Re: Big problem on linux 2.0

From: Andrea Arcangeli (andreaat_private)
Date: Tue Dec 14 1999 - 14:09:36 PST

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    On Sat, 11 Dec 1999, visi0n wrote:
    
    >	In my last mail I'd posted a patch for kernel 2.0.38, that  was
    >made against a modified socket.c you need this one for the original kernel
    >(2.0.38). Sorry...
    >
    >@@ -966,8 +966,9 @@
    >        struct msghdr msg;
    >        struct iovec iov;
    >
    >-       if(len<0)
    >+       if(len < 0 || len >= 65468)
    >                return -EINVAL;
    >+
    >        err=verify_area(VERIFY_READ,buff,len);
    >        if(err)
    >                return err;
    
    The above patch doesn't fix the bug, because you can still use
    the other kernel entry points send/sendmsg to feed a big payload
    ip_build_xmit.
    
    Also note that you don't need to restrict to 65467 bytes the max size of a
    packet when the ip options are < 40 bytes.
    
    Andrea
    



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