diff options
| -rw-r--r-- | fs/cifs/cifs_debug.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c index 0315824bbf01..f3ac4154cbb6 100644 --- a/fs/cifs/cifs_debug.c +++ b/fs/cifs/cifs_debug.c @@ -597,6 +597,32 @@ 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) { @@ -650,6 +676,8 @@ 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) { |