Re: [PATCH] alignment issue with ipchains

From: NIIBE Yutaka (gniibe@chroot.org)
Date: Fri Sep 08 2000 - 23:18:28 EDT

  • Next message: Ragnar Hojland Espinosa: "Re: Whining about MIME formatted email"

    Hi David,

    I'd like to explain my point clearly. My point is that accessing with
    get_user as int is questionable. In my case, it's string. I don't
    think all the string argment to the kernel should be aligned.

    David S. Miller wrote:
    > Why not make sure in the user tools that the argument is properly
    > aligned to 4 bytes?

    Because (I think) it's not needed by the interface definition.

    > I would really like to see specific examples of the failure before I
    > consider this issue further.

    OK, here's example (I'm talking about ipchains 1.3.8 or 9):

       # ipchains -F input

    Here, on SuperH, the string of command line argument "input" is not
    aligned to 4-byte boundary. The argument to main argv ("input") goes
    through the setsockopt.

        main --> flush_entries --> libipfwc.c:ipfwc_flush_entries
            --> do_setsockopt --> setsockopt

    For the optname IP_FW_APPEND...IP_FW_MASQ_CTL, the type of the value
    is not integer but string. Accessing as int is rather violent.

    I guess that on Sparc or Alpha the command line argument string is
    4-byte aligned. 

    -- 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/

    This archive was generated by hypermail 2b29 : Fri Sep 08 2000 - 23:20:58 EDT