[asterisk-bugs] [JIRA] (ASTERISK-23713) Voicemail on FS overwrites last message when last index = MSGLIMIT

[Miguel Tavares (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-23713?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=218103#comment-218103 ] 

Miguel Tavares commented on ASTERISK-23713:
-------------------------------------------

Hi.

Some small examples of behavior. "map" represents the messages that exist in the file system (position 0 corresponds to msg0000, position 1 is msg0001, etc). "last msg index" is the return of calling the last_msg_index function and the file name is obvious.

With vmu->maxmsg=5 and MAXMSGLIMIT=10:

map = (0,0,0,0,0,0,0,0,0,0)
last msg index = -1
creating file msg0000.(txt,wav)

map = (1,0,0,0,1,0,0,0,0,0)
last msg index = 4
creating file msg0005.(txt,wav)

map = (1,0,0,0,1,1,0,0,0,0)
last msg index = 4
creating file msg0005.(txt,wav)

Notice how the user has only 3 messages but the next message will overwrite message 5.

> Voicemail on FS overwrites last message when last index = MSGLIMIT
> ------------------------------------------------------------------
>
>                 Key: ASTERISK-23713
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-23713
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Applications/app_voicemail
>    Affects Versions: SVN, 12.2.0
>         Environment: app_voicemail delivery on filesystem.
> Any asterisk supported platform is probably affected.
>            Reporter: Miguel Tavares
>            Assignee: Miguel Tavares
>
> When leaving a voicemail the function last_message_index will stop at index only until the default or configured max messages (vmu->maxmsg) although it should continue until MAXMSGLIMIT.
> Example, let's say the asterisk admin set the maximum messages to 10, the user received 10 messages and then deleted 9 apart from the last one. In the filesystem the files msg0010.txt and msg0010.wav will be present.
> The last_message_index will detect that that's the only message available but then  when finding out what's the index it will stop at 9 (the configure maximum when counting from 0) and return that as the last message index, making he voicemail app to overwrite the previous existing last message.
> Possible fix, in app_voicemail.c
> {noformat}
> 112a113
> > #include <string.h>
> 4434c4435
> <       unsigned char map[MAXMSGLIMIT] = "";
> ---
> >       unsigned char map[MAXMSGLIMIT];
> 4440a4442
> >     memset (map, 0, sizeof(map)); //set the memory to 0 for Safety sake.
> 4458c4460
> <       for (x = 0; x < vmu->maxmsg; x++) {
> ---
> >       for (x = 0; x < MAXMSGLIMIT; x++) {
> {noformat}
> The important change is running the for cycle until MAXMSGLIMIT but as far as I know there's no guarantee that memory allocated in the stack is zeroed so that's why I also included the memset call.



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