On Thu, 20 Mar 2014, wm4 wrote:

From: Michael Niedermayer <michae...@gmx.at>

This avoids the 2nd buffer and fixes the palette truncated check

Signed-off-by: Michael Niedermayer <michae...@gmx.at>
---
I guess the length check is off by 1, so this defensive measure was
ineffective, even if it wasn't a real bug.
---
libavformat/isom.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/libavformat/isom.c b/libavformat/isom.c
index e15875e..3f420e7 100644
--- a/libavformat/isom.c
+++ b/libavformat/isom.c
@@ -26,6 +26,7 @@
#include "isom.h"
#include "libavcodec/mpeg4audio.h"
#include "libavcodec/mpegaudiodata.h"
+#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"

/* http://www.mp4ra.org */
@@ -438,28 +439,25 @@ static uint32_t yuv_to_rgba(uint32_t ycbcr)

static int mov_rewrite_dvd_sub_extradata(AVStream *st)
{
-    char pal_s[256];
-    char buf[256];
-    int pal_s_pos = 0;
+    char buf[256] = {0};
    uint8_t *src = st->codec->extradata;
    int i;

    if (st->codec->extradata_size != 64)
        return 0;

+    snprintf(buf, sizeof(buf), "size: %dx%d\npalette: ",
+             st->codec->width, st->codec->height);
+
    for (i = 0; i < 16; i++) {
        uint32_t yuv = AV_RB32(src + i * 4);
        uint32_t rgba = yuv_to_rgba(yuv);

-        snprintf(pal_s + pal_s_pos, sizeof(pal_s) - pal_s_pos, "%06x%s", rgba,
-                 i != 15 ? ", " : "");
-        pal_s_pos = strlen(pal_s);
-        if (pal_s_pos >= sizeof(pal_s))
-            return 0;
+        av_strlcatf(buf, sizeof(buf), "%06x%s", rgba, i != 15 ? ", " : "");
    }

-    snprintf(buf, sizeof(buf), "size: %dx%d\npalette: %s\n",
-             st->codec->width, st->codec->height, pal_s);
+    if (av_strlcat(buf, "\n", sizeof(buf)) >= sizeof(buf))
+        return 0;

    av_freep(&st->codec->extradata);
    st->codec->extradata_size = 0;
--
1.9.0

Ok

// Martin
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