[media] coda: drop JPEG buffers not framed by SOI and EOI markers

This patch adds a quick check for valid JPEG frames before feeding them into
the bitstream buffer: Frames that do not begin with the JPEG start of image
marker and end with the end of image marker are dropped.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/platform/coda/coda-bit.c

@@ -231,6 +231,16 @@ void coda_fill_bitstream(struct coda_ctx *ctx)
 
 		src_buf = v4l2_m2m_next_src_buf(ctx->fh.m2m_ctx);
 
+		/* Drop frames that do not start/end with a SOI/EOI markers */
+		if (ctx->codec->src_fourcc == V4L2_PIX_FMT_JPEG &&
+		    !coda_jpeg_check_buffer(ctx, src_buf)) {
+			v4l2_err(&ctx->dev->v4l2_dev,
+				 "dropping invalid JPEG frame\n");
+			src_buf = v4l2_m2m_src_buf_remove(ctx->fh.m2m_ctx);
+			v4l2_m2m_buf_done(src_buf, VB2_BUF_STATE_ERROR);
+			continue;
+		}
+
 		/* Buffer start position */
 		start = ctx->bitstream_fifo.kfifo.in &
 			ctx->bitstream_fifo.kfifo.mask;

drivers/media/platform/coda/coda-jpeg.c

@@ -14,6 +14,9 @@
 
 #include "coda.h"
 
+#define SOI_MARKER	0xffd8
+#define EOI_MARKER	0xffd9
+
 /*
  * Typical Huffman tables for 8-bit precision luminance and
  * chrominance from JPEG ITU-T.81 (ISO/IEC 10918-1) Annex K.3
@@ -174,6 +177,16 @@ int coda_jpeg_write_tables(struct coda_ctx *ctx)
 	return 0;
 }
 
+bool coda_jpeg_check_buffer(struct coda_ctx *ctx, struct vb2_buffer *vb)
+{
+	void *vaddr = vb2_plane_vaddr(vb, 0);
+	u16 soi = be16_to_cpup((__be16 *)vaddr);
+	u16 eoi = be16_to_cpup((__be16 *)(vaddr +
+					  vb2_get_plane_payload(vb, 0) - 2));
+
+	return soi == SOI_MARKER && eoi == EOI_MARKER;
+}
+
 /*
  * Scale quantization table using nonlinear scaling factor
  * u8 qtab[64], scale [50,190]

drivers/media/platform/coda/coda.h

@@ -293,6 +293,7 @@ void coda_bit_stream_end_flag(struct coda_ctx *ctx);
 
 int coda_h264_padding(int size, char *p);
 
+bool coda_jpeg_check_buffer(struct coda_ctx *ctx, struct vb2_buffer *vb);
 int coda_jpeg_write_tables(struct coda_ctx *ctx);
 void coda_set_jpeg_compression_quality(struct coda_ctx *ctx, int quality);