[vlc-devel] [PATCH] srt: parse srt parameters from url

Thomas Guillem thomas at gllm.fr
Wed Mar 6 16:39:33 CET 2019


On Wed, Mar 6, 2019, at 16:34, Aaron Boxer wrote:
> Thank you, Tristan. So, I see that vlc_credential API is a way of extracting the user credentials from the URL.
> But, there would still be the issue of credentials being displayed in window, logs etc, as mentioned by Remi ?

Hello,
This API handle credential from URL yes, but it's not its main purpose. This API handle interaction with the user (from a dialog generally) to ask for a password. This API will also save the password in VLC internal memory keystore and/or in the OS one (kwallet and co) if the user want to.

> 
> On Wed, Mar 6, 2019 at 10:20 AM Tristan Matthews <tmatth at videolan.org> wrote:
>> On Wed, Mar 6, 2019 at 10:04 AM Aaron Boxer <boxerab at gmail.com> wrote:
>>  >
>>  > Thanks, Remi. Is there another better way of getting a user-configured passphrase to the srt module ?
>> 
>>  I think you want the vlc_credential API, see e.g.,
>> https://git.videolan.org/?p=vlc.git;a=blob;f=modules/access/http.c;h=56d75687e27f10a6c1ef33cd32178dcc857e4136;hb=HEAD#l304
>> 
>>  Best,
>>  -t
>> 
>>  > On Wed, Mar 6, 2019 at 5:57 AM Rémi Denis-Courmont <remi at remlab.net> wrote:
>>  >>
>>  >> Hi,
>>  >>
>>  >> Passing passwords in URLs is well-documented as a terrible idea. In VLC's case, the passphrase will show up in the OSD title, window title, logs, etc...
>>  >>
>>  >> Le 5 mars 2019 23:42:14 GMT+02:00, Aaron Boxer <boxerab at gmail.com> a écrit :
>>  >>>
>>  >>> Parse pass phrase and latency from url for incoming srt stream
>>  >>>
>>  >>>
>>  >>> diff --git a/modules/access/srt.c b/modules/access/srt.c
>>  >>> index d8d8cbe659..55c0efc201 100644
>>  >>> --- a/modules/access/srt.c
>>  >>> +++ b/modules/access/srt.c
>>  >>> @@ -37,6 +37,9 @@
>>  >>>
>>  >>> #include <srt/srt.h>
>>  >>>
>>  >>> +const char* SRT_PARAM_PASSPHRASE = "passphrase";
>>  >>> +const char* SRT_PARAM_LATENCY = "latency";
>>  >>> +
>>  >>> /* libsrt defines default packet size as 1316 internally
>>  >>> * so srt module takes same value. */
>>  >>> #define SRT_DEFAULT_CHUNK_SIZE 1316
>>  >>> @@ -70,6 +73,85 @@ typedef struct
>>  >>> int i_chunks; /* Number of chunks to allocate in the next read */
>>  >>> } stream_sys_t;
>>  >>>
>>  >>> +
>>  >>> +
>>  >>> +struct parsed_param {
>>  >>> + char *key;
>>  >>> + char *val;
>>  >>> +};
>>  >>> +
>>  >>> +static inline char *
>>  >>> +find(char *str, char find)
>>  >>> +{
>>  >>> + str = strchr(str, find);
>>  >>> + if (NULL == str) {
>>  >>> + return NULL;
>>  >>> + }
>>  >>> + return str + 1;
>>  >>> +}
>>  >>> +
>>  >>> +static inline char *
>>  >>> +find_query(char *str)
>>  >>> +{
>>  >>> + return find(str, '?');
>>  >>> +}
>>  >>> +
>>  >>> +/**
>>  >>> + * Parse a query string into an array of key/value structs.
>>  >>> + *
>>  >>> + * The query string should be a null terminated string of parameters separated by
>>  >>> + * a delimiter. Each parameter are checked for the equal sign character. If it
>>  >>> + * appears in the parameter, it will be used as a null terminator and the part
>>  >>> + * that comes after it will be the value of the parameter.
>>  >>> + *
>>  >>> + *
>>  >>> + * param: query: the query string to parse. The string will be modified.
>>  >>> + * param: delimiter: the character that separates the key/value pairs from each other.
>>  >>> + * param: params: an array of parsed_param structs to hold the result.
>>  >>> + * param: max_params: maximum number of parameters to parse.
>>  >>> + *
>>  >>> + * Return: the number of parsed items. -1 if there was an error.
>>  >>> + */
>>  >>> +static int
>>  >>> +srt_url_parse_query(char *query, char delimiter, struct parsed_param *params, int max_params)
>>  >>> +{
>>  >>> + int i = 0;
>>  >>> +
>>  >>> + if (!query || *query == '\0')
>>  >>> + {
>>  >>> + return -1;
>>  >>> + }
>>  >>> + if (!params || max_params == 0)
>>  >>> + {
>>  >>> + return 0;
>>  >>> + }
>>  >>> +
>>  >>> + params[i++].key = query;
>>  >>> + while (i < max_params && NULL != (query = strchr(query, delimiter)))
>>  >>> + {
>>  >>> + *query = '\0';
>>  >>> + params[i].key = ++query;
>>  >>> + params[i].val = NULL;
>>  >>> +
>>  >>> + /* Go back and split previous param if one exists */
>>  >>> + if (i > 0)
>>  >>> + {
>>  >>> + if ((params[i - 1].val = strchr(params[i - 1].key, '=')) != NULL)
>>  >>> + {
>>  >>> + *(params[i - 1].val)++ = '\0';
>>  >>> + }
>>  >>> + }
>>  >>> + i++;
>>  >>> + }
>>  >>> + /* Go back and split last param */
>>  >>> + if ((params[i - 1].val = strchr(params[i - 1].key, '=')) != NULL)
>>  >>> + {
>>  >>> + *(params[i - 1].val)++ = '\0';
>>  >>> + }
>>  >>> + return i;
>>  >>> +}
>>  >>> +
>>  >>> +
>>  >>> static void srt_wait_interrupted(void *p_data)
>>  >>> {
>>  >>> stream_t *p_stream = p_data;
>>  >>> @@ -115,9 +197,11 @@ static int Control(stream_t *p_stream, int i_query, va_list args)
>>  >>>
>>  >>> static bool srt_schedule_reconnect(stream_t *p_stream)
>>  >>> {
>>  >>> - int i_latency;
>>  >>> + int i_latency=-1;
>>  >>> int stat;
>>  >>> char *psz_passphrase = NULL;
>>  >>> + bool parsed_passphrase = false;
>>  >>> + char *url = NULL;
>>  >>>
>>  >>> struct addrinfo hints = {
>>  >>> .ai_socktype = SOCK_DGRAM,
>>  >>> @@ -153,6 +237,38 @@ static bool srt_schedule_reconnect(stream_t *p_stream)
>>  >>> goto out;
>>  >>> }
>>  >>>
>>  >>> + /* Parse URL parameters */
>>  >>> + if (p_stream->psz_url && strlen(p_stream->psz_url) < 512)
>>  >>> + {
>>  >>> + char* query = NULL;
>>  >>> + struct parsed_param params[32];
>>  >>> + int num_params = 0;
>>  >>> + int i=0;
>>  >>> + size_t url_size = strlen(p_stream->psz_url)+1;
>>  >>> +
>>  >>> + url = malloc(url_size);
>>  >>> + url[url_size-1] = 0;
>>  >>> + strcpy(url, p_stream->psz_url);
>>  >>> + query = find_query(url);
>>  >>> + if (query)
>>  >>> + {
>>  >>> + num_params = srt_url_parse_query(query,'&', params, sizeof(params)/sizeof(struct parsed_param) );
>>  >>> + if (num_params > 0) {
>>  >>> + for (i = 0; i < num_params; ++i)
>>  >>> + {
>>  >>> + if (strcmp(params[i].key, SRT_PARAM_PASSPHRASE) == 0)
>>  >>> + {
>>  >>> + psz_passphrase = params[i].val;
>>  >>> + parsed_passphrase = true;
>>  >>> + }
>>  >>> + else if (strcmp(params[i].key, SRT_PARAM_LATENCY) == 0)
>>  >>> + i_latency = atoi(params[i].val);
>>  >>> + }
>>  >>> + }
>>  >>> + }
>>  >>> + }
>>  >>> +
>>  >>> +
>>  >>> /* Make SRT non-blocking */
>>  >>> srt_setsockopt( p_sys->sock, 0, SRTO_SNDSYN,
>>  >>> &(bool) { false }, sizeof( bool ) );
>>  >>> @@ -168,11 +284,13 @@ static bool srt_schedule_reconnect(stream_t *p_stream)
>>  >>> &(int) { 0 }, sizeof( int ) );
>>  >>>
>>  >>> /* Set latency */
>>  >>> - i_latency = var_InheritInteger( p_stream, "latency" );
>>  >>> + if (i_latency == -1)
>>  >>> + i_latency = var_InheritInteger( p_stream, SRT_PARAM_LATENCY );
>>  >>> srt_setsockopt( p_sys->sock, 0, SRTO_TSBPDDELAY,
>>  >>> &i_latency, sizeof( int ) );
>>  >>>
>>  >>> - psz_passphrase = var_InheritString( p_stream, "passphrase" );
>>  >>> + if (!psz_passphrase)
>>  >>> + psz_passphrase = var_InheritString( p_stream, SRT_PARAM_PASSPHRASE );
>>  >>> if ( psz_passphrase != NULL && psz_passphrase[0] != '\0')
>>  >>> {
>>  >>> int i_key_length = var_InheritInteger( p_stream, "key-length" );
>>  >>> @@ -211,7 +329,11 @@ out:
>>  >>> }
>>  >>>
>>  >>> freeaddrinfo( res );
>>  >>> - free( psz_passphrase );
>>  >>> + if (!parsed_passphrase)
>>  >>> + {
>>  >>> + free( psz_passphrase );
>>  >>> + }
>>  >>> + free(url);
>>  >>>
>>  >>> return !failed;
>>  >>> }
>>  >>> @@ -422,8 +544,8 @@ vlc_module_begin ()
>>  >>> N_("SRT chunk size (bytes)"), NULL, true )
>>  >>> add_integer( "poll-timeout", SRT_DEFAULT_POLL_TIMEOUT,
>>  >>> N_("Return poll wait after timeout milliseconds (-1 = infinite)"), NULL, true )
>>  >>> - add_integer( "latency", SRT_DEFAULT_LATENCY, N_("SRT latency (ms)"), NULL, true )
>>  >>> - add_password("passphrase", "", N_("Password for stream encryption"), NULL)
>>  >>> + add_integer( SRT_PARAM_LATENCY, SRT_DEFAULT_LATENCY, N_("SRT latency (ms)"), NULL, true )
>>  >>> + add_password(SRT_PARAM_PASSPHRASE, "", N_("Password for stream encryption"), NULL)
>>  >>> add_integer( "key-length", SRT_DEFAULT_KEY_LENGTH,
>>  >>> SRT_KEY_LENGTH_TEXT, SRT_KEY_LENGTH_TEXT, false )
>>  >>> change_integer_list( srt_key_lengths, srt_key_length_names )
>>  >>>
>>  >>
>>  >> --
>>  >> Envoyé de mon appareil Android avec Courriel K-9 Mail. Veuillez excuser ma brièveté.
>>  >
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