From e37ca0090343e0dae97e967d467bab56d502c37a Mon Sep 17 00:00:00 2001
From: Nikias Bassen
Date: Sat, 18 Feb 2017 18:09:34 +0100
Subject: base64: Prevent undefined shift when parsing invalid base64 encoded
 data

Credit to OSS-Fuzz
---
 src/base64.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/base64.c b/src/base64.c
index ba8acca..ee02356 100644
--- a/src/base64.c
+++ b/src/base64.c
@@ -101,13 +101,13 @@ unsigned char *base64decode(const char *buf, size_t *size)
 			w3 = tmpval[2];
 			w4 = tmpval[3];
 
-			if (w2 >= 0) {
+			if (w1 >= 0 && w2 >= 0) {
 				outbuf[p++] = (unsigned char)(((w1 << 2) + (w2 >> 4)) & 0xFF);
 			}
-			if (w3 >= 0) {
+			if (w2 >= 0 && w3 >= 0) {
 				outbuf[p++] = (unsigned char)(((w2 << 4) + (w3 >> 2)) & 0xFF);
 			}
-			if (w4 >= 0) {
+			if (w3 >= 0 && w4 >= 0) {
 				outbuf[p++] = (unsigned char)(((w3 << 6) + w4) & 0xFF);
 			}
 		}
-- 
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