1 files changed, 107 insertions, 56 deletions

diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index a70be14..bb380f6 100644
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -2,20 +2,20 @@
  * 4XM codec
  * Copyright (c) 2003 Michael Niedermayer
  *
- * This file is part of Libav.
+ * This file is part of FFmpeg.
  *
- * Libav is free software; you can redistribute it and/or
+ * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
- * Libav is distributed in the hope that it will be useful,
+ * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
- * License along with Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
@@ -24,6 +24,7 @@
  * 4XM codec.
  */
 
+#include "libavutil/avassert.h"
 #include "libavutil/frame.h"
 #include "libavutil/intreadwrite.h"
 #include "avcodec.h"
@@ -32,6 +33,7 @@
 #include "get_bits.h"
 #include "internal.h"
 
+
 #define BLOCK_TYPE_VLC_BITS 5
 #define ACDC_VLC_BITS 9
 
@@ -129,7 +131,7 @@ typedef struct CFrameBuffer {
 typedef struct FourXContext {
     AVCodecContext *avctx;
     DSPContext dsp;
-    AVFrame *last_picture;
+    AVFrame *current_picture, *last_picture;
     GetBitContext pre_gb;          ///< ac/dc prefix
     GetBitContext gb;
     GetByteContext g;
@@ -283,7 +285,7 @@ static void init_mv(FourXContext *f, int linesize)
     }
 #endif
 
-static inline void mcdc(uint16_t *dst, uint16_t *src, int log2w,
+static inline void mcdc(uint16_t *dst, const uint16_t *src, int log2w,
                         int h, int stride, int scale, unsigned dc)
 {
     int i;
@@ -327,7 +329,7 @@ static inline void mcdc(uint16_t *dst, uint16_t *src, int log2w,
         }
         break;
     default:
-        break;
+        av_assert0(0);
     }
 }
 
@@ -343,11 +345,14 @@ static int decode_p_block(FourXContext *f, uint16_t *dst, uint16_t *src,
     uint16_t *end   = start + stride * (f->avctx->height - h + 1) - (1 << log2w);
     int ret;
 
-    if (code < 0 || code > 6 || log2w < 0)
-        return AVERROR_INVALIDDATA;
+    av_assert0(code >= 0 && code <= 6 && log2w >= 0);
 
     if (code == 0) {
-        src += f->mv[bytestream2_get_byte(&f->g)];
+        if (bytestream2_get_bytes_left(&f->g) < 1) {
+            av_log(f->avctx, AV_LOG_ERROR, "bytestream overread\n");
+            return AVERROR_INVALIDDATA;
+        }
+        src += f->mv[bytestream2_get_byteu(&f->g)];
         if (start > src || src > end) {
             av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n");
             return AVERROR_INVALIDDATA;
@@ -372,21 +377,37 @@ static int decode_p_block(FourXContext *f, uint16_t *dst, uint16_t *src,
     } else if (code == 3 && f->version < 2) {
         mcdc(dst, src, log2w, h, stride, 1, 0);
     } else if (code == 4) {
-        src += f->mv[bytestream2_get_byte(&f->g)];
+        if (bytestream2_get_bytes_left(&f->g) < 1) {
+            av_log(f->avctx, AV_LOG_ERROR, "bytestream overread\n");
+            return AVERROR_INVALIDDATA;
+        }
+        src += f->mv[bytestream2_get_byteu(&f->g)];
         if (start > src || src > end) {
             av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n");
             return AVERROR_INVALIDDATA;
         }
-        mcdc(dst, src, log2w, h, stride, 1, bytestream2_get_le16(&f->g2));
+        if (bytestream2_get_bytes_left(&f->g2) < 2){
+            av_log(f->avctx, AV_LOG_ERROR, "wordstream overread\n");
+            return AVERROR_INVALIDDATA;
+        }
+        mcdc(dst, src, log2w, h, stride, 1, bytestream2_get_le16u(&f->g2));
     } else if (code == 5) {
-        mcdc(dst, src, log2w, h, stride, 0, bytestream2_get_le16(&f->g2));
+        if (bytestream2_get_bytes_left(&f->g2) < 2) {
+            av_log(f->avctx, AV_LOG_ERROR, "wordstream overread\n");
+            return AVERROR_INVALIDDATA;
+        }
+        mcdc(dst, src, log2w, h, stride, 0, bytestream2_get_le16u(&f->g2));
     } else if (code == 6) {
+        if (bytestream2_get_bytes_left(&f->g2) < 4) {
+            av_log(f->avctx, AV_LOG_ERROR, "wordstream overread\n");
+            return AVERROR_INVALIDDATA;
+        }
         if (log2w) {
-            dst[0]      = bytestream2_get_le16(&f->g2);
-            dst[1]      = bytestream2_get_le16(&f->g2);
+            dst[0]      = bytestream2_get_le16u(&f->g2);
+            dst[1]      = bytestream2_get_le16u(&f->g2);
         } else {
-            dst[0]      = bytestream2_get_le16(&f->g2);
-            dst[stride] = bytestream2_get_le16(&f->g2);
+            dst[0]      = bytestream2_get_le16u(&f->g2);
+            dst[stride] = bytestream2_get_le16u(&f->g2);
         }
     }
     return 0;
@@ -408,19 +429,18 @@ static int decode_p_frame(FourXContext *f, AVFrame *frame,
     if (!f->last_picture->data[0]) {
         if ((ret = ff_get_buffer(f->avctx, f->last_picture,
                                  AV_GET_BUFFER_FLAG_REF)) < 0) {
-            av_log(f->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
             return ret;
         }
-        memset(f->last_picture->data[0], 0,
-               f->avctx->height * FFABS(f->last_picture->linesize[0]));
+        for (y=0; y<f->avctx->height; y++)
+            memset(f->last_picture->data[0] + y*f->last_picture->linesize[0], 0, 2*f->avctx->width);
     }
 
     src = (uint16_t *)f->last_picture->data[0];
 
     if (f->version > 1) {
-        if (length < 20)
-            return AVERROR_INVALIDDATA;
         extra           = 20;
+        if (length < extra)
+            return AVERROR_INVALIDDATA;
         bitstream_size  = AV_RL32(buf + 8);
         wordstream_size = AV_RL32(buf + 12);
         bytestream_size = AV_RL32(buf + 16);
@@ -431,13 +451,12 @@ static int decode_p_frame(FourXContext *f, AVFrame *frame,
         bytestream_size = FFMAX(length - bitstream_size - wordstream_size, 0);
     }
 
-    if (bitstream_size + bytestream_size + wordstream_size + extra != length
-        || bitstream_size  > (1 << 26)
-        || bytestream_size > (1 << 26)
-        || wordstream_size > (1 << 26)) {
-        av_log(f->avctx, AV_LOG_ERROR, "lengths %d %d %d %d\n",
-               bitstream_size, bytestream_size, wordstream_size,
-               bitstream_size + bytestream_size + wordstream_size - length);
+    if (bitstream_size > length || bitstream_size >= INT_MAX/8 ||
+        bytestream_size > length - bitstream_size ||
+        wordstream_size > length - bytestream_size - bitstream_size ||
+        extra > length - bytestream_size - bitstream_size - wordstream_size) {
+        av_log(f->avctx, AV_LOG_ERROR, "lengths %d %d %d %d\n", bitstream_size, bytestream_size, wordstream_size,
+        bitstream_size+ bytestream_size+ wordstream_size - length);
         return AVERROR_INVALIDDATA;
     }
 
@@ -479,6 +498,11 @@ static int decode_i_block(FourXContext *f, int16_t *block)
 {
     int code, i, j, level, val;
 
+    if (get_bits_left(&f->gb) < 2){
+        av_log(f->avctx, AV_LOG_ERROR, "%d bits left before decode_i_block()\n", get_bits_left(&f->gb));
+        return -1;
+    }
+
     /* DC coef */
     val = get_vlc2(&f->pre_gb, f->pre_vlc.table, ACDC_VLC_BITS, 3);
     if (val >> 4)
@@ -580,7 +604,7 @@ static int decode_i_mb(FourXContext *f)
 
 static const uint8_t *read_huffman_tables(FourXContext *f,
                                           const uint8_t * const buf,
-                                          int len)
+                                          int buf_size)
 {
     int frequency[512] = { 0 };
     uint8_t flag[512];
@@ -589,6 +613,7 @@ static const uint8_t *read_huffman_tables(FourXContext *f,
     int bits_tab[257];
     int start, end;
     const uint8_t *ptr = buf;
+    const uint8_t *ptr_end = buf + buf_size;
     int j;
 
     memset(up, -1, sizeof(up));
@@ -598,10 +623,10 @@ static const uint8_t *read_huffman_tables(FourXContext *f,
     for (;;) {
         int i;
 
-        len -= end - start + 1;
-
-        if (end < start || len < 0)
+        if (ptr_end - ptr < FFMAX(end - start + 1, 0) + 1) {
+            av_log(f->avctx, AV_LOG_ERROR, "invalid data in read_huffman_tables\n");
             return NULL;
+        }
 
         for (i = start; i <= end; i++)
             frequency[i] = *ptr++;
@@ -609,9 +634,6 @@ static const uint8_t *read_huffman_tables(FourXContext *f,
         if (start == 0)
             break;
 
-        if (--len < 0)
-            return NULL;
-
         end = *ptr++;
     }
     frequency[256] = 1;
@@ -619,6 +641,11 @@ static const uint8_t *read_huffman_tables(FourXContext *f,
     while ((ptr - buf) & 3)
         ptr++; // 4byte align
 
+    if (ptr > ptr_end) {
+        av_log(f->avctx, AV_LOG_ERROR, "ptr overflow in read_huffman_tables\n");
+        return NULL;
+    }
+
     for (j = 257; j < 512; j++) {
         int min_freq[2] = { 256 * 256, 256 * 256 };
         int smallest[2] = { 0, 0 };
@@ -688,6 +715,7 @@ static int decode_i2_frame(FourXContext *f, AVFrame *frame, const uint8_t *buf,
     const int mbs    = (FFALIGN(width, 16) >> 4) * (FFALIGN(height, 16) >> 4);
     uint16_t *dst    = (uint16_t*)frame->data[0];
     const int stride =            frame->linesize[0]>>1;
+    const uint8_t *buf_end = buf + length;
     GetByteContext g3;
 
     if (length < mbs * 8) {
@@ -699,6 +727,8 @@ static int decode_i2_frame(FourXContext *f, AVFrame *frame, const uint8_t *buf,
     for (y = 0; y < height; y += 16) {
         for (x = 0; x < width; x += 16) {
             unsigned int color[4] = { 0 }, bits;
+            if (buf_end - buf < 8)
+                return -1;
             // warning following is purely guessed ...
             color[0] = bytestream2_get_le16u(&g3);
             color[1] = bytestream2_get_le16u(&g3);
@@ -732,16 +762,14 @@ static int decode_i_frame(FourXContext *f, AVFrame *frame, const uint8_t *buf, i
     const int width  = f->avctx->width;
     const int height = f->avctx->height;
     const unsigned int bitstream_size = AV_RL32(buf);
-    int token_count av_unused;
     unsigned int prestream_size;
     const uint8_t *prestream;
 
-    if (length < bitstream_size + 12) {
+    if (bitstream_size > (1<<26) || length < bitstream_size + 12) {
         av_log(f->avctx, AV_LOG_ERROR, "packet size too small\n");
         return AVERROR_INVALIDDATA;
     }
 
-    token_count    =     AV_RL32(buf + bitstream_size + 8);
     prestream_size = 4 * AV_RL32(buf + bitstream_size + 4);
     prestream      =             buf + bitstream_size + 12;
 
@@ -759,6 +787,8 @@ static int decode_i_frame(FourXContext *f, AVFrame *frame, const uint8_t *buf, i
         return AVERROR_INVALIDDATA;
     }
 
+    av_assert0(prestream <= buf + length);
+
     init_get_bits(&f->gb, buf + 4, 8 * bitstream_size);
 
     prestream_size = length + buf - prestream;
@@ -816,12 +846,19 @@ static int decode_frame(AVCodecContext *avctx, void *data,
         const int data_size  = buf_size - 20;
         CFrameBuffer *cfrm;
 
-        if (data_size < 0)
+        if (f->version <= 1) {
+            av_log(f->avctx, AV_LOG_ERROR, "cfrm in version %d\n", f->version);
             return AVERROR_INVALIDDATA;
+        }
 
         id         = AV_RL32(buf + 12);
         whole_size = AV_RL32(buf + 16);
 
+        if (data_size < 0 || whole_size < 0) {
+            av_log(f->avctx, AV_LOG_ERROR, "sizes invalid\n");
+            return AVERROR_INVALIDDATA;
+        }
+
         for (i = 0; i < CFRAME_BUFFER_COUNT; i++)
             if (f->cfrm[i].id && f->cfrm[i].id < avctx->frame_number)
                 av_log(f->avctx, AV_LOG_ERROR, "lost c frame %d\n",
@@ -840,11 +877,14 @@ static int decode_frame(AVCodecContext *avctx, void *data,
         }
         cfrm = &f->cfrm[i];
 
+        if (data_size > UINT_MAX -  cfrm->size - FF_INPUT_BUFFER_PADDING_SIZE)
+            return AVERROR_INVALIDDATA;
+
         cfrm->data = av_fast_realloc(cfrm->data, &cfrm->allocated_size,
                                      cfrm->size + data_size + FF_INPUT_BUFFER_PADDING_SIZE);
         // explicit check needed as memcpy below might not catch a NULL
         if (!cfrm->data) {
-            av_log(f->avctx, AV_LOG_ERROR, "realloc failure");
+            av_log(f->avctx, AV_LOG_ERROR, "realloc failure\n");
             return AVERROR(ENOMEM);
         }
 
@@ -871,26 +911,32 @@ static int decode_frame(AVCodecContext *avctx, void *data,
         frame_size = buf_size - 12;
     }
 
+    FFSWAP(AVFrame*, f->current_picture, f->last_picture);
+
     // alternatively we would have to use our own buffer management
     avctx->flags |= CODEC_FLAG_EMU_EDGE;
 
-    if ((ret = ff_get_buffer(avctx, picture, AV_GET_BUFFER_FLAG_REF)) < 0) {
-        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+    if ((ret = ff_reget_buffer(avctx, f->current_picture)) < 0)
         return ret;
-    }
 
     if (frame_4cc == AV_RL32("ifr2")) {
-        picture->pict_type = AV_PICTURE_TYPE_I;
-        if ((ret = decode_i2_frame(f, picture, buf - 4, frame_size + 4)) < 0)
+        f->current_picture->pict_type = AV_PICTURE_TYPE_I;
+        if ((ret = decode_i2_frame(f, f->current_picture, buf - 4, frame_size + 4)) < 0) {
+            av_log(f->avctx, AV_LOG_ERROR, "decode i2 frame failed\n");
             return ret;
+        }
     } else if (frame_4cc == AV_RL32("ifrm")) {
-        picture->pict_type = AV_PICTURE_TYPE_I;
-        if ((ret = decode_i_frame(f, picture, buf, frame_size)) < 0)
+        f->current_picture->pict_type = AV_PICTURE_TYPE_I;
+        if ((ret = decode_i_frame(f, f->current_picture, buf, frame_size)) < 0) {
+            av_log(f->avctx, AV_LOG_ERROR, "decode i frame failed\n");
             return ret;
+        }
     } else if (frame_4cc == AV_RL32("pfrm") || frame_4cc == AV_RL32("pfr2")) {
-        picture->pict_type = AV_PICTURE_TYPE_P;
-        if ((ret = decode_p_frame(f, picture, buf, frame_size)) < 0)
+        f->current_picture->pict_type = AV_PICTURE_TYPE_P;
+        if ((ret = decode_p_frame(f, f->current_picture, buf, frame_size)) < 0) {
+            av_log(f->avctx, AV_LOG_ERROR, "decode p frame failed\n");
             return ret;
+        }
     } else if (frame_4cc == AV_RL32("snd_")) {
         av_log(avctx, AV_LOG_ERROR, "ignoring snd_ chunk length:%d\n",
                buf_size);
@@ -899,10 +945,9 @@ static int decode_frame(AVCodecContext *avctx, void *data,
                buf_size);
     }
 
-    picture->key_frame = picture->pict_type == AV_PICTURE_TYPE_I;
+    f->current_picture->key_frame = f->current_picture->pict_type == AV_PICTURE_TYPE_I;
 
-    av_frame_unref(f->last_picture);
-    if ((ret = av_frame_ref(f->last_picture, picture)) < 0)
+    if ((ret = av_frame_ref(picture, f->current_picture)) < 0)
         return ret;
     *got_frame = 1;
 
@@ -917,7 +962,11 @@ static av_cold int decode_init(AVCodecContext *avctx)
 
     if (avctx->extradata_size != 4 || !avctx->extradata) {
         av_log(avctx, AV_LOG_ERROR, "extradata wrong or missing\n");
-        return 1;
+        return AVERROR_INVALIDDATA;
+    }
+    if((avctx->width % 16) || (avctx->height % 16)) {
+        av_log(avctx, AV_LOG_ERROR, "unsupported width/height\n");
+        return AVERROR_INVALIDDATA;
     }
 
     f->version = AV_RL32(avctx->extradata) >> 16;
@@ -930,8 +979,9 @@ static av_cold int decode_init(AVCodecContext *avctx)
     else
         avctx->pix_fmt = AV_PIX_FMT_BGR555;
 
-    f->last_picture = av_frame_alloc();
-    if (!f->last_picture)
+    f->current_picture = av_frame_alloc();
+    f->last_picture    = av_frame_alloc();
+    if (!f->current_picture  || !f->last_picture)
         return AVERROR(ENOMEM);
 
     return 0;
@@ -950,6 +1000,7 @@ static av_cold int decode_end(AVCodecContext *avctx)
         f->cfrm[i].allocated_size = 0;
     }
     ff_free_vlc(&f->pre_vlc);
+    av_frame_free(&f->current_picture);
     av_frame_free(&f->last_picture);
 
     return 0;