cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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delta-mjpeg-hdr.c (3218B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) STMicroelectronics SA 2013
      4 * Author: Hugues Fruchet <hugues.fruchet@st.com> for STMicroelectronics.
      5 */
      6
      7#include "delta.h"
      8#include "delta-mjpeg.h"
      9
     10#define MJPEG_SOF_0  0xc0
     11#define MJPEG_SOF_1  0xc1
     12#define MJPEG_SOI    0xd8
     13#define MJPEG_MARKER 0xff
     14
     15static char *header_str(struct mjpeg_header *header,
     16			char *str,
     17			unsigned int len)
     18{
     19	char *cur = str;
     20	unsigned int left = len;
     21
     22	if (!header)
     23		return "";
     24
     25	snprintf(cur, left, "[MJPEG header]\n"
     26			"|- length     = %d\n"
     27			"|- precision  = %d\n"
     28			"|- width      = %d\n"
     29			"|- height     = %d\n"
     30			"|- components = %d\n",
     31			header->length,
     32			header->sample_precision,
     33			header->frame_width,
     34			header->frame_height,
     35			header->nb_of_components);
     36
     37	return str;
     38}
     39
     40static int delta_mjpeg_read_sof(struct delta_ctx *pctx,
     41				unsigned char *data, unsigned int size,
     42				struct mjpeg_header *header)
     43{
     44	struct delta_dev *delta = pctx->dev;
     45	unsigned int offset = 0;
     46
     47	if (size < 64)
     48		goto err_no_more;
     49
     50	memset(header, 0, sizeof(*header));
     51	header->length           = be16_to_cpu(*(__be16 *)(data + offset));
     52	offset += sizeof(u16);
     53	header->sample_precision = *(u8 *)(data + offset);
     54	offset += sizeof(u8);
     55	header->frame_height     = be16_to_cpu(*(__be16 *)(data + offset));
     56	offset += sizeof(u16);
     57	header->frame_width      = be16_to_cpu(*(__be16 *)(data + offset));
     58	offset += sizeof(u16);
     59	header->nb_of_components = *(u8 *)(data + offset);
     60	offset += sizeof(u8);
     61
     62	if (header->nb_of_components >= MJPEG_MAX_COMPONENTS) {
     63		dev_err(delta->dev,
     64			"%s   unsupported number of components (%d > %d)\n",
     65			pctx->name, header->nb_of_components,
     66			MJPEG_MAX_COMPONENTS);
     67		return -EINVAL;
     68	}
     69
     70	if ((offset + header->nb_of_components *
     71	     sizeof(header->components[0])) > size)
     72		goto err_no_more;
     73
     74	return 0;
     75
     76err_no_more:
     77	dev_err(delta->dev,
     78		"%s   sof: reached end of %d size input stream\n",
     79		pctx->name, size);
     80	return -ENODATA;
     81}
     82
     83int delta_mjpeg_read_header(struct delta_ctx *pctx,
     84			    unsigned char *data, unsigned int size,
     85			    struct mjpeg_header *header,
     86			    unsigned int *data_offset)
     87{
     88	struct delta_dev *delta = pctx->dev;
     89	unsigned char str[200];
     90
     91	unsigned int ret = 0;
     92	unsigned int offset = 0;
     93	unsigned int soi = 0;
     94
     95	if (size < 2)
     96		goto err_no_more;
     97
     98	offset = 0;
     99	while (1) {
    100		if (data[offset] == MJPEG_MARKER)
    101			switch (data[offset + 1]) {
    102			case MJPEG_SOI:
    103				soi = 1;
    104				*data_offset = offset;
    105				break;
    106
    107			case MJPEG_SOF_0:
    108			case MJPEG_SOF_1:
    109				if (!soi) {
    110					dev_err(delta->dev,
    111						"%s   wrong sequence, got SOF while SOI not seen\n",
    112						pctx->name);
    113					return -EINVAL;
    114				}
    115
    116				ret = delta_mjpeg_read_sof(pctx,
    117							   &data[offset + 2],
    118							   size - (offset + 2),
    119							   header);
    120				if (ret)
    121					goto err;
    122
    123				goto done;
    124
    125			default:
    126				break;
    127			}
    128
    129		offset++;
    130		if ((offset + 2) >= size)
    131			goto err_no_more;
    132	}
    133
    134done:
    135	dev_dbg(delta->dev,
    136		"%s   found header @ offset %d:\n%s", pctx->name,
    137		*data_offset,
    138		header_str(header, str, sizeof(str)));
    139	return 0;
    140
    141err_no_more:
    142	dev_err(delta->dev,
    143		"%s   no header found within %d bytes input stream\n",
    144		pctx->name, size);
    145	return -ENODATA;
    146
    147err:
    148	return ret;
    149}