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smb3: fix setting SecurityFlags when encryption is required

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Setting encryption as required in security flags was broken.
For example (to require all mounts to be encrypted by setting):

  "echo 0x400c5 > /proc/fs/cifs/SecurityFlags"

Would return "Invalid argument" and log "Unsupported security flags"
This patch fixes that (e.g. allowing overriding the default for
SecurityFlags  0x00c5, including 0x40000 to require seal, ie
SMB3.1.1 encryption) so now that works and forces encryption
on subsequent mounts.

Acked-by: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Steve French 2024-07-31 21:38:50 -05:00
parent de9c2c66ad
commit 1b5487aefb
4 changed files with 9 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/admin-guide/cifs/usage.rst
View File

@ -742,7 +742,7 @@ SecurityFlags Flags which control security negotiation and
may use NTLMSSP 0x00080
must use NTLMSSP 0x80080
seal (packet encryption) 0x00040
must seal (not implemented yet) 0x40040
must seal 0x40040
cifsFYI If set to non-zero value, additional debug information
will be logged to the system error log. This field

2
fs/smb/client/cifs_debug.c
View File

@ -1072,7 +1072,7 @@ static int cifs_security_flags_proc_open(struct inode *inode, struct file *file)
static void
cifs_security_flags_handle_must_flags(unsigned int *flags)
{
unsigned int signflags = *flags & CIFSSEC_MUST_SIGN;
unsigned int signflags = *flags & (CIFSSEC_MUST_SIGN | CIFSSEC_MUST_SEAL);
if ((*flags & CIFSSEC_MUST_KRB5) == CIFSSEC_MUST_KRB5)
*flags = CIFSSEC_MUST_KRB5;

8
fs/smb/client/cifsglob.h
View File

@ -1881,7 +1881,7 @@ static inline bool is_replayable_error(int error)
#define CIFSSEC_MAY_SIGN 0x00001
#define CIFSSEC_MAY_NTLMV2 0x00004
#define CIFSSEC_MAY_KRB5 0x00008
#define CIFSSEC_MAY_SEAL 0x00040 /* not supported yet */
#define CIFSSEC_MAY_SEAL 0x00040
#define CIFSSEC_MAY_NTLMSSP 0x00080 /* raw ntlmssp with ntlmv2 */
#define CIFSSEC_MUST_SIGN 0x01001
@ -1891,11 +1891,11 @@ require use of the stronger protocol */
#define CIFSSEC_MUST_NTLMV2 0x04004
#define CIFSSEC_MUST_KRB5 0x08008
#ifdef CONFIG_CIFS_UPCALL
#define CIFSSEC_MASK 0x8F08F /* flags supported if no weak allowed */
#define CIFSSEC_MASK 0xCF0CF /* flags supported if no weak allowed */
#else
#define CIFSSEC_MASK 0x87087 /* flags supported if no weak allowed */
#define CIFSSEC_MASK 0xC70C7 /* flags supported if no weak allowed */
#endif /* UPCALL */
#define CIFSSEC_MUST_SEAL 0x40040 /* not supported yet */
#define CIFSSEC_MUST_SEAL 0x40040
#define CIFSSEC_MUST_NTLMSSP 0x80080 /* raw ntlmssp with ntlmv2 */
#define CIFSSEC_DEF (CIFSSEC_MAY_SIGN | CIFSSEC_MAY_NTLMV2 | CIFSSEC_MAY_NTLMSSP | CIFSSEC_MAY_SEAL)

3
fs/smb/client/smb2pdu.c
View File

@ -82,6 +82,9 @@ int smb3_encryption_required(const struct cifs_tcon *tcon)
if (tcon->seal &&
(tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
return 1;
if (((global_secflags & CIFSSEC_MUST_SEAL) == CIFSSEC_MUST_SEAL) &&
(tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
return 1;
return 0;
}