lwn.git/fs/cifs, branch v4.2.4

cifs: use server timestamp for ntlmv2 authentication

2015-10-22T21:49:27+00:00

commit 98ce94c8df762d413b3ecb849e2b966b21606d04 upstream. Linux cifs mount with ntlmssp against an Mac OS X (Yosemite 10.10.5) share fails in case the clocks differ more than +/-2h: digest-service: digest-request: od failed with 2 proto=ntlmv2 digest-service: digest-request: kdc failed with -1561745592 proto=ntlmv2 Fix this by (re-)using the given server timestamp for the ntlmv2 authentication (as Windows 7 does). A related problem was also reported earlier by Namjae Jaen (see below): Windows machine has extended security feature which refuse to allow authentication when there is time difference between server time and client time when ntlmv2 negotiation is used. This problem is prevalent in embedded enviornment where system time is set to default 1970. Modern servers send the server timestamp in the TargetInfo Av_Pair structure in the challenge message [see MS-NLMP 2.2.2.1] In [MS-NLMP 3.1.5.1.2] it is explicitly mentioned that the client must use the server provided timestamp if present OR current time if it is not Reported-by: Namjae Jeon Signed-off-by: Peter Seiderer Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

Do not fall back to SMBWriteX in set_file_size error cases

2015-10-22T21:49:24+00:00

commit 646200a041203f440fb6fcf9cacd9efeda9de74c upstream. The error paths in set_file_size for cifs and smb3 are incorrect. In the unlikely event that a server did not support set file info of the file size, the code incorrectly falls back to trying SMBWriteX (note that only the original core SMB Write, used for example by DOS, can set the file size this way - this actually does not work for the more recent SMBWriteX). The idea was since the old DOS SMB Write could set the file size if you write zero bytes at that offset then use that if server rejects the normal set file info call. Fortunately the SMBWriteX will never be sent on the wire (except when file size is zero) since the length and offset fields were reversed in the two places in this function that call SMBWriteX causing the fall back path to return an error. It is also important to never call an SMB request from an SMB2/sMB3 session (which theoretically would be possible, and can cause a brief session drop, although the client recovers) so this should be fixed. In practice this path does not happen with modern servers but the error fall back to SMBWriteX is clearly wrong. Removing the calls to SMBWriteX in the error paths in cifs_set_file_size Pointed out by PaX/grsecurity team Signed-off-by: Steve French Reported-by: PaX Team CC: Emese Revfy CC: Brad Spengler Signed-off-by: Greg Kroah-Hartman

disabling oplocks/leases via module parm enable_oplocks broken for SMB3

2015-10-22T21:49:24+00:00

commit e0ddde9d44e37fbc21ce893553094ecf1a633ab5 upstream. leases (oplocks) were always requested for SMB2/SMB3 even when oplocks disabled in the cifs.ko module. Signed-off-by: Steve French Reviewed-by: Chandrika Srinivasan Signed-off-by: Greg Kroah-Hartman

Fix sec=krb5 on smb3 mounts

2015-10-22T21:49:24+00:00

commit ceb1b0b9b4d1089e9f2731a314689ae17784c861 upstream. Kerberos, which is very important for security, was only enabled for CIFS not SMB2/SMB3 mounts (e.g. vers=3.0) Patch based on the information detailed in http://thread.gmane.org/gmane.linux.kernel.cifs/10081/focus=10307 to enable Kerberized SMB2/SMB3 a) SMB2_negotiate: enable/use decode_negTokenInit in SMB2_negotiate b) SMB2_sess_setup: handle Kerberos sectype and replicate Kerberos SMB1 processing done in sess_auth_kerberos Signed-off-by: Noel Power Signed-off-by: Jim McDonough Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

CIFS: fix type confusion in copy offload ioctl

2015-09-29T17:33:25+00:00

commit 4c17a6d56bb0cad3066a714e94f7185a24b40f49 upstream. This might lead to local privilege escalation (code execution as kernel) for systems where the following conditions are met: - CONFIG_CIFS_SMB2 and CONFIG_CIFS_POSIX are enabled - a cifs filesystem is mounted where: - the mount option "vers" was used and set to a value >=2.0 - the attacker has write access to at least one file on the filesystem To attack this, an attacker would have to guess the target_tcon pointer (but guessing wrong doesn't cause a crash, it just returns an error code) and win a narrow race. Signed-off-by: Jann Horn Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

fs: create and use seq_show_option for escaping

2015-09-21T17:10:59+00:00

commit a068acf2ee77693e0bf39d6e07139ba704f461c3 upstream. Many file systems that implement the show_options hook fail to correctly escape their output which could lead to unescaped characters (e.g. new lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This could lead to confusion, spoofed entries (resulting in things like systemd issuing false d-bus "mount" notifications), and who knows what else. This looks like it would only be the root user stepping on themselves, but it's possible weird things could happen in containers or in other situations with delegated mount privileges. Here's an example using overlay with setuid fusermount trusting the contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use of "sudo" is something more sneaky: $ BASE="ovl" $ MNT="$BASE/mnt" $ LOW="$BASE/lower" $ UP="$BASE/upper" $ WORK="$BASE/work/ 0 0 none /proc fuse.pwn user_id=1000" $ mkdir -p "$LOW" "$UP" "$WORK" $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt $ cat /proc/mounts none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0 none /proc fuse.pwn user_id=1000 0 0 $ fusermount -u /proc $ cat /proc/mounts cat: /proc/mounts: No such file or directory This fixes the problem by adding new seq_show_option and seq_show_option_n helpers, and updating the vulnerable show_option handlers to use them as needed. Some, like SELinux, need to be open coded due to unusual existing escape mechanisms. [akpm@linux-foundation.org: add lost chunk, per Kees] [keescook@chromium.org: seq_show_option should be using const parameters] Signed-off-by: Kees Cook Acked-by: Serge Hallyn Acked-by: Jan Kara Acked-by: Paul Moore Cc: J. R. Okajima Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

cifs: Unset CIFS_MOUNT_POSIX_PATHS flag when following dfs mounts

2015-06-29T19:50:22+00:00

In a dfs setup where the client transitions from a server which supports posix paths to a server which doesn't support posix paths, the flag CIFS_MOUNT_POSIX_PATHS is not reset. This leads to the wrong directory separator being used causing smb commands to fail. Consider the following case where a dfs share on a samba server points to a share on windows smb server. # mount -t cifs -o .. //vm140-31/dfsroot/testwin/ # ls -l /mnt; touch /mnt/a total 0 touch: cannot touch ‘/mnt/a’: No such file or directory Signed-off-by: Sachin Prabhu Acked-by: Jeff Layton Signed-off-by: Steve French

Update negotiate protocol for SMB3.11 dialect

2015-06-29T02:15:48+00:00

Send negotiate contexts when SMB3.11 dialect is negotiated (ie the preauth and the encryption contexts) and Initialize SMB3.11 preauth negotiate context salt to random bytes Followon patch will update session setup and tree connect Signed-off-by: Steve French

Add ioctl to set integrity

2015-06-29T02:15:45+00:00

set integrity increases reliability of files stored on SMB3 servers. Add ioctl to allow setting this on files on SMB3 and later mounts. Signed-off-by: Steve French

Add Get/Set Integrity Information structure definitions

2015-06-29T02:15:41+00:00

Signed-off-by: Steve French