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authorJan Schmidt <thaytan@noraisin.net>2009-05-27 17:06:34 +0100
committerJan Schmidt <thaytan@noraisin.net>2009-06-02 13:44:39 +0100
commitd9544bcc44adcef769cbdf7f6453e140058a3adc (patch)
tree8b0c7d3404113a8dfd8817ba9b671fde556512fb
parent552793473f3a59a56f31699cb74b114081198413 (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.c20
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 */