From 4339aa85279d268a671a656f142445559be771b7 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Wed, 14 Nov 2018 18:39:37 +0100

Subject: [PATCH] format-table: make sure we never call memcmp() with NULL

 parameters

(cherry picked from commit 88db94fa57c9a5b1a0b926c49d3624fc84c88090)

Related: #1689832

---

 src/basic/format-table.c | 2 +-

 src/basic/util.h         | 9 +++++++++

 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/basic/format-table.c b/src/basic/format-table.c

index 0a1777e9a2..5517adad82 100644

--- a/src/basic/format-table.c

+++ b/src/basic/format-table.c

@@ -291,7 +291,7 @@ static bool table_data_matches(

         if (k != l)

                 return false;

-        return memcmp(data, d->data, l) == 0;

+        return memcmp_safe(data, d->data, l) == 0;

 }

 static TableData *table_data_new(

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

index 27b5a09782..b68ef25ed8 100644

--- a/src/basic/util.h

+++ b/src/basic/util.h

@@ -123,6 +123,15 @@ static inline void memcpy_safe(void *dst, const void *src, size_t n) {

         memcpy(dst, src, n);

 }

+/* Normal memcmp requires s1 and s2 to be nonnull. We do nothing if n is 0. */

+static inline int memcmp_safe(const void *s1, const void *s2, size_t n) {

+        if (n == 0)

+                return 0;

+        assert(s1);

+        assert(s2);

+        return memcmp(s1, s2, n);

+}

+

 int on_ac_power(void);

 #define memzero(x,l) (memset((x), 0, (l)))