ape demuxer: check for EOF in potentially long loops

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
(cherry-picked from commit 488b2984fe)
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

libavformat/ape.c

@@ -276,7 +276,9 @@ static int ape_read_header(AVFormatContext * s)
         ape->seektable = av_malloc(ape->seektablelength);
         if (!ape->seektable)
             return AVERROR(ENOMEM);
-        for (i = 0; i < ape->seektablelength / sizeof(uint32_t); i++)
+        for (i = 0;
+             i < ape->seektablelength / sizeof(uint32_t) && !pb->eof_reached;
+             i++)
             ape->seektable[i] = avio_rl32(pb);
     }