[FFmpeg-cvslog] libavutil/base64: Try not to write over the array end

[Michael Niedermayer]

ffmpeg | branch: release/5.1 | Michael Niedermayer <michael at niedermayer.cc> | Sat May 11 03:13:17 2024 +0200| [f7fcdeb6a0e9a1aa0d3ed2eacc503404c8409cb8] | committer: Michael Niedermayer

libavutil/base64: Try not to write over the array end

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 2d216566f258badd07bc58de1e089b6e4175dc46)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f7fcdeb6a0e9a1aa0d3ed2eacc503404c8409cb8
---

 libavutil/base64.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavutil/base64.c b/libavutil/base64.c
index 3e66f4fcbe..69e11e6f5e 100644
--- a/libavutil/base64.c
+++ b/libavutil/base64.c
@@ -127,10 +127,12 @@ validity_check:
     }
 
 out3:
-    *dst++ = v >> 10;
+    if (end - dst)
+        *dst++ = v >> 10;
     v <<= 2;
 out2:
-    *dst++ = v >> 4;
+    if (end - dst)
+        *dst++ = v >> 4;
 out1:
 out0:
     return bits & 1 ? AVERROR_INVALIDDATA : out ? dst - out : 0;