[FFmpeg-devel] [PATCH] avformat/hls: add macros for iv and key size
James Almer
jamrial at gmail.com
Tue May 11 16:56:50 EEST 2021
On 5/11/2021 10:21 AM, lance.lmwang at gmail.com wrote:
> On Tue, May 11, 2021 at 02:44:34PM +0200, Nicolas George wrote:
>> lance.lmwang at gmail.com (12021-05-11):
>>> From: Limin Wang <lance.lmwang at gmail.com>
>>>
>>> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
>>> ---
>>> libavformat/hls.c | 12 ++++++------
>>> libavformat/hlsenc.c | 19 +++++++++----------
>>> libavformat/internal.h | 2 ++
>>> 3 files changed, 17 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/libavformat/hls.c b/libavformat/hls.c
>>> index 8fc6924..a215c6a 100644
>>> --- a/libavformat/hls.c
>>> +++ b/libavformat/hls.c
>>> @@ -72,7 +72,7 @@ struct segment {
>>> char *url;
>>> char *key;
>>> enum KeyType key_type;
>>> - uint8_t iv[16];
>>> + uint8_t iv[KEYSIZE];
>>> /* associated Media Initialization Section, treated as a segment */
>>> struct segment *init_section;
>>> };
>>> @@ -131,7 +131,7 @@ struct playlist {
>>> unsigned int init_sec_buf_read_offset;
>>>
>>> char key_url[MAX_URL_SIZE];
>>> - uint8_t key[16];
>>> + uint8_t key[KEYSIZE];
>>>
>>> /* ID3 timestamp handling (elementary audio streams have ID3 timestamps
>>> * (and possibly other ID3 tags) in the beginning of each segment) */
>>> @@ -374,7 +374,7 @@ static void handle_variant_args(struct variant_info *info, const char *key,
>>> struct key_info {
>>> char uri[MAX_URL_SIZE];
>>> char method[11];
>>> - char iv[35];
>>> + char iv[KEY_STRING_SIZE + 2]; /* 2 -> 0x */
>>> };
>>>
>>> static void handle_key_args(struct key_info *info, const char *key,
>>> @@ -714,7 +714,7 @@ static int parse_playlist(HLSContext *c, const char *url,
>>> int ret = 0, is_segment = 0, is_variant = 0;
>>> int64_t duration = 0;
>>> enum KeyType key_type = KEY_NONE;
>>> - uint8_t iv[16] = "";
>>> + uint8_t iv[KEYSIZE] = "";
>>> int has_iv = 0;
>>> char key[MAX_URL_SIZE] = "";
>>> char line[MAX_URL_SIZE];
>>> @@ -1252,7 +1252,7 @@ static int open_input(HLSContext *c, struct playlist *pls, struct segment *seg,
>>> if (seg->key_type == KEY_NONE) {
>>> ret = open_url(pls->parent, in, seg->url, &c->avio_opts, opts, &is_http);
>>> } else if (seg->key_type == KEY_AES_128) {
>>> - char iv[33], key[33], url[MAX_URL_SIZE];
>>> + char iv[KEY_STRING_SIZE], key[KEY_STRING_SIZE], url[MAX_URL_SIZE];
>>> if (strcmp(seg->key, pls->key_url)) {
>>> AVIOContext *pb = NULL;
>>> if (open_url(pls->parent, &pb, seg->key, &c->avio_opts, opts, NULL) == 0) {
>>> @@ -1270,7 +1270,7 @@ static int open_input(HLSContext *c, struct playlist *pls, struct segment *seg,
>>> }
>>> ff_data_to_hex(iv, seg->iv, sizeof(seg->iv), 0);
>>> ff_data_to_hex(key, pls->key, sizeof(pls->key), 0);
>>> - iv[32] = key[32] = '\0';
>>> + iv[KEY_STRING_SIZE - 1] = key[KEY_STRING_SIZE - 1] = '\0';
>>> if (strstr(seg->url, "://"))
>>> snprintf(url, sizeof(url), "crypto+%s", seg->url);
>>> else
>>> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
>>> index c43d02c..d72edcf 100644
>>> --- a/libavformat/hlsenc.c
>>> +++ b/libavformat/hlsenc.c
>>> @@ -67,7 +67,6 @@ typedef enum {
>>> CODEC_ATTRIBUTE_WILL_NOT_BE_WRITTEN,
>>> } CodecAttributeStatus;
>>>
>>> -#define KEYSIZE 16
>>> #define LINE_BUFFER_SIZE MAX_URL_SIZE
>>> #define HLS_MICROSECOND_UNIT 1000000
>>> #define BUFSIZE (16 * 1024)
>>> @@ -85,7 +84,7 @@ typedef struct HLSSegment {
>>> unsigned var_stream_idx;
>>>
>>> char key_uri[LINE_BUFFER_SIZE + 1];
>>> - char iv_string[KEYSIZE*2 + 1];
>>> + char iv_string[KEY_STRING_SIZE];
>>>
>>> struct HLSSegment *next;
>>> double discont_program_date_time;
>>> @@ -169,8 +168,8 @@ typedef struct VariantStream {
>>>
>>> char key_file[LINE_BUFFER_SIZE + 1];
>>> char key_uri[LINE_BUFFER_SIZE + 1];
>>> - char key_string[KEYSIZE*2 + 1];
>>> - char iv_string[KEYSIZE*2 + 1];
>>> + char key_string[KEY_STRING_SIZE];
>>> + char iv_string[KEY_STRING_SIZE];
>>>
>>> AVStream **streams;
>>> char codec_attr[128];
>>> @@ -228,8 +227,8 @@ typedef struct HLSContext {
>>> char *key_info_file;
>>> char key_file[LINE_BUFFER_SIZE + 1];
>>> char key_uri[LINE_BUFFER_SIZE + 1];
>>> - char key_string[KEYSIZE*2 + 1];
>>> - char iv_string[KEYSIZE*2 + 1];
>>> + char key_string[KEY_STRING_SIZE];
>>> + char iv_string[KEY_STRING_SIZE];
>>> AVDictionary *vtt_format_options;
>>>
>>> char *method;
>>> @@ -734,8 +733,8 @@ static int do_encrypt(AVFormatContext *s, VariantStream *vs)
>>> }
>>>
>>> if (!*hls->iv_string) {
>>> - uint8_t iv[16] = { 0 };
>>> - char buf[33];
>>> + uint8_t iv[KEYSIZE] = { 0 };
>>> + char buf[KEY_STRING_SIZE];
>>>
>>> if (!hls->iv) {
>>> AV_WB64(iv + 8, vs->sequence);
>>> @@ -743,7 +742,7 @@ static int do_encrypt(AVFormatContext *s, VariantStream *vs)
>>> memcpy(iv, hls->iv, sizeof(iv));
>>> }
>>> ff_data_to_hex(buf, iv, sizeof(iv), 0);
>>> - buf[32] = '\0';
>>> + buf[KEY_STRING_SIZE - 1] = '\0';
>>> memcpy(hls->iv_string, buf, sizeof(hls->iv_string));
>>> }
>>>
>>> @@ -1674,7 +1673,7 @@ static int hls_start(AVFormatContext *s, VariantStream *vs)
>>> AVDictionary *options = NULL;
>>> const char *proto = NULL;
>>> int use_temp_file = 0;
>>> - char iv_string[KEYSIZE*2 + 1];
>>> + char iv_string[KEY_STRING_SIZE];
>>> int err = 0;
>>>
>>> if (c->flags & HLS_SINGLE_FILE) {
>>> diff --git a/libavformat/internal.h b/libavformat/internal.h
>>> index d57e63c..2aefac0 100644
>>> --- a/libavformat/internal.h
>>
>>> +++ b/libavformat/internal.h
>>> @@ -28,6 +28,8 @@
>>> #include "os_support.h"
>>>
>>> #define MAX_URL_SIZE 4096
>>> +#define KEYSIZE 16
>>> +#define KEY_STRING_SIZE (KEYSIZE * 2 + 1)
>>
>> So, anything using internal.h can only deal with 128 bits keys? Seems
>> wrong.
>
> Of course, it's not my intention. It's used by hls only and I haven't find a common header
> for hls.c and hlsenc.c.
You can create a new hls.h header for this purpose just fine.
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