On Thu, May 11, 2017 at 09:01:57AM +0200, Paul B Mahol wrote: > On 5/11/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: > > Most of these were found through code review in response to > > fixing 1466/clusterfuzz-testcase-minimized-5961584419536896 > > There is thus no testcase for most of this. > > The initial issue was Found-by: continuous fuzzing process > > https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg > > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > --- > > libavcodec/xpmdec.c | 37 ++++++++++++++++++++++++++++++------- > > 1 file changed, 30 insertions(+), 7 deletions(-) > > > > diff --git a/libavcodec/xpmdec.c b/libavcodec/xpmdec.c > > index 9112d4cb5e..03172e4aad 100644 > > --- a/libavcodec/xpmdec.c > > +++ b/libavcodec/xpmdec.c > > @@ -29,6 +29,8 @@ > > typedef struct XPMContext { > > uint32_t *pixels; > > int pixels_size; > > + uint8_t *buf; > > + int buf_size; > > } XPMDecContext; > > > > typedef struct ColorEntry { > > @@ -233,6 +235,8 @@ static uint32_t color_string_to_rgba(const char *p, int > > len) > > const ColorEntry *entry; > > char color_name[100]; > > > > + len = FFMIN(FFMAX(len, 0), sizeof(color_name) - 1); > > + > > if (*p == '#') { > > p++; > > len--; > > @@ -299,18 +303,25 @@ static int xpm_decode_frame(AVCodecContext *avctx, > > void *data, > > { > > XPMDecContext *x = avctx->priv_data; > > AVFrame *p=data; > > - const uint8_t *end, *ptr = avpkt->data; > > + const uint8_t *end, *ptr; > > int ncolors, cpp, ret, i, j; > > int64_t size; > > uint32_t *dst; > > > > avctx->pix_fmt = AV_PIX_FMT_BGRA; > > > > - end = avpkt->data + avpkt->size; > > - while (memcmp(ptr, "/* XPM */", 9) && ptr < end - 9) > > + av_fast_padded_malloc(&x->buf, &x->buf_size, avpkt->size); > > + if (!x->buf) > > + return AVERROR(ENOMEM); > > + memcpy(x->buf, avpkt->data, avpkt->size); > > + x->buf[avpkt->size] = 0; > > + > > + ptr = x->buf; > > + end = x->buf + avpkt->size; > > + while (end - ptr > 9 && memcmp(ptr, "/* XPM */", 9)) > > ptr++; > > > > - if (ptr >= end) { > > + if (end - ptr <= 9) { > > av_log(avctx, AV_LOG_ERROR, "missing signature\n"); > > return AVERROR_INVALIDDATA; > > } > > @@ -335,7 +346,7 @@ static int xpm_decode_frame(AVCodecContext *avctx, void > > *data, > > > > size = 1; > > for (i = 0; i < cpp; i++) > > - size *= 94; > > + size *= 95; > > > > if (ncolors <= 0 || ncolors > size) { > > av_log(avctx, AV_LOG_ERROR, "invalid number of colors: %d\n", > > ncolors); > > @@ -349,12 +360,15 @@ static int xpm_decode_frame(AVCodecContext *avctx, > > void *data, > > return AVERROR(ENOMEM); > > > > ptr += mod_strcspn(ptr, ",") + 1; > > + if (end - ptr < 1) > > + return AVERROR_INVALIDDATA; > > + > > for (i = 0; i < ncolors; i++) { > > const uint8_t *index; > > int len; > > > > ptr += mod_strcspn(ptr, "\"") + 1; > > - if (ptr + cpp > end) > > + if (end - ptr < cpp) > > return AVERROR_INVALIDDATA; > > index = ptr; > > ptr += cpp; > > @@ -373,14 +387,20 @@ static int xpm_decode_frame(AVCodecContext *avctx, > > void *data, > > > > x->pixels[ret] = color_string_to_rgba(ptr, len); > > ptr += mod_strcspn(ptr, ",") + 1; > > + if (end - ptr < 1) > > + return AVERROR_INVALIDDATA; > > } > > > > for (i = 0; i < avctx->height; i++) { > > dst = (uint32_t *)(p->data[0] + i * p->linesize[0]); > > + if (end - ptr < 1) > > + return AVERROR_INVALIDDATA; > > ptr += mod_strcspn(ptr, "\"") + 1; > > + if (end - ptr < 1) > > + return AVERROR_INVALIDDATA; > > > > for (j = 0; j < avctx->width; j++) { > > - if (ptr + cpp > end) > > + if (end - ptr < cpp) > > return AVERROR_INVALIDDATA; > > > > if ((ret = ascii2index(ptr, cpp)) < 0) > > @@ -405,6 +425,9 @@ static av_cold int xpm_decode_close(AVCodecContext > > *avctx) > > XPMDecContext *x = avctx->priv_data; > > av_freep(&x->pixels); > > > > + av_freep(&x->buf); > > + x->buf_size = 0; > > + > > return 0; > > } > > > > -- > > 2.11.0 > > > > _______________________________________________ > > ffmpeg-devel mailing list > > ffmpeg-devel@ffmpeg.org > > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > > > This is suboptimal solution.
That comment isnt helpfull in improving the patch. It doesnt say what it is that you would like changed. I could probably replace string functions and avoid copying the whole packet if thats what you suggest ? it makes this bugfix more complex though [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Frequently ignored answer#1 FFmpeg bugs should be sent to our bugtracker. User questions about the command line tools should be sent to the ffmpeg-user ML. And questions about how to use libav* should be sent to the libav-user ML.
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