On Tue, 28 May 2013 08:12:00 -0400 Jeff Layton <[email protected]> wrote:
> The cifs.ko SecurityFlags interface wins my award for worst-designed > interface ever, but we're sort of stuck with it since it's documented > and people do use it (even if it doesn't work correctly). > > Case in point -- you can specify multiple sets of "MUST" flags. It makes > absolutely no sense, but you can do it. > > What should the effect be in such a case? No one knows or seems to have > considered this so far, so let's define it now. If you try to specify > multiple MUST flags, clear any other MAY or MUST bits except for the > ones that involve signing. > > Signed-off-by: Jeff Layton <[email protected]> > Reviewed-by: Pavel Shilovsky <[email protected]> Steve, I noticed you had merged all of the patches in this series except this one. Did you find a problem with it or did you just not get to it yet? Thanks, > --- > fs/cifs/cifs_debug.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c > index 856f8f5..d21339a 100644 > --- a/fs/cifs/cifs_debug.c > +++ b/fs/cifs/cifs_debug.c > @@ -595,6 +595,32 @@ static int cifs_security_flags_proc_open(struct inode > *inode, struct file *file) > return single_open(file, cifs_security_flags_proc_show, NULL); > } > > +/* > + * Ensure that if someone sets a MUST flag, that we disable all other MAY > + * flags except for the ones corresponding to the given MUST flag. If there > are > + * multiple MUST flags, then try to prefer more secure ones. > + */ > +static void > +cifs_security_flags_handle_must_flags(unsigned int *flags) > +{ > + unsigned int signflags = *flags & CIFSSEC_MUST_SIGN; > + > + if ((*flags & CIFSSEC_MUST_KRB5) == CIFSSEC_MUST_KRB5) > + *flags = CIFSSEC_MUST_KRB5; > + else if ((*flags & CIFSSEC_MUST_NTLMSSP) == CIFSSEC_MUST_NTLMSSP) > + *flags = CIFSSEC_MUST_NTLMSSP; > + else if ((*flags & CIFSSEC_MUST_NTLMV2) == CIFSSEC_MUST_NTLMV2) > + *flags = CIFSSEC_MUST_NTLMV2; > + else if ((*flags & CIFSSEC_MUST_NTLM) == CIFSSEC_MUST_NTLM) > + *flags = CIFSSEC_MUST_NTLM; > + else if ((*flags & CIFSSEC_MUST_LANMAN) == CIFSSEC_MUST_LANMAN) > + *flags = CIFSSEC_MUST_LANMAN; > + else if ((*flags & CIFSSEC_MUST_PLNTXT) == CIFSSEC_MUST_PLNTXT) > + *flags = CIFSSEC_MUST_PLNTXT; > + > + *flags |= signflags; > +} > + > static ssize_t cifs_security_flags_proc_write(struct file *file, > const char __user *buffer, size_t count, loff_t *ppos) > { > @@ -648,6 +674,8 @@ static ssize_t cifs_security_flags_proc_write(struct file > *file, > return -EINVAL; > } > > + cifs_security_flags_handle_must_flags(&flags); > + > /* flags look ok - update the global security flags for cifs module */ > global_secflags = flags; > if (global_secflags & CIFSSEC_MUST_SIGN) { -- Jeff Layton <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
