You're right Udo, I didn't realize the condition of buffer being a symlink was not tested before calling readlink . I'm glad I posted this here before using it... ;-).
Thanks,
atinar
Beiträge von atinar
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Hello,
First of all, excuse me for posting in English, but I've not seen nothing related to patches in international forums. Feel free to reply in German.In tools.c, when removing a file that is a symlink, the buffer size allocated for the target file path is twice the size of the link path. Under certain circumstances the supposition this is enough is wrong.
In countries like mine (allow me to omit which one it is...) there are many TV stations which have serious problems with the quality of the EPG they provide. In particular, they don't seem to understand the difference between the "short description" and "description" fields and are prone to fill the first one with the second one. If you are recording a series episode you may end with a filename which contains as much of the description as possible. When you change the name of the recording for a more reasonable one, the problem is served.
I think that a call to stat, should be done instead. This patch is for an old vdr, but I think with minor changes it still applies:
Diff
Alles anzeigen--- VDR-ori/tools.c 2010-06-20 00:37:37.000000000 +0200 +++ VDR-bui/tools.c 2010-06-20 01:01:18.000000000 +0200 @@ -374,22 +374,29 @@ char *buffer; asprintf(&buffer, "%s/%s", FileName, e->d_name); if (FollowSymlinks) { - int size = strlen(buffer) * 2; // should be large enough - char *l = MALLOC(char, size); - int n = readlink(buffer, l, size); - if (n < 0) { - if (errno != EINVAL) - LOG_ERROR_STR(buffer); + struct stat st2; + if (stat(buffer, &st2) == 0) { + int size = st2.st_size + 1; + char *l = MALLOC(char, size); + int n = readlink(buffer, l, st2.st_size); + if (n < 0) { + if (errno != EINVAL) + LOG_ERROR_STR(buffer); + } + else if (n < size) { + l[n] = 0; + dsyslog("removing %s", l); + if (remove(l) < 0) + LOG_ERROR_STR(l); + } + else + esyslog("ERROR: symlink name length (%d) exceeded anticipated buffer size (%d)", n, size); + free(l); } - else if (n < size) { - l[n] = 0; - dsyslog("removing %s", l); - if (remove(l) < 0) - LOG_ERROR_STR(l); + else if (errno != ENOENT) { + LOG_ERROR_STR(FileName); + return false; } - else - esyslog("ERROR: symlink name length (%d) exceeded anticipated buffer size (%d)", n, size); - free(l); } dsyslog("removing %s", buffer); if (remove(buffer) < 0)