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    SubjectRe: [SECURITY] FDs 0, 1, 2 for SUID/SGID programs
    * Florian Weimer (Weimer@CERT.Uni-Stuttgart.DE) wrote:
    > probably affects
    > Linux, too (if a SUID/SGID program is invoked with FD 2 closed, error
    > messages might be written to a file opened by the program ).

    AFAIK, the standards clearly specify behaviour wrt. open file descriptors
    and clone-on-exec file descriptors across execve(). However, there
    is nothing specified when it comes to closed file descpriptors across
    execve(), notably FD's 0, 1 and 2 are certainly not required to be open
    across an execve() of a SUID/SGID applictaion. One could argue that
    SUID/SGID apps that trust the file descriptors they inherit across exec()
    are buggy.

    Having said that, there are a number of implementations of this type
    of protection for the linux kernel stemming from the Openwall project.
    If you are interested, see: (CONFIG_SECURE_FD_0_1_2) (CONFIG_OWLSM_FD) (CONFIG_GRKERNSEC_FD)

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      Last update: 2005-03-22 13:25    [W:0.021 / U:5.788 seconds]
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