avcodec: add FM Screen Capture Codec decoder

[ffmpeg] / libavcodec / pnmdec.c

diff --git a/libavcodec/pnmdec.c b/libavcodec/pnmdec.c
index d4261a4530e386c2ad518069bb323d1543290696..958c5e43b07c05a23f7146937070797dafe9a8fa 100644 (file)
--- a/libavcodec/pnmdec.c
+++ b/libavcodec/pnmdec.c
@@ -43,7 +43,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
     int buf_size         = avpkt->size;
     PNMContext * const s = avctx->priv_data;
     AVFrame * const p    = data;
-    int i, j, n, linesize, h, upgrade = 0, is_mono = 0;
+    int i, j, k, n, linesize, h, upgrade = 0, is_mono = 0;
     unsigned char *ptr;
     int components, sample_len, ret;
 
@@ -124,7 +124,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
     do_read:
         ptr      = p->data[0];
         linesize = p->linesize[0];
-        if (s->bytestream + n * avctx->height > s->bytestream_end)
+        if (n * avctx->height > s->bytestream_end - s->bytestream)
             return AVERROR_INVALIDDATA;
         if(s->type < 4 || (is_mono && s->type==7)){
             for (i=0; i<avctx->height; i++) {
@@ -143,10 +143,14 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
                         v = (*s->bytestream++)&1;
                     } else {
                         /* read a sequence of digits */
-                        do {
+                        for (k = 0; k < 5 && c <= 9; k += 1) {
                             v = 10*v + c;
                             c = (*s->bytestream++) - '0';
-                        } while (c <= 9);
+                        }
+                        if (v > s->maxval) {
+                            av_log(avctx, AV_LOG_ERROR, "value %d larger than maxval %d\n", v, s->maxval);
+                            return AVERROR_INVALIDDATA;
+                        }
                     }
                     if (sample_len == 16) {
                         ((uint16_t*)ptr)[j] = (((1<<sample_len)-1)*v + (s->maxval>>1))/s->maxval;
@@ -188,7 +192,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
             linesize = p->linesize[0];
             if (s->maxval >= 256)
                 n *= 2;
-            if (s->bytestream + n * avctx->height * 3 / 2 > s->bytestream_end)
+            if (n * avctx->height * 3 / 2 > s->bytestream_end - s->bytestream)
                 return AVERROR_INVALIDDATA;
             for (i = 0; i < avctx->height; i++) {
                 samplecpy(ptr, s->bytestream, n, s->maxval);
@@ -218,7 +222,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
             n        = avctx->width * 2;
             ptr      = p->data[0];
             linesize = p->linesize[0];
-            if (s->bytestream + n * avctx->height * 3 / 2 > s->bytestream_end)
+            if (n * avctx->height * 3 / 2 > s->bytestream_end - s->bytestream)
                 return AVERROR_INVALIDDATA;
             for (i = 0; i < avctx->height; i++) {
                 for (j = 0; j < n / 2; j++) {