| From: Thomas Reitelbach <[EMAIL PROTECTED]>
| On Thursday 30 December 2004 01:25, D. Hugh Redelmeier wrote:
| > It isn't clear how to migrate an old .licq to 1.30. Certainly, a pure
| > copy does not work (hard to copy a FIFO). Also, the plugin names are
| > in a configuration file, and they've changed.
|
| Hm, no, they did not change. Licq does update the configuration files
| automatically when it detects old config-files.
My user showed up. licq crashed (segv) when using his old configs.
Bottom line: there is a bug in 1.30's user.cpp that causes a crash in
line 625 (routine CUserManager::Load). This code deals with lines in
~/.licq/users.conf. It wants to split the user number from the
protocol ID:
sz = strrchr(szFile, '.');
strncpy(szId, szFile, sz - szFile);
szId[sz - szFile] = '\0';
nPPID = (*(sz+1)) << 24 | (*(sz+2)) << 16 | (*(sz+3)) << 8 | (*(sz+4));
Now: think what happens if there is no '.' in the line. sz will be
NULL. The strncmp will be passed an invalid length.
szId[somethingawful] will be set to NUL.
My user's user.conf lines had no '.'. Boom.
For now, we just added .Licq to each line.
Another potential bug: what if there are not 3 characters after the .
AND the line is really long. The code for calculating nPPID may reach
past the end of szFile.
================
I had quite a lot of trouble debugging this. I've never used gdb on
c++ code before. I could not get it to examine local variables. I
did rebuild all of licq after doing:
./configure --enable-debug
This helped: gdb then did know the line numbers for crashes. Anybody
know how to display, for example, sz or szId when at a breakpoint in
the above code? "print sz" failed because gdb claimed no to know the
variable (but "print i" worked). I wonder if the -O2 flag caused
variable info to be washed away.
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