/resolve/resolved-dns-rr.c

@@ -47,8 +47,8 @@ DnsResourceKey* dns_resource_key_new_redirect(const DnsResourceKey *key, const D
         if (cname->key->type == DNS_TYPE_CNAME)
                 return dns_resource_key_new(key->class, key->type, cname->cname.name);
         else {
+                _cleanup_free_ char *destination = NULL;
                 DnsResourceKey *k;
-                char *destination = NULL;
 
                 r = dns_name_change_suffix(dns_resource_key_name(key), dns_resource_key_name(cname->key), cname->dname.name, &destination);
                 if (r < 0)
@@ -58,8 +58,9 @@ DnsResourceKey* dns_resource_key_new_redirect(const DnsResourceKey *key, const D
 
                 k = dns_resource_key_new_consume(key->class, key->type, destination);
                 if (!k)
-                        return mfree(destination);
+                        return NULL;
 
+                TAKE_PTR(destination);
                 return k;
         }
 }