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    SubjectRe: [PATCH] ELF: implement AT_RANDOM for future glibc use
    On Mon, Oct 06, 2008 at 05:57:48PM -0700, Ulrich Drepper wrote:
    > Kees Cook wrote:
    > > It sounds like it's not very safe,
    >
    > Then investigate it.

    As was suspected, each int is the same.

    > > but on the other hand, glibc doesn't really care?
    >
    > Of course we care. Especially for SUID and uid==0 binaries.

    I meant based on what was said about "if it's as strong as the ASLR
    randomness, it's good enough for this". While the ultimate solution
    would be to bolt a better PRNG into the kernel, is the following good
    enough for now for glibc:

    $ ./rands
    0x2b 0x06 0xb7 0x53 0x2b 0x06 0xb7 0x53 0x2b 0x06 0xb7 0x53 0x2b 0x06 0xb7 0x53
    $ ./rands
    0xc2 0xb5 0x42 0xdc 0xc2 0xb5 0x42 0xdc 0xc2 0xb5 0x42 0xdc 0xc2 0xb5 0x42 0xdc
    $ ./rands
    0x5f 0x39 0xc6 0xc0 0x5f 0x39 0xc6 0xc0 0x5f 0x39 0xc6 0xc0 0x5f 0x39 0xc6 0xc0
    $ ./rands
    0xfb 0x4a 0x82 0xbd 0xfb 0x4a 0x82 0xbd 0xfb 0x4a 0x82 0xbd 0xfb 0x4a 0x82 0xbd

    -Kees

    --
    Kees Cook
    Ubuntu Security Team


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