aboutsummaryrefslogtreecommitdiffstats
path: root/security/smack/smack_access.c
Commit message (Collapse)AuthorAge
* Fix common misspellingsLucas De Marchi2011-03-31
| | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* Subject: [PATCH] Smack: mmap controls for library containmentCasey Schaufler2011-01-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the embedded world there are often situations where libraries are updated from a variety of sources, for a variety of reasons, and with any number of security characteristics. These differences might include privilege required for a given library provided interface to function properly, as occurs from time to time in graphics libraries. There are also cases where it is important to limit use of libraries based on the provider of the library and the security aware application may make choices based on that criteria. These issues are addressed by providing an additional Smack label that may optionally be assigned to an object, the SMACK64MMAP attribute. An mmap operation is allowed if there is no such attribute. If there is a SMACK64MMAP attribute the mmap is permitted only if a subject with that label has all of the access permitted a subject with the current task label. Security aware applications may from time to time wish to reduce their "privilege" to avoid accidental use of privilege. One case where this arises is the environment in which multiple sources provide libraries to perform the same functions. An application may know that it should eschew services made available from a particular vendor, or of a particular version. In support of this a secondary list of Smack rules has been added that is local to the task. This list is consulted only in the case where the global list has approved access. It can only further restrict access. Unlike the global last, if no entry is found on the local list access is granted. An application can add entries to its own list by writing to /smack/load-self. The changes appear large as they involve refactoring the list handling to accomodate there being more than one rule list. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
* Smack: Transmute labels on specified directoriesJarkko Sakkinen2010-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a situation where Smack access rules allow processes with multiple labels to write to a directory it is easy to get into a situation where the directory gets cluttered with files that the owner can't deal with because while they could be written to the directory a process at the label of the directory can't write them. This is generally the desired behavior, but when it isn't it is a real issue. This patch introduces a new attribute SMACK64TRANSMUTE that instructs Smack to create the file with the label of the directory under certain circumstances. A new access mode, "t" for transmute, is made available to Smack access rules, which are expanded from "rwxa" to "rwxat". If a file is created in a directory marked as transmutable and if access was granted to perform the operation by a rule that included the transmute mode, then the file gets the Smack label of the directory instead of the Smack label of the creating process. Note that this is equivalent to creating an empty file at the label of the directory and then having the other process write to it. The transmute scheme requires that both the access rule allows transmutation and that the directory be explicitly marked. Signed-off-by: Jarkko Sakkinen <ext-jarkko.2.sakkinen@nokia.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
* This patch adds a new security attribute to Smack calledCasey Schaufler2010-12-02
| | | | | | | | | | | | | | | | SMACK64EXEC. It defines label that is used while task is running. Exception: in smack_task_wait() child task is checked for write access to parent task using label inherited from the task that forked it. Fixed issues from previous submit: - SMACK64EXEC was not read when SMACK64 was not set. - inode security blob was not updated after setting SMACK64EXEC - inode security blob was not updated when removing SMACK64EXEC
* include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo2010-03-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* security: Make lsm_priv union in lsm_audit.h anonymousThomas Liu2009-07-09
| | | | | | | | | Made the lsm_priv union in include/linux/lsm_audit.h anonymous. Signed-off-by: Thomas Liu <tliu@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
* Move variable function in lsm_audit.h into SMACK private spaceThomas Liu2009-07-09
| | | | | | | | | | | | | Moved variable function in include/linux/lsm_audit.h into the smack_audit_data struct since it is never used outside of it. Also removed setting of function in the COMMON_AUDIT_DATA_INIT macro because that variable is now private to SMACK. Signed-off-by: Thomas Liu <tliu@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> I-dont-see-any-problems-with-it: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <jmorris@namei.org>
* smack: implement logging V3Etienne Basset2009-04-13
| | | | | | | | | | | | | | | | | the following patch, add logging of Smack security decisions. This is of course very useful to understand what your current smack policy does. As suggested by Casey, it also now forbids labels with ', " or \ It introduces a '/smack/logging' switch : 0: no logging 1: log denied (default) 2: log accepted 3: log denied&accepted Signed-off-by: Etienne Basset <etienne.basset@numericable.fr> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
* smack: Add a new '-CIPSO' option to the network address label configurationEtienne Basset2009-03-28
| | | | | | | | | | | | | This patch adds a new special option '-CIPSO' to the Smack subsystem. When used in the netlabel list, it means "use CIPSO networking". A use case is when your local network speaks CIPSO and you want also to connect to the unlabeled Internet. This patch also add some documentation describing that. The patch also corrects an oops when setting a '' SMACK64 xattr to a file. Signed-off-by: Etienne Basset <etienne.basset@numericable.fr> Signed-off-by: Paul Moore <paul.moore@hp.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <jmorris@namei.org>
* smack: convert smack to standard linux listsEtienne Basset2009-03-25
| | | | | | | | | | | the following patch (on top of 2.6.29) converts Smack lists to standard linux lists Please review and consider for inclusion in 2.6.30-rc regards, Etienne Signed-off-by: Etienne Basset <etienne.basset@numericable.fr> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
* smack: fix lots of kernel-doc notationRandy Dunlap2009-02-18
| | | | | | | | Fix/add kernel-doc notation and fix typos in security/smack/. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <jmorris@namei.org>
* smack: Add support for unlabeled network hosts and networksCasey Schaufler2008-12-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for unlabeled network hosts and networks. Relies heavily on Paul Moore's netlabel support. Creates a new entry in /smack called netlabel. Writes to /smack/netlabel take the form: A.B.C.D LABEL or A.B.C.D/N LABEL where A.B.C.D is a network address, N is an integer between 0-32, and LABEL is the Smack label to be used. If /N is omitted /32 is assumed. N designates the netmask for the address. Entries are matched by the most specific address/mask pair. 0.0.0.0/0 will match everything, while 192.168.1.117/32 will match exactly one host. A new system label "@", pronounced "web", is defined. Processes can not be assigned the web label. An address assigned the web label can be written to by any process, and packets coming from a web address can be written to any socket. Use of the web label is a violation of any strict MAC policy, but the web label has been requested many times. The nltype entry has been removed from /smack. It did not work right and the netlabel interface can be used to specify that all hosts be treated as unlabeled. CIPSO labels on incoming packets will be honored, even from designated single label hosts. Single label hosts can only be written to by processes with labels that can write to the label of the host. Packets sent to single label hosts will always be unlabeled. Once added a single label designation cannot be removed, however the label may be changed. The behavior of the ambient label remains unchanged. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul.moore@hp.com>
* CRED: Wrap current->cred and a few other accessorsDavid Howells2008-11-13
| | | | | | | | | | Wrap current->cred and a few other accessors to hide their actual implementation. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* CRED: Separate task security context from task_structDavid Howells2008-11-13
| | | | | | | | | | | | | | | | 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: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
* smack: limit privilege by labelCasey Schaufler2008-08-04
| | | | | | | | | | | | | | | | | | | | | | | | | | There have been a number of requests to make the Smack LSM enforce MAC even in the face of privilege, either capability based or superuser based. This is not universally desired, however, so it seems desirable to make it optional. Further, at least one legacy OS implemented a scheme whereby only processes running with one particular label could be exempt from MAC. This patch supports these three cases. If /smack/onlycap is empty (unset or null-string) privilege is enforced in the normal way. If /smack/onlycap contains a label only processes running with that label may be MAC exempt. If the label in /smack/onlycap is the star label ("*") the semantics of the star label combine with the privilege restrictions to prevent any violations of MAC, even in the presence of privilege. Again, this will be independent of the privilege scheme. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: James Morris <jmorris@namei.org>
* Smack: Simplified Mandatory Access Control KernelCasey Schaufler2008-02-05
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: Casey 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>