diff options
| author | Jan Schmidt <thaytan@noraisin.net> | 2009-05-27 17:06:34 +0100 |
|---|---|---|
| committer | Jan Schmidt <thaytan@noraisin.net> | 2009-06-02 13:44:39 +0100 |
| commit | d9544bcc44adcef769cbdf7f6453e140058a3adc (patch) | |
| tree | 8b0c7d3404113a8dfd8817ba9b671fde556512fb | |
| parent | 552793473f3a59a56f31699cb74b114081198413 (diff) | |
pngdec: Avoid possible overflow in calculations
A malformed (or simply huge) PNG file can lead to integer overflow in
calculating the size of the output buffer, leading to crashes or buffer
overflows later. Fixes SA35205 security advisory.
| -rw-r--r-- | ext/libpng/gstpngdec.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/ext/libpng/gstpngdec.c b/ext/libpng/gstpngdec.c index 524b468a6..dde459db7 100644 --- a/ext/libpng/gstpngdec.c +++ b/ext/libpng/gstpngdec.c @@ -201,7 +201,14 @@ user_info_callback (png_structp png_ptr, png_infop info) /* Allocate output buffer */ pngdec->rowbytes = png_get_rowbytes (pngdec->png, pngdec->info); - buffer_size = pngdec->height * GST_ROUND_UP_4 (pngdec->rowbytes); + if (pngdec->rowbytes > (G_MAXUINT32 - 3) + || pngdec->height > G_MAXUINT32 / pngdec->rowbytes) { + ret = GST_FLOW_ERROR; + goto beach; + } + pngdec->rowbytes = GST_ROUND_UP_4 (pngdec->rowbytes); + buffer_size = pngdec->height * pngdec->rowbytes; + ret = gst_pad_alloc_buffer_and_set_caps (pngdec->srcpad, GST_BUFFER_OFFSET_NONE, buffer_size, GST_PAD_CAPS (pngdec->srcpad), &buffer); @@ -228,7 +235,7 @@ user_endrow_callback (png_structp png_ptr, png_bytep new_row, /* If buffer_out doesn't exist, it means buffer_alloc failed, which * will already have set the return code */ if (GST_IS_BUFFER (pngdec->buffer_out)) { - size_t offset = row_num * GST_ROUND_UP_4 (pngdec->rowbytes); + size_t offset = row_num * pngdec->rowbytes; GST_LOG ("got row %u, copying in buffer %p at offset %" G_GSIZE_FORMAT, (guint) row_num, pngdec->buffer_out, offset); @@ -496,7 +503,12 @@ gst_pngdec_task (GstPad * pad) /* Allocate output buffer */ rowbytes = png_get_rowbytes (pngdec->png, pngdec->info); - buffer_size = pngdec->height * GST_ROUND_UP_4 (rowbytes); + if (rowbytes > (G_MAXUINT32 - 3) || pngdec->height > G_MAXUINT32 / rowbytes) { + ret = GST_FLOW_ERROR; + goto pause; + } + rowbytes = GST_ROUND_UP_4 (rowbytes); + buffer_size = pngdec->height * rowbytes; ret = gst_pad_alloc_buffer_and_set_caps (pngdec->srcpad, GST_BUFFER_OFFSET_NONE, buffer_size, GST_PAD_CAPS (pngdec->srcpad), &buffer); @@ -509,7 +521,7 @@ gst_pngdec_task (GstPad * pad) for (i = 0; i < pngdec->height; i++) { rows[i] = inp; - inp += GST_ROUND_UP_4 (rowbytes); + inp += rowbytes; } /* Read the actual picture */ |