tree-wide: check results of PAGE_ALIGN()

Fixes CID#1491282, CID#1491283, CID#1491285, CID#1491288.

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

@@ -27,8 +27,11 @@
 #include "memory-util.h"
 
 void close_and_munmap(int fd, void *address, size_t size) {
-        if (size > 0)
-                assert_se(munmap(address, PAGE_ALIGN(size)) >= 0);
+        if (size > 0) {
+                size = PAGE_ALIGN(size);
+                assert(size < SIZE_MAX);
+                assert_se(munmap(address, size) >= 0);
+        }
 
         safe_close(fd);
 }

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

@@ -2490,6 +2490,8 @@ int bus_body_part_map(struct bus_body_part *part) {
 
         shift = PAGE_OFFSET(part->memfd_offset);
         psz = PAGE_ALIGN(part->size + shift);
+        if (psz >= SIZE_MAX)
+                return -EFBIG;
 
         if (part->memfd >= 0)
                 p = mmap(NULL, psz, PROT_READ, MAP_PRIVATE, part->memfd, part->memfd_offset - shift);

src/libsystemd/sd-journal/journal-authenticate.c

@@ -379,7 +379,9 @@ int journal_file_fss_load(JournalFile *f) {
         if (le64toh(header->start_usec) <= 0 || le64toh(header->interval_usec) <= 0)
                 return -EBADMSG;
 
-        f->fss_file = mmap(NULL, PAGE_ALIGN(f->fss_file_size), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+        size_t sz = PAGE_ALIGN(f->fss_file_size);
+        assert(sz < SIZE_MAX);
+        f->fss_file = mmap(NULL, sz, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
         if (f->fss_file == MAP_FAILED) {
                 f->fss_file = NULL;
                 return -errno;

src/libsystemd/sd-journal/journal-file.c

@@ -302,9 +302,11 @@ JournalFile* journal_file_close(JournalFile *f) {
 #endif
 
 #if HAVE_GCRYPT
-        if (f->fss_file)
-                munmap(f->fss_file, PAGE_ALIGN(f->fss_file_size));
-        else
+        if (f->fss_file) {
+                size_t sz = PAGE_ALIGN(f->fss_file_size);
+                assert(sz < SIZE_MAX);
+                munmap(f->fss_file, sz);
+        } else
                 free(f->fsprg_state);
 
         free(f->fsprg_seed);