1. 04 Jan, 2009 11 commits
  2. 09 Dec, 2008 3 commits
  3. 13 Nov, 2008 4 commits
    • David Howells's avatar
      CRED: Inaugurate COW credentials · d84f4f99
      David Howells authored
      
      
      Inaugurate copy-on-write credentials management.  This uses RCU to manage the
      credentials pointer in the task_struct with respect to accesses by other tasks.
      A process may only modify its own credentials, and so does not need locking to
      access or modify its own credentials.
      
      A mutex (cred_replace_mutex) is added to the task_struct to control the effect
      of PTRACE_ATTACHED on credential calculations, particularly with respect to
      execve().
      
      With this patch, the contents of an active credentials struct may not be
      changed directly; rather a new set of credentials must be prepared, modified
      and committed using something like the following sequence of events:
      
      	struct cred *new = prepare_creds();
      	int ret = blah(new);
      	if (ret < 0) {
      		abort_creds(new);
      		return ret;
      	}
      	return commit_creds(new);
      
      There are some exceptions to this rule: the keyrings pointed to by the active
      credentials may be instantiated - keyrings violate the COW rule as managing
      COW keyrings is tricky, given that it is possible for a task to directly alter
      the keys in a keyring in use by another task.
      
      To help enforce this, various pointers to sets of credentials, such as those in
      the task_struct, are declared const.  The purpose of this is compile-time
      discouragement of altering credentials through those pointers.  Once a set of
      credentials has been made public through one of these pointers, it may not be
      modified, except under special circumstances:
      
        (1) Its reference count may incremented and decremented.
      
        (2) The keyrings to which it points may be modified, but not replaced.
      
      The only safe way to modify anything else is to create a replacement and commit
      using the functions described in Documentation/credentials.txt (which will be
      added by a later patch).
      
      This patch and the preceding patches have been tested with the LTP SELinux
      testsuite.
      
      This patch makes several logical sets of alteration:
      
       (1) execve().
      
           This now prepares and commits credentials in various places in the
           security code rather than altering the current creds directly.
      
       (2) Temporary credential overrides.
      
           do_coredump() and sys_faccessat() now prepare their own credentials and
           temporarily override the ones currently on the acting thread, whilst
           preventing interference from other threads by holding cred_replace_mutex
           on the thread being dumped.
      
           This will be replaced in a future patch by something that hands down the
           credentials directly to the functions being called, rather than altering
           the task's objective credentials.
      
       (3) LSM interface.
      
           A number of functions have been changed, added or removed:
      
           (*) security_capset_check(), ->capset_check()
           (*) security_capset_set(), ->capset_set()
      
           	 Removed in favour of security_capset().
      
           (*) security_capset(), ->capset()
      
           	 New.  This is passed a pointer to the new creds, a pointer to the old
           	 creds and the proposed capability sets.  It should fill in the new
           	 creds or return an error.  All pointers, barring the pointer to the
           	 new creds, are now const.
      
           (*) security_bprm_apply_creds(), ->bprm_apply_creds()
      
           	 Changed; now returns a value, which will cause the process to be
           	 killed if it's an error.
      
           (*) security_task_alloc(), ->task_alloc_security()
      
           	 Removed in favour of security_prepare_creds().
      
           (*) security_cred_free(), ->cred_free()
      
           	 New.  Free security data attached to cred->security.
      
           (*) security_prepare_creds(), ->cred_prepare()
      
           	 New. Duplicate any security data attached to cred->security.
      
           (*) security_commit_creds(), ->cred_commit()
      
           	 New. Apply any security effects for the upcoming installation of new
           	 security by commit_creds().
      
           (*) security_task_post_setuid(), ->task_post_setuid()
      
           	 Removed in favour of security_task_fix_setuid().
      
           (*) security_task_fix_setuid(), ->task_fix_setuid()
      
           	 Fix up the proposed new credentials for setuid().  This is used by
           	 cap_set_fix_setuid() to implicitly adjust capabilities in line with
           	 setuid() changes.  Changes are made to the new credentials, rather
           	 than the task itself as in security_task_post_setuid().
      
           (*) security_task_reparent_to_init(), ->task_reparent_to_init()
      
           	 Removed.  Instead the task being reparented to init is referred
           	 directly to init's credentials.
      
      	 NOTE!  This results in the loss of some state: SELinux's osid no
      	 longer records the sid of the thread that forked it.
      
           (*) security_key_alloc(), ->key_alloc()
           (*) security_key_permission(), ->key_permission()
      
           	 Changed.  These now take cred pointers rather than task pointers to
           	 refer to the security context.
      
       (4) sys_capset().
      
           This has been simplified and uses less locking.  The LSM functions it
           calls have been merged.
      
       (5) reparent_to_kthreadd().
      
           This gives the current thread the same credentials as init by simply using
           commit_thread() to point that way.
      
       (6) __sigqueue_alloc() and switch_uid()
      
           __sigqueue_alloc() can't stop the target task from changing its creds
           beneath it, so this function gets a reference to the currently applicable
           user_struct which it then passes into the sigqueue struct it returns if
           successful.
      
           switch_uid() is now called from commit_creds(), and possibly should be
           folded into that.  commit_creds() should take care of protecting
           __sigqueue_alloc().
      
       (7) [sg]et[ug]id() and co and [sg]et_current_groups.
      
           The set functions now all use prepare_creds(), commit_creds() and
           abort_creds() to build and check a new set of credentials before applying
           it.
      
           security_task_set[ug]id() is called inside the prepared section.  This
           guarantees that nothing else will affect the creds until we've finished.
      
           The calling of set_dumpable() has been moved into commit_creds().
      
           Much of the functionality of set_user() has been moved into
           commit_creds().
      
           The get functions all simply access the data directly.
      
       (8) security_task_prctl() and cap_task_prctl().
      
           security_task_prctl() has been modified to return -ENOSYS if it doesn't
           want to handle a function, or otherwise return the return value directly
           rather than through an argument.
      
           Additionally, cap_task_prctl() now prepares a new set of credentials, even
           if it doesn't end up using it.
      
       (9) Keyrings.
      
           A number of changes have been made to the keyrings code:
      
           (a) switch_uid_keyring(), copy_keys(), exit_keys() and suid_keys() have
           	 all been dropped and built in to the credentials functions directly.
           	 They may want separating out again later.
      
           (b) key_alloc() and search_process_keyrings() now take a cred pointer
           	 rather than a task pointer to specify the security context.
      
           (c) copy_creds() gives a new thread within the same thread group a new
           	 thread keyring if its parent had one, otherwise it discards the thread
           	 keyring.
      
           (d) The authorisation key now points directly to the credentials to extend
           	 the search into rather pointing to the task that carries them.
      
           (e) Installing thread, process or session keyrings causes a new set of
           	 credentials to be created, even though it's not strictly necessary for
           	 process or session keyrings (they're shared).
      
      (10) Usermode helper.
      
           The usermode helper code now carries a cred struct pointer in its
           subprocess_info struct instead of a new session keyring pointer.  This set
           of credentials is derived from init_cred and installed on the new process
           after it has been cloned.
      
           call_usermodehelper_setup() allocates the new credentials and
           call_usermodehelper_freeinfo() discards them if they haven't been used.  A
           special cred function (prepare_usermodeinfo_creds()) is provided
           specifically for call_usermodehelper_setup() to call.
      
           call_usermodehelper_setkeys() adjusts the credentials to sport the
           supplied keyring as the new session keyring.
      
      (11) SELinux.
      
           SELinux has a number of changes, in addition to those to support the LSM
           interface changes mentioned above:
      
           (a) selinux_setprocattr() no longer does its check for whether the
           	 current ptracer can access processes with the new SID inside the lock
           	 that covers getting the ptracer's SID.  Whilst this lock ensures that
           	 the check is done with the ptracer pinned, the result is only valid
           	 until the lock is released, so there's no point doing it inside the
           	 lock.
      
      (12) is_single_threaded().
      
           This function has been extracted from selinux_setprocattr() and put into
           a file of its own in the lib/ directory as join_session_keyring() now
           wants to use it too.
      
           The code in SELinux just checked to see whether a task shared mm_structs
           with other tasks (CLONE_VM), but that isn't good enough.  We really want
           to know if they're part of the same thread group (CLONE_THREAD).
      
      (13) nfsd.
      
           The NFS server daemon now has to use the COW credentials to set the
           credentials it is going to use.  It really needs to pass the credentials
           down to the functions it calls, but it can't do that until other patches
           in this series have been applied.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Acked-by: default avatarJames Morris <jmorris@namei.org>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      d84f4f99
    • David Howells's avatar
      CRED: Use RCU to access another task's creds and to release a task's own creds · c69e8d9c
      David Howells authored
      
      
      Use RCU to access another task's creds and to release a task's own creds.
      This means that it will be possible for the credentials of a task to be
      replaced without another task (a) requiring a full lock to read them, and (b)
      seeing deallocated memory.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Acked-by: default avatarJames Morris <jmorris@namei.org>
      Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      c69e8d9c
    • David Howells's avatar
      CRED: Separate task security context from task_struct · b6dff3ec
      David Howells authored
      
      
      Separate the task security context from task_struct.  At this point, the
      security data is temporarily embedded in the task_struct with two pointers
      pointing to it.
      
      Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
      entry.S via asm-offsets.
      
      With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Acked-by: default avatarJames Morris <jmorris@namei.org>
      Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      b6dff3ec
    • David Howells's avatar
      CRED: Wrap task credential accesses in the core kernel · 76aac0e9
      David Howells authored
      
      
      Wrap access to task credentials so that they can be separated more easily from
      the task_struct during the introduction of COW creds.
      
      Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().
      
      Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
      sense to use RCU directly rather than a convenient wrapper; these will be
      addressed by later patches.
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Reviewed-by: default avatarJames Morris <jmorris@namei.org>
      Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Cc: linux-audit@redhat.com
      Cc: containers@lists.linux-foundation.org
      Cc: linux-mm@kvack.org
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      76aac0e9
  4. 11 Nov, 2008 3 commits
    • Eric Paris's avatar
      When the capset syscall is used it is not possible for audit to record the · e68b75a0
      Eric Paris authored
      
      actual capbilities being added/removed.  This patch adds a new record type
      which emits the target pid and the eff, inh, and perm cap sets.
      
      example output if you audit capset syscalls would be:
      
      type=SYSCALL msg=audit(1225743140.465:76): arch=c000003e syscall=126 success=yes exit=0 a0=17f2014 a1=17f201c a2=80000000 a3=7fff2ab7f060 items=0 ppid=2160 pid=2223 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=1 comm="setcap" exe="/usr/sbin/setcap" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
      type=UNKNOWN[1322] msg=audit(1225743140.465:76): pid=0 cap_pi=ffffffffffffffff cap_pp=ffffffffffffffff cap_pe=ffffffffffffffff
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      e68b75a0
    • Eric Paris's avatar
      Any time fcaps or a setuid app under SECURE_NOROOT is used to result in a · 3fc689e9
      Eric Paris authored
      
      non-zero pE we will crate a new audit record which contains the entire set
      of known information about the executable in question, fP, fI, fE, fversion
      and includes the process's pE, pI, pP.  Before and after the bprm capability
      are applied.  This record type will only be emitted from execve syscalls.
      
      an example of making ping use fcaps instead of setuid:
      
      setcap "cat_net_raw+pe" /bin/ping
      
      type=SYSCALL msg=audit(1225742021.015:236): arch=c000003e syscall=59 success=yes exit=0 a0=1457f30 a1=14606b0 a2=1463940 a3=321b770a70 items=2 ppid=2929 pid=2963 auid=0 uid=500 gid=500 euid=500 suid=500 fsuid=500 egid=500 sgid=500 fsgid=500 tty=pts0 ses=3 comm="ping" exe="/bin/ping" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
      type=UNKNOWN[1321] msg=audit(1225742021.015:236): fver=2 fp=0000000000002000 fi=0000000000000000 fe=1 old_pp=0000000000000000 old_pi=0000000000000000 old_pe=0000000000000000 new_pp=0000000000002000 new_pi=0000000000000000 new_pe=0000000000002000
      type=EXECVE msg=audit(1225742021.015:236): argc=2 a0="ping" a1="127.0.0.1"
      type=CWD msg=audit(1225742021.015:236):  cwd="/home/test"
      type=PATH msg=audit(1225742021.015:236): item=0 name="/bin/ping" inode=49256 dev=fd:00 mode=0100755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ping_exec_t:s0 cap_fp=0000000000002000 cap_fe=1 cap_fver=2
      type=PATH msg=audit(1225742021.015:236): item=1 name=(null) inode=507915 dev=fd:00 mode=0100755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ld_so_t:s0
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      3fc689e9
    • Eric Paris's avatar
      This patch will print cap_permitted and cap_inheritable data in the PATH · 851f7ff5
      Eric Paris authored
      
      records of any file that has file capabilities set.  Files which do not
      have fcaps set will not have different PATH records.
      
      An example audit record if you run:
      setcap "cap_net_admin+pie" /bin/bash
      /bin/bash
      
      type=SYSCALL msg=audit(1225741937.363:230): arch=c000003e syscall=59 success=yes exit=0 a0=2119230 a1=210da30 a2=20ee290 a3=8 items=2 ppid=2149 pid=2923 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=3 comm="ping" exe="/bin/ping" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
      type=EXECVE msg=audit(1225741937.363:230): argc=2 a0="ping" a1="www.google.com"
      type=CWD msg=audit(1225741937.363:230):  cwd="/root"
      type=PATH msg=audit(1225741937.363:230): item=0 name="/bin/ping" inode=49256 dev=fd:00 mode=0104755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ping_exec_t:s0 cap_fp=0000000000002000 cap_fi=0000000000002000 cap_fe=1 cap_fver=2
      type=PATH msg=audit(1225741937.363:230): item=1 name=(null) inode=507915 dev=fd:00 mode=0100755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ld_so_t:s0
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      851f7ff5
  5. 13 Oct, 2008 1 commit
  6. 02 Sep, 2008 1 commit
  7. 04 Aug, 2008 1 commit
  8. 01 Aug, 2008 2 commits
  9. 24 Jul, 2008 1 commit
    • Roland McGrath's avatar
      x86_64 syscall audit fast-path · 86a1c34a
      Roland McGrath authored
      
      
      This adds a fast path for 64-bit syscall entry and exit when
      TIF_SYSCALL_AUDIT is set, but no other kind of syscall tracing.
      This path does not need to save and restore all registers as
      the general case of tracing does.  Avoiding the iret return path
      when syscall audit is enabled helps performance a lot.
      Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
      86a1c34a
  10. 28 Apr, 2008 5 commits
    • Al Viro's avatar
      [PATCH] new predicate - AUDIT_FILETYPE · 8b67dca9
      Al Viro authored
      
      
      Argument is S_IF... | <index>, where index is normally 0 or 1.
      Triggers if chosen element of ctx->names[] is present and the
      mode of object in question matches the upper bits of argument.
      I.e. for things like "is the argument of that chmod a directory",
      etc.
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      8b67dca9
    • Harvey Harrison's avatar
      [PATCH 2/2] audit: fix sparse shadowed variable warnings · 7719e437
      Harvey Harrison authored
      
      
      Use msglen as the identifier.
      kernel/audit.c:724:10: warning: symbol 'len' shadows an earlier one
      kernel/audit.c:575:8: originally declared here
      
      Don't use ino_f to check the inode field at the end of the functions.
      kernel/auditfilter.c:429:22: warning: symbol 'f' shadows an earlier one
      kernel/auditfilter.c:420:21: originally declared here
      kernel/auditfilter.c:542:22: warning: symbol 'f' shadows an earlier one
      kernel/auditfilter.c:529:21: originally declared here
      
      i always used as a counter for a for loop and initialized to zero before
      use.  Eliminate the inner i variables.
      kernel/auditsc.c:1295:8: warning: symbol 'i' shadows an earlier one
      kernel/auditsc.c:1152:6: originally declared here
      kernel/auditsc.c:1320:7: warning: symbol 'i' shadows an earlier one
      kernel/auditsc.c:1152:6: originally declared here
      Signed-off-by: default avatarHarvey Harrison <harvey.harrison@gmail.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      7719e437
    • Harvey Harrison's avatar
      [PATCH 1/2] audit: move extern declarations to audit.h · c782f242
      Harvey Harrison authored
      
      
      Leave audit_sig_{uid|pid|sid} protected by #ifdef CONFIG_AUDITSYSCALL.
      
      Noticed by sparse:
      kernel/audit.c:73:6: warning: symbol 'audit_ever_enabled' was not declared. Should it be static?
      kernel/audit.c:100:8: warning: symbol 'audit_sig_uid' was not declared. Should it be static?
      kernel/audit.c:101:8: warning: symbol 'audit_sig_pid' was not declared. Should it be static?
      kernel/audit.c:102:6: warning: symbol 'audit_sig_sid' was not declared. Should it be static?
      kernel/audit.c:117:23: warning: symbol 'audit_ih' was not declared. Should it be static?
      kernel/auditfilter.c:78:18: warning: symbol 'audit_filter_list' was not declared. Should it be static?
      Signed-off-by: default avatarHarvey Harrison <harvey.harrison@gmail.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      c782f242
    • Eric Paris's avatar
      Audit: standardize string audit interfaces · b556f8ad
      Eric Paris authored
      
      
      This patch standardized the string auditing interfaces.  No userspace
      changes will be visible and this is all just cleanup and consistancy
      work.  We have the following string audit interfaces to use:
      
      void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, size_t len);
      
      void audit_log_n_string(struct audit_buffer *ab, const char *buf, size_t n);
      void audit_log_string(struct audit_buffer *ab, const char *buf);
      
      void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, size_t n);
      void audit_log_untrustedstring(struct audit_buffer *ab, const char *string);
      
      This may be the first step to possibly fixing some of the issues that
      people have with the string output from the kernel audit system.  But we
      still don't have an agreed upon solution to that problem.
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      b556f8ad
    • Eric Paris's avatar
      Audit: end printk with newline · 436c405c
      Eric Paris authored
      
      
      A couple of audit printk statements did not have a newline.
      Signed-off-by: default avatarEric Paris <eparis@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      436c405c
  11. 18 Apr, 2008 3 commits
  12. 01 Mar, 2008 1 commit
  13. 19 Feb, 2008 1 commit
  14. 15 Feb, 2008 2 commits
  15. 01 Feb, 2008 1 commit