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mkv - truncate the element size instead of failing #867

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mkv - truncate the element size instead of failing #867

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30 changes: 19 additions & 11 deletions vod/mkv/ebml.c
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Original file line number Diff line number Diff line change
Expand Up @@ -97,9 +97,10 @@ ebml_read_num(ebml_context_t* context, uint64_t* result, size_t max_size, int re
}

static vod_status_t
ebml_read_size(ebml_context_t* context, uint64_t* result)
ebml_read_size(ebml_context_t* context, bool_t truncate, uint64_t* result)
{
vod_status_t rc;
uint64_t size_left;

rc = ebml_read_num(context, result, 8, 1);
if (rc < 0)
Expand All @@ -109,16 +110,22 @@ ebml_read_size(ebml_context_t* context, uint64_t* result)
return rc;
}

size_left = context->end_pos - context->cur_pos;
if (is_unknown_size(*result, rc))
{
*result = context->end_pos - context->cur_pos;
*result = size_left;
}
else if (*result > (uint64_t)(context->end_pos - context->cur_pos))
else if (*result > size_left)
{
vod_log_error(VOD_LOG_ERR, context->request_context->log, 0,
"ebml_read_size: size %uL greater than the remaining stream bytes %uL",
*result, (uint64_t)(context->end_pos - context->cur_pos));
return VOD_BAD_DATA;
if (!truncate)
{
vod_log_error(VOD_LOG_ERR, context->request_context->log, 0,
"ebml_read_size: size %uL greater than the remaining stream bytes %uL",
*result, size_left);
return VOD_BAD_DATA;
}

*result = size_left;
}

return VOD_OK;
Expand Down Expand Up @@ -192,25 +199,26 @@ ebml_parse_element(ebml_context_t* context, ebml_spec_t* spec, void* dest)
ebml_context_t next_context;
uint64_t max_size;
uint64_t size;
uint32_t type = spec->type & EBML_TYPE_MASK;
void* cur_dest;
vod_status_t rc;

// size
rc = ebml_read_size(context, &size);
rc = ebml_read_size(context, spec->type & EBML_TRUNCATE, &size);
if (rc != VOD_OK)
{
vod_log_debug1(VOD_LOG_DEBUG_LEVEL, context->request_context->log, 0,
"ebml_parse_element: ebml_read_size failed, id=0x%uxD", spec->id);
return rc;
}

if (spec->type == EBML_NONE)
if (type == EBML_NONE)
{
context->cur_pos += size;
return VOD_OK;
}

max_size = ebml_max_sizes[spec->type];
max_size = ebml_max_sizes[type];
if (max_size && size > max_size)
{
vod_log_error(VOD_LOG_ERR, context->request_context->log, 0,
Expand All @@ -220,7 +228,7 @@ ebml_parse_element(ebml_context_t* context, ebml_spec_t* spec, void* dest)

cur_dest = (u_char*)dest + spec->offset;

switch (spec->type)
switch (type)
{
case EBML_UINT:
rc = ebml_read_uint(context, size, cur_dest);
Expand Down
5 changes: 4 additions & 1 deletion vod/mkv/ebml.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,9 @@ typedef enum {
EBML_BINARY,
EBML_MASTER,
EBML_CUSTOM,

EBML_TYPE_MASK = 0x00ffffff,
EBML_TRUNCATE = 0x01000000,
} ebml_type_t;

typedef struct {
Expand All @@ -26,7 +29,7 @@ typedef struct {

typedef struct {
uint32_t id;
ebml_type_t type;
uint32_t type;
off_t offset;
void* child;
} ebml_spec_t;
Expand Down
8 changes: 4 additions & 4 deletions vod/mkv/mkv_format.c
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Original file line number Diff line number Diff line change
Expand Up @@ -144,23 +144,23 @@ static ebml_spec_t mkv_spec_index[] = {
// cluster
static ebml_spec_t mkv_spec_cluster_fields[] = {
{ MKV_ID_CLUSTERTIMECODE, EBML_UINT, offsetof(mkv_cluster_t, timecode), NULL },
{ MKV_ID_SIMPLEBLOCK, EBML_CUSTOM, 0, mkv_parse_frame },
{ MKV_ID_SIMPLEBLOCK, EBML_CUSTOM | EBML_TRUNCATE, 0, mkv_parse_frame },
{ 0, EBML_NONE, 0, NULL }
};

static ebml_spec_t mkv_spec_cluster[] = {
{ MKV_ID_CLUSTER, EBML_MASTER, 0, mkv_spec_cluster_fields },
{ MKV_ID_CLUSTER, EBML_MASTER | EBML_TRUNCATE, 0, mkv_spec_cluster_fields },
{ 0, EBML_NONE, 0, NULL }
};

static ebml_spec_t mkv_spec_bitrate_estimate_cluster_fields[] = {
{ MKV_ID_CLUSTERTIMECODE, EBML_UINT, offsetof(mkv_cluster_t, timecode), NULL },
{ MKV_ID_SIMPLEBLOCK, EBML_CUSTOM, 0, mkv_parse_frame_estimate_bitrate },
{ MKV_ID_SIMPLEBLOCK, EBML_CUSTOM | EBML_TRUNCATE, 0, mkv_parse_frame_estimate_bitrate },
{ 0, EBML_NONE, 0, NULL }
};

static ebml_spec_t mkv_spec_bitrate_estimate_cluster[] = {
{ MKV_ID_CLUSTER, EBML_MASTER, 0, mkv_spec_bitrate_estimate_cluster_fields },
{ MKV_ID_CLUSTER, EBML_MASTER | EBML_TRUNCATE, 0, mkv_spec_bitrate_estimate_cluster_fields },
{ 0, EBML_NONE, 0, NULL }
};

Expand Down