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zardus / preeny

Some helpful preload libraries for pwning stuff.
BSD 2-Clause "Simplified" License
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You might want to fill the addr struct passed to accept #12

Open junxzm1990 opened 9 years ago

junxzm1990 commented 9 years ago

The standard accept function will fill the "addr struct" (passed as argument) with the address of the peer socket. This is not done by the "accept" in desock.c. Some applications will not continue executing until the "addr struct" is filled. For instance, the latest version of nginx will check the address of the peer socket (I tried it with select mode but not sure about other modes).

zardus commented 9 years ago

Good catch. Do you have a fixed implementation you could PR, by any chance?

junxzm1990 commented 9 years ago

I think you can fill the "addr struct" with a fake address (e.g. INADDR_ANY) and set the "socklen_t * addrlen" correspondingly. That's what I did.

zardus commented 9 years ago

Could you push your code as a PR?

junxzm1990 commented 9 years ago

I am still "borrowing" the preeny code. When all set, I will PR.

zardus commented 9 years ago

Awesome, thanks :-)

gsingh93 commented 8 years ago

7 months and still no PR :p

Running into the same issue with nginx.

gsingh93 commented 8 years ago

There are some other interesting issues that might be worth looking into. While I'm having the same issue with addr not being set, I'm finding that eventually it does get set after about a minute... I'm not sure if something in the code is causing it to fall back to original_accept, but I'll try to investigate more.

Just to prove I'm not crazy here, occasionally the addr_text.len != 0 check passes and I see this in my nginx logs: unix: - - [04/Apr/2016:04:24:02 +0000] "GET / HTTP/1.0" 200 612 "-" "-". The addr_text.data was set to unix