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    Subjectexecve strangeness
    Try this, as root:

    [root@mnm akpm]# /var/log/messages
    bash: /var/log/messages: Text file busy

    Strange return value, that.

    It happens because vfs_permission() sees CAP_DAC_OVERRIDE
    and returns "yes" on a file which has no `x' bits set.
    Then open_exec() falls through to deny_write_access() which
    sees that the file is open for writing.

    If the file is _not_ open for writing then the "WTF" test in
    prepare_binprm() is what stops us from executing the file. So
    the test there is definitely needed.

    Moving the "WTF" test into open_exec() definitely fixes things
    up, but I think the real bug is in vfs_permission().



    --- linux-2.4.6-pre6/fs/exec.c Wed May 2 22:00:06 2001
    +++ lk-ext3/fs/exec.c Mon Jul 2 02:01:52 2001
    @@ -349,6 +349,8 @@
    file = ERR_PTR(-EACCES);
    if (!IS_NOEXEC(inode) && S_ISREG(inode->i_mode)) {
    int err = permission(inode, MAY_EXEC);
    + if (!err && !(inode->i_mode & 0111))
    + err = -EACCES;
    file = ERR_PTR(err);
    if (!err) {
    file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
    @@ -606,7 +608,10 @@
    struct inode * inode = bprm->file->f_dentry->d_inode;

    mode = inode->i_mode;
    - /* Huh? We had already checked for MAY_EXEC, WTF do we check this? */
    + /*
    + * Check execute perms again - if the caller has CAP_DAC_OVERRIDE,
    + * vfs_permission lets a non-executable through
    + */
    if (!(mode & 0111)) /* with at least _one_ execute bit set */
    return -EACCES;
    if (bprm->file->f_op == NULL)
    -
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