From 9e573be454b20f2d0b4ab341f9ffa132d1f26ac5 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 16 Dec 2016 13:08:29 +0100
Subject: [PATCH] util-lib: be stricter when decoding hex strings

If a hex string has an uneven length, generate an error instead of
silently assuming a trailing '0' was in place.
---
 src/basic/hexdecoct.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/basic/hexdecoct.c b/src/basic/hexdecoct.c
index c5bda6c4d..6843aedd0 100644
--- a/src/basic/hexdecoct.c
+++ b/src/basic/hexdecoct.c
@@ -97,6 +97,9 @@ int unhexmem(const char *p, size_t l, void **mem, size_t *len) {
         assert(len);
         assert(p);
 
+        if (l % 2 != 0)
+                return -EINVAL;
+
         z = r = malloc((l + 1) / 2 + 1);
         if (!r)
                 return -ENOMEM;
@@ -107,12 +110,10 @@ int unhexmem(const char *p, size_t l, void **mem, size_t *len) {
                 a = unhexchar(x[0]);
                 if (a < 0)
                         return a;
-                else if (x+1 < p + l) {
-                        b = unhexchar(x[1]);
-                        if (b < 0)
-                                return b;
-                } else
-                        b = 0;
+
+                b = unhexchar(x[1]);
+                if (b < 0)
+                        return b;
 
                 *(z++) = (uint8_t) a << 4 | (uint8_t) b;
         }
-- 
2.30.2