[FFmpeg-devel] Ignore expired cookies

Signed-off-by: Micah Galizia <micahgalizia@gmail.com>
---
 libavformat/http.c | 43 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 39 insertions(+), 4 deletions(-)

On Sat, 25 Mar 2017 10:31:00 -0400
Micah Galizia <micahgalizia@gmail.com> wrote:

> Signed-off-by: Micah Galizia <micahgalizia@gmail.com>
> ---
>  libavformat/http.c | 43 +++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 39 insertions(+), 4 deletions(-)
> 
> diff --git a/libavformat/http.c b/libavformat/http.c
> index 293a8a7..f7d1925 100644
> --- a/libavformat/http.c
> +++ b/libavformat/http.c
> @@ -29,6 +29,7 @@
>  #include "libavutil/avstring.h"
>  #include "libavutil/opt.h"
>  #include "libavutil/time.h"
> +#include "libavutil/parseutils.h"
>  
>  #include "avformat.h"
>  #include "http.h"
> @@ -48,6 +49,8 @@
>  #define MAX_REDIRECTS 8
>  #define HTTP_SINGLE   1
>  #define HTTP_MUTLI    2
> +#define MAX_EXPIRY    30
> +#define WHITESPACES " \n\t\r"
>  typedef enum {
>      LOWER_PROTO,
>      READ_HEADERS,
> @@ -877,15 +880,20 @@ static int get_cookies(HTTPContext *s, char **cookies, const char *path,
>  
>      *cookies = NULL;
>      while ((cookie = av_strtok(set_cookies, "\n", &next))) {
> -        int domain_offset = 0;
> +        int domain_offset = 0, expired = 0;
>          char *param, *next_param, *cdomain = NULL, *cpath = NULL, *cvalue = NULL;
> +        char exp_buf[MAX_EXPIRY];
>          set_cookies = NULL;
>  
>          // store the cookie in a dict in case it is updated in the response
>          if (parse_cookie(s, cookie, &s->cookie_dict))
>              av_log(s, AV_LOG_WARNING, "Unable to parse '%s'\n", cookie);
>  
> -        while ((param = av_strtok(cookie, "; ", &next_param))) {
> +        while ((param = av_strtok(cookie, ";", &next_param))) {
> +
> +            // move past any leading whitespace
> +            param += strspn(param, WHITESPACES);
> +
>              if (cookie) {
>                  // first key-value pair is the actual cookie value
>                  cvalue = av_strdup(param);
> @@ -899,6 +907,33 @@ static int get_cookies(HTTPContext *s, char **cookies, const char *path,
>                  int leading_dot = (param[7] == '.');
>                  av_free(cdomain);
>                  cdomain = av_strdup(&param[7+leading_dot]);
> +            } else if (!av_strncasecmp("expires=", param, 8)) {
> +                int i, j, exp_len;
> +                struct tm tm_buf = {0};
> +                char *expiry = &param[8];
> +
> +                // strip off any punctuation or whitespace
> +                exp_len = strlen(expiry);
> +                for (i = 0, j = 0; i < exp_len; i++) {
> +                    if ((expiry[i] >= '0' && expiry[i] <= '9') ||
> +                        (expiry[i] >= 'A' && expiry[i] <= 'Z') ||
> +                        (expiry[i] >= 'a' && expiry[i] <= 'z')) {
> +                        exp_buf[j] = expiry[i];
> +                        j++;
> +                    }
> +                }
> +                exp_buf[j] = '\0';

This can overflow sizeof(exp_buf).

> +
> +                // move the string beyond the day of week
> +                i = 0;
> +                while ((exp_buf[i] < '0' || exp_buf[i] > '9') && (i < j))
> +                    i++;
> +
> +                if (av_small_strptime(&exp_buf[i], "%d%b%Y%H%M%SGMT", &tm_buf)) {
> +                    time_t now = av_gettime() / 1000000;

I don't know if av_gettime() has the same time base...

> +                    if (av_timegm(&tm_buf) < now)
> +                        expired = 1;
> +                }
>              } else {
>                  // ignore unknown attributes
>              }
> @@ -907,9 +942,9 @@ static int get_cookies(HTTPContext *s, char **cookies, const char *path,
>              cdomain = av_strdup(domain);
>  
>          // ensure all of the necessary values are valid
> -        if (!cdomain || !cpath || !cvalue) {
> +        if (expired || !cdomain || !cpath || !cvalue ) {
>              av_log(s, AV_LOG_WARNING,
> -                   "Invalid cookie found, no value, path or domain specified\n");
> +                   "Invalid cookie found, expired or no value, path or domain specified\n");
>              goto done_cookie;
>          }
>

On Sat, Mar 25, 2017 at 10:51 AM, wm4 <nfxjfg@googlemail.com> wrote:

<SNIP>

> This can overflow sizeof(exp_buf).

Sorry, new patch cleans that up.

>> +
>> +                // move the string beyond the day of week
>> +                i = 0;
>> +                while ((exp_buf[i] < '0' || exp_buf[i] > '9') && (i < j))
>> +                    i++;
>> +
>> +                if (av_small_strptime(&exp_buf[i], "%d%b%Y%H%M%SGMT", &tm_buf)) {
>> +                    time_t now = av_gettime() / 1000000;
>
> I don't know if av_gettime() has the same time base...

I had to double-check but I think it's correct as it is. The av_gettime() is based on the time since the epoch, which is already in GMT/UTC. The cookies timestamp is also expressed in GMT/UTC per the HTTP spec (and per av_timegm), so I believe these are comparable.

If you were not talking about the timezones when you said "same base", I'm not entirely sure what you're getting at. I tested on my system and av_gettime()/1000000 returns the same value as time(NULL).

Thanks again.