Skip to content
Snippets Groups Projects
  1. Mar 13, 2008
  2. Mar 05, 2008
    • Eric Paris's avatar
      LSM/SELinux: Interfaces to allow FS to control mount options · e0007529
      Eric Paris authored
      
      Introduce new LSM interfaces to allow an FS to deal with their own mount
      options.  This includes a new string parsing function exported from the
      LSM that an FS can use to get a security data blob and a new security
      data blob.  This is particularly useful for an FS which uses binary
      mount data, like NFS, which does not pass strings into the vfs to be
      handled by the loaded LSM.  Also fix a BUG() in both SELinux and SMACK
      when dealing with binary mount data.  If the binary mount data is less
      than one page the copy_page() in security_sb_copy_data() can cause an
      illegal page fault and boom.  Remove all NFSisms from the SELinux code
      since they were broken by past NFS changes.
      
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Acked-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
      Acked-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      e0007529
  3. Feb 23, 2008
  4. Feb 19, 2008
    • Casey Schaufler's avatar
      Smack: unlabeled outgoing ambient packets · 4bc87e62
      Casey Schaufler authored
      
      Smack uses CIPSO labeling, but allows for unlabeled packets by
      specifying an "ambient" label that is applied to incoming unlabeled
      packets.
      
      Because the other end of the connection may dislike IP options, and ssh
      is one know application that behaves thus, it is prudent to respond in
      kind.
      
      This patch changes the network labeling behavior such that an outgoing
      packet that would be given a CIPSO label that matches the ambient label
      is left unlabeled.  An "unlbl" domain is added and the netlabel
      defaulting mechanism invoked rather than assuming that everything is
      CIPSO.  Locking has been added around changes to the ambient label as
      the mechanisms used to do so are more involved.
      
      Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
      Acked-by: default avatarPaul Moore <paul.moore@hp.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4bc87e62
  5. Feb 14, 2008
  6. Feb 13, 2008
  7. Feb 11, 2008
  8. Feb 07, 2008
  9. Feb 06, 2008
  10. Feb 05, 2008
    • Casey Schaufler's avatar
      Smack: Simplified Mandatory Access Control Kernel · e114e473
      Casey Schaufler authored
      Smack is the Simplified Mandatory Access Control Kernel.
      
      Smack implements mandatory access control (MAC) using labels
      attached to tasks and data containers, including files, SVIPC,
      and other tasks. Smack is a kernel based scheme that requires
      an absolute minimum of application support and a very small
      amount of configuration data.
      
      Smack uses extended attributes and
      provides a set of general mount options, borrowing technics used
      elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides
      a pseudo-filesystem smackfs that is used for manipulation of
      system Smack attributes.
      
      The patch, patches for ls and sshd, a README, a startup script,
      and x86 binaries for ls and sshd are also available on
      
          http://www.schaufler-ca.com
      
      
      
      Development has been done using Fedora Core 7 in a virtual machine
      environment and on an old Sony laptop.
      
      Smack provides mandatory access controls based on the label attached
      to a task and the label attached to the object it is attempting to
      access. Smack labels are deliberately short (1-23 characters) text
      strings. Single character labels using special characters are reserved
      for system use. The only operation applied to Smack labels is equality
      comparison. No wildcards or expressions, regular or otherwise, are
      used. Smack labels are composed of printable characters and may not
      include "/".
      
      A file always gets the Smack label of the task that created it.
      
      Smack defines and uses these labels:
      
          "*" - pronounced "star"
          "_" - pronounced "floor"
          "^" - pronounced "hat"
          "?" - pronounced "huh"
      
      The access rules enforced by Smack are, in order:
      
      1. Any access requested by a task labeled "*" is denied.
      2. A read or execute access requested by a task labeled "^"
         is permitted.
      3. A read or execute access requested on an object labeled "_"
         is permitted.
      4. Any access requested on an object labeled "*" is permitted.
      5. Any access requested by a task on an object with the same
         label is permitted.
      6. Any access requested that is explicitly defined in the loaded
         rule set is permitted.
      7. Any other access is denied.
      
      Rules may be explicitly defined by writing subject,object,access
      triples to /smack/load.
      
      Smack rule sets can be easily defined that describe Bell&LaPadula
      sensitivity, Biba integrity, and a variety of interesting
      configurations. Smack rule sets can be modified on the fly to
      accommodate changes in the operating environment or even the time
      of day.
      
      Some practical use cases:
      
      Hierarchical levels. The less common of the two usual uses
      for MLS systems is to define hierarchical levels, often
      unclassified, confidential, secret, and so on. To set up smack
      to support this, these rules could be defined:
      
         C        Unclass rx
         S        C       rx
         S        Unclass rx
         TS       S       rx
         TS       C       rx
         TS       Unclass rx
      
      A TS process can read S, C, and Unclass data, but cannot write it.
      An S process can read C and Unclass. Note that specifying that
      TS can read S and S can read C does not imply TS can read C, it
      has to be explicitly stated.
      
      Non-hierarchical categories. This is the more common of the
      usual uses for an MLS system. Since the default rule is that a
      subject cannot access an object with a different label no
      access rules are required to implement compartmentalization.
      
      A case that the Bell & LaPadula policy does not allow is demonstrated
      with this Smack access rule:
      
      A case that Bell&LaPadula does not allow that Smack does:
      
          ESPN    ABC   r
          ABC     ESPN  r
      
      On my portable video device I have two applications, one that
      shows ABC programming and the other ESPN programming. ESPN wants
      to show me sport stories that show up as news, and ABC will
      only provide minimal information about a sports story if ESPN
      is covering it. Each side can look at the other's info, neither
      can change the other. Neither can see what FOX is up to, which
      is just as well all things considered.
      
      Another case that I especially like:
      
          SatData Guard   w
          Guard   Publish w
      
      A program running with the Guard label opens a UDP socket and
      accepts messages sent by a program running with a SatData label.
      The Guard program inspects the message to ensure it is wholesome
      and if it is sends it to a program running with the Publish label.
      This program then puts the information passed in an appropriate
      place. Note that the Guard program cannot write to a Publish
      file system object because file system semanitic require read as
      well as write.
      
      The four cases (categories, levels, mutual read, guardbox) here
      are all quite real, and problems I've been asked to solve over
      the years. The first two are easy to do with traditonal MLS systems
      while the last two you can't without invoking privilege, at least
      for a while.
      
      Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
      Cc: Joshua Brindle <method@manicmethod.com>
      Cc: Paul Moore <paul.moore@hp.com>
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Cc: Chris Wright <chrisw@sous-sol.org>
      Cc: James Morris <jmorris@namei.org>
      Cc: "Ahmed S. Darwish" <darwish.07@gmail.com>
      Cc: Andrew G. Morgan <morgan@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e114e473
    • Serge E. Hallyn's avatar
      capabilities: introduce per-process capability bounding set · 3b7391de
      Serge E. Hallyn authored
      
      The capability bounding set is a set beyond which capabilities cannot grow.
       Currently cap_bset is per-system.  It can be manipulated through sysctl,
      but only init can add capabilities.  Root can remove capabilities.  By
      default it includes all caps except CAP_SETPCAP.
      
      This patch makes the bounding set per-process when file capabilities are
      enabled.  It is inherited at fork from parent.  Noone can add elements,
      CAP_SETPCAP is required to remove them.
      
      One example use of this is to start a safer container.  For instance, until
      device namespaces or per-container device whitelists are introduced, it is
      best to take CAP_MKNOD away from a container.
      
      The bounding set will not affect pP and pE immediately.  It will only
      affect pP' and pE' after subsequent exec()s.  It also does not affect pI,
      and exec() does not constrain pI'.  So to really start a shell with no way
      of regain CAP_MKNOD, you would do
      
      	prctl(PR_CAPBSET_DROP, CAP_MKNOD);
      	cap_t cap = cap_get_proc();
      	cap_value_t caparray[1];
      	caparray[0] = CAP_MKNOD;
      	cap_set_flag(cap, CAP_INHERITABLE, 1, caparray, CAP_DROP);
      	cap_set_proc(cap);
      	cap_free(cap);
      
      The following test program will get and set the bounding
      set (but not pI).  For instance
      
      	./bset get
      		(lists capabilities in bset)
      	./bset drop cap_net_raw
      		(starts shell with new bset)
      		(use capset, setuid binary, or binary with
      		file capabilities to try to increase caps)
      
      ************************************************************
      cap_bound.c
      ************************************************************
       #include <sys/prctl.h>
       #include <linux/capability.h>
       #include <sys/types.h>
       #include <unistd.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>
      
       #ifndef PR_CAPBSET_READ
       #define PR_CAPBSET_READ 23
       #endif
      
       #ifndef PR_CAPBSET_DROP
       #define PR_CAPBSET_DROP 24
       #endif
      
      int usage(char *me)
      {
      	printf("Usage: %s get\n", me);
      	printf("       %s drop <capability>\n", me);
      	return 1;
      }
      
       #define numcaps 32
      char *captable[numcaps] = {
      	"cap_chown",
      	"cap_dac_override",
      	"cap_dac_read_search",
      	"cap_fowner",
      	"cap_fsetid",
      	"cap_kill",
      	"cap_setgid",
      	"cap_setuid",
      	"cap_setpcap",
      	"cap_linux_immutable",
      	"cap_net_bind_service",
      	"cap_net_broadcast",
      	"cap_net_admin",
      	"cap_net_raw",
      	"cap_ipc_lock",
      	"cap_ipc_owner",
      	"cap_sys_module",
      	"cap_sys_rawio",
      	"cap_sys_chroot",
      	"cap_sys_ptrace",
      	"cap_sys_pacct",
      	"cap_sys_admin",
      	"cap_sys_boot",
      	"cap_sys_nice",
      	"cap_sys_resource",
      	"cap_sys_time",
      	"cap_sys_tty_config",
      	"cap_mknod",
      	"cap_lease",
      	"cap_audit_write",
      	"cap_audit_control",
      	"cap_setfcap"
      };
      
      int getbcap(void)
      {
      	int comma=0;
      	unsigned long i;
      	int ret;
      
      	printf("i know of %d capabilities\n", numcaps);
      	printf("capability bounding set:");
      	for (i=0; i<numcaps; i++) {
      		ret = prctl(PR_CAPBSET_READ, i);
      		if (ret < 0)
      			perror("prctl");
      		else if (ret==1)
      			printf("%s%s", (comma++) ? ", " : " ", captable[i]);
      	}
      	printf("\n");
      	return 0;
      }
      
      int capdrop(char *str)
      {
      	unsigned long i;
      
      	int found=0;
      	for (i=0; i<numcaps; i++) {
      		if (strcmp(captable[i], str) == 0) {
      			found=1;
      			break;
      		}
      	}
      	if (!found)
      		return 1;
      	if (prctl(PR_CAPBSET_DROP, i)) {
      		perror("prctl");
      		return 1;
      	}
      	return 0;
      }
      
      int main(int argc, char *argv[])
      {
      	if (argc<2)
      		return usage(argv[0]);
      	if (strcmp(argv[1], "get")==0)
      		return getbcap();
      	if (strcmp(argv[1], "drop")!=0 || argc<3)
      		return usage(argv[0]);
      	if (capdrop(argv[2])) {
      		printf("unknown capability\n");
      		return 1;
      	}
      	return execl("/bin/bash", "/bin/bash", NULL);
      }
      ************************************************************
      
      [serue@us.ibm.com: fix typo]
      Signed-off-by: default avatarSerge E. Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarAndrew G. Morgan <morgan@kernel.org>
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Cc: James Morris <jmorris@namei.org>
      Cc: Chris Wright <chrisw@sous-sol.org>
      Cc: Casey Schaufler <casey@schaufler-ca.com>a
      Signed-off-by: default avatar"Serge E. Hallyn" <serue@us.ibm.com>
      Tested-by: default avatarJiri Slaby <jirislaby@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3b7391de
    • Andrew Morgan's avatar
      Add 64-bit capability support to the kernel · e338d263
      Andrew Morgan authored
      The patch supports legacy (32-bit) capability userspace, and where possible
      translates 32-bit capabilities to/from userspace and the VFS to 64-bit
      kernel space capabilities.  If a capability set cannot be compressed into
      32-bits for consumption by user space, the system call fails, with -ERANGE.
      
      FWIW libcap-2.00 supports this change (and earlier capability formats)
      
       http://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/
      
      
      
      [akpm@linux-foundation.org: coding-syle fixes]
      [akpm@linux-foundation.org: use get_task_comm()]
      [ezk@cs.sunysb.edu: build fix]
      [akpm@linux-foundation.org: do not initialise statics to 0 or NULL]
      [akpm@linux-foundation.org: unused var]
      [serue@us.ibm.com: export __cap_ symbols]
      Signed-off-by: default avatarAndrew G. Morgan <morgan@kernel.org>
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Cc: Chris Wright <chrisw@sous-sol.org>
      Cc: James Morris <jmorris@namei.org>
      Cc: Casey Schaufler <casey@schaufler-ca.com>
      Signed-off-by: default avatarErez Zadok <ezk@cs.sunysb.edu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e338d263
    • Andrew Morton's avatar
      revert "capabilities: clean up file capability reading" · 8f6936f4
      Andrew Morton authored
      
      Revert b68680e4 to make way for the next
      patch: "Add 64-bit capability support to the kernel".
      
      We want to keep the vfs_cap_data.data[] structure, using two 'data's for
      64-bit caps (and later three for 96-bit caps), whereas
      b68680e4 had gotten rid of the 'data' struct
      made its members inline.
      
      The 64-bit caps patch keeps the stack abuse fix at get_file_caps(), which was
      the more important part of that patch.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Cc: Serge Hallyn <serue@us.ibm.com>
      Cc: Chris Wright <chrisw@sous-sol.org>
      Cc: James Morris <jmorris@namei.org>
      Cc: Casey Schaufler <casey@schaufler-ca.com>
      Cc: Andrew Morgan <morgan@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8f6936f4
    • David P. Quigley's avatar
      VFS/Security: Rework inode_getsecurity and callers to return resulting buffer · 42492594
      David P. Quigley authored
      
      This patch modifies the interface to inode_getsecurity to have the function
      return a buffer containing the security blob and its length via parameters
      instead of relying on the calling function to give it an appropriately sized
      buffer.
      
      Security blobs obtained with this function should be freed using the
      release_secctx LSM hook.  This alleviates the problem of the caller having to
      guess a length and preallocate a buffer for this function allowing it to be
      used elsewhere for Labeled NFS.
      
      The patch also removed the unused err parameter.  The conversion is similar to
      the one performed by Al Viro for the security_getprocattr hook.
      
      Signed-off-by: default avatarDavid P. Quigley <dpquigl@tycho.nsa.gov>
      Cc: Stephen Smalley <sds@tycho.nsa.gov>
      Cc: Chris Wright <chrisw@sous-sol.org>
      Acked-by: default avatarJames Morris <jmorris@namei.org>
      Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Cc: Casey Schaufler <casey@schaufler-ca.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      42492594
  11. Feb 01, 2008
  12. Jan 31, 2008
  13. Jan 29, 2008
  14. Jan 28, 2008
  15. Jan 25, 2008
  16. Jan 24, 2008
Loading