From fc6e036599be0ff41b9312086a7a20c25025ebeb Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Dec 15 2020 09:45:35 +0000
Subject: tree-wide: various ubsan zero size memory fixes


Fixes: #10346
(cherry picked from commit 65f95765d05ddcd9e5849b68c379afa7e87d1248)

Resolves: #1683319

patch_name: 0180-tree-wide-various-ubsan-zero-size-memory-fixes.patch
present_in_specfile: true
location_in_specfile: 180
squash_commits: true

---

diff --git a/src/basic/bitmap.c b/src/basic/bitmap.c
index c17c6a7..a4cd645 100644
--- a/src/basic/bitmap.c
+++ b/src/basic/bitmap.c
@@ -206,7 +206,7 @@ bool bitmap_equal(Bitmap *a, Bitmap *b) {
                 return true;
 
         common_n_bitmaps = MIN(a->n_bitmaps, b->n_bitmaps);
-        if (memcmp(a->bitmaps, b->bitmaps, sizeof(uint64_t) * common_n_bitmaps) != 0)
+        if (memcmp_safe(a->bitmaps, b->bitmaps, sizeof(uint64_t) * common_n_bitmaps) != 0)
                 return false;
 
         c = a->n_bitmaps > b->n_bitmaps ? a : b;
diff --git a/src/basic/util.h b/src/basic/util.h
index b68ef25..4659a21 100644
--- a/src/basic/util.h
+++ b/src/basic/util.h
@@ -134,7 +134,13 @@ static inline int memcmp_safe(const void *s1, const void *s2, size_t n) {
 
 int on_ac_power(void);
 
-#define memzero(x,l) (memset((x), 0, (l)))
+#define memzero(x,l)                                            \
+        ({                                                      \
+                size_t _l_ = (l);                               \
+                void *_x_ = (x);                                \
+                _l_ == 0 ? _x_ : memset(_x_, 0, _l_);           \
+        })
+
 #define zero(x) (memzero(&(x), sizeof(x)))
 
 static inline void *mempset(void *s, int c, size_t n) {
diff --git a/src/test/test-hexdecoct.c b/src/test/test-hexdecoct.c
index da9f300..a972ddc 100644
--- a/src/test/test-hexdecoct.c
+++ b/src/test/test-hexdecoct.c
@@ -84,7 +84,7 @@ static void test_unhexmem_one(const char *s, size_t l, int retval) {
                         l = strlen(s);
 
                 assert_se(hex = hexmem(mem, len));
-                answer = strndupa(s, l);
+                answer = strndupa(s ?: "", l);
                 assert_se(streq(delete_chars(answer, WHITESPACE), hex));
         }
 }