[Samba] stack smashing problem
Matthias et Laura
mattelau at mattelau.net
Mon May 15 22:34:02 GMT 2006
Jeremy Allison a écrit :
>On Mon, May 15, 2006 at 12:07:10AM +0200, Matthias et Laura wrote:
>>I have a problem with my smbd daemon, on a hardened linux from scratch
>>glibc 2.3.6 with fstack protector
>>grsecurity 2.1.8 patch
>>gcc 3.4.5 with stack smashing protector
>>When starting smbd, I do not have any problem, the daemon is running,
>>but all his childs die.
>>I have the following log message, repeated several times :
>>smbd: stack smashing attack in function open_sockets_smbd()
>>So it seems that the open_sockets_smbd function does something that the
>>stack smashing protection find weird.
>>Do you have any idea ?
>More details please. What is the "stack smashing protector" and
>what does it do ?
Did a little debugging tonight :
The problem stands in the smbd/server.c file, open_sockets_smbd
function, close_low_fds(False); call ( line 414 )
The close_low_fds function is declared in the lib/util.c file
And the stack smashing problem stands on the close(1) statement ( at the
begining of the function )
I commented the whole content of the close_low_fds function
Then another stack smashing pb on the 'return True' statement line 436
I commented this line and no stack smashing pb anymore : weird
But my shares do not work neither ;-(
Will try to ask help from the anti stack smashing guys ... if I can find
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