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2008-02-05capabilities: introduce per-process capability bounding setSerge E. Hallyn
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: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Andrew 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: "Serge E. Hallyn" <serue@us.ibm.com> Tested-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05VFS/Security: Rework inode_getsecurity and callers to return resulting bufferDavid P. Quigley
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: David P. Quigley <dpquigl@tycho.nsa.gov> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Chris Wright <chrisw@sous-sol.org> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-25security/selinux: constify function pointer tables and fieldsJan Engelhardt
Constify function pointer tables and fields. Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: James Morris <jmorris@namei.org>
2008-01-25security: add a secctx_to_secid() hookDavid Howells
Add a secctx_to_secid() LSM hook to go along with the existing secid_to_secctx() LSM hook. This patch also includes the SELinux implementation for this hook. Signed-off-by: Paul Moore <paul.moore@hp.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
2008-01-25security: remove security_sb_post_mountroot hookH. Peter Anvin
The security_sb_post_mountroot() hook is long-since obsolete, and is fundamentally broken: it is never invoked if someone uses initramfs. This is particularly damaging, because the existence of this hook has been used as motivation for not using initramfs. Stephen Smalley confirmed on 2007-07-19 that this hook was originally used by SELinux but can now be safely removed: http://marc.info/?l=linux-kernel&m=118485683612916&w=2 Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Eric Paris <eparis@parisplace.org> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: James Morris <jmorris@namei.org>
2008-01-25Security: add get, set, and cloning of superblock security informationEric Paris
Adds security_get_sb_mnt_opts, security_set_sb_mnt_opts, and security_clont_sb_mnt_opts to the LSM and to SELinux. This will allow filesystems to directly own and control all of their mount options if they so choose. This interface deals only with option identifiers and strings so it should generic enough for any LSM which may come in the future. Filesystems which pass text mount data around in the kernel (almost all of them) need not currently make use of this interface when dealing with SELinux since it will still parse those strings as it always has. I assume future LSM's would do the same. NFS is the primary FS which does not use text mount data and thus must make use of this interface. An LSM would need to implement these functions only if they had mount time options, such as selinux has context= or fscontext=. If the LSM has no mount time options they could simply not implement and let the dummy ops take care of things. An LSM other than SELinux would need to define new option numbers in security.h and any FS which decides to own there own security options would need to be patched to use this new interface for every possible LSM. This is because it was stated to me very clearly that LSM's should not attempt to understand FS mount data and the burdon to understand security should be in the FS which owns the options. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Stephen D. Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
2007-10-20fix up security_socket_getpeersec_* documentationSerge Hallyn
Update the security_socket_peersec documentation in include/linux/security.h. security_socket_peersec has been split into two functions - _stream and _dgram, with new capabilities. Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Adrian Bunk <bunk@kernel.org>
2007-10-18V3 file capabilities: alter behavior of cap_setpcapAndrew Morgan
The non-filesystem capability meaning of CAP_SETPCAP is that a process, p1, can change the capabilities of another process, p2. This is not the meaning that was intended for this capability at all, and this implementation came about purely because, without filesystem capabilities, there was no way to use capabilities without one process bestowing them on another. Since we now have a filesystem support for capabilities we can fix the implementation of CAP_SETPCAP. The most significant thing about this change is that, with it in effect, no process can set the capabilities of another process. The capabilities of a program are set via the capability convolution rules: pI(post-exec) = pI(pre-exec) pP(post-exec) = (X(aka cap_bset) & fP) | (pI(post-exec) & fI) pE(post-exec) = fE ? pP(post-exec) : 0 at exec() time. As such, the only influence the pre-exec() program can have on the post-exec() program's capabilities are through the pI capability set. The correct implementation for CAP_SETPCAP (and that enabled by this patch) is that it can be used to add extra pI capabilities to the current process - to be picked up by subsequent exec()s when the above convolution rules are applied. Here is how it works: Let's say we have a process, p. It has capability sets, pE, pP and pI. Generally, p, can change the value of its own pI to pI' where (pI' & ~pI) & ~pP = 0. That is, the only new things in pI' that were not present in pI need to be present in pP. The role of CAP_SETPCAP is basically to permit changes to pI beyond the above: if (pE & CAP_SETPCAP) { pI' = anything; /* ie., even (pI' & ~pI) & ~pP != 0 */ } This capability is useful for things like login, which (say, via pam_cap) might want to raise certain inheritable capabilities for use by the children of the logged-in user's shell, but those capabilities are not useful to or needed by the login program itself. One such use might be to limit who can run ping. You set the capabilities of the 'ping' program to be "= cap_net_raw+i", and then only shells that have (pI & CAP_NET_RAW) will be able to run it. Without CAP_SETPCAP implemented as described above, login(pam_cap) would have to also have (pP & CAP_NET_RAW) in order to raise this capability and pass it on through the inheritable set. Signed-off-by: Andrew Morgan <morgan@kernel.org> Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17security/ cleanupsAdrian Bunk
This patch contains the following cleanups that are now possible: - remove the unused security_operations->inode_xattr_getsuffix - remove the no longer used security_operations->unregister_security - remove some no longer required exit code - remove a bunch of no longer used exports Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17Implement file posix capabilitiesSerge E. Hallyn
Implement file posix capabilities. This allows programs to be given a subset of root's powers regardless of who runs them, without having to use setuid and giving the binary all of root's powers. This version works with Kaigai Kohei's userspace tools, found at http://www.kaigai.gr.jp/index.php. For more information on how to use this patch, Chris Friedhoff has posted a nice page at http://www.friedhoff.org/fscaps.html. Changelog: Nov 27: Incorporate fixes from Andrew Morton (security-introduce-file-caps-tweaks and security-introduce-file-caps-warning-fix) Fix Kconfig dependency. Fix change signaling behavior when file caps are not compiled in. Nov 13: Integrate comments from Alexey: Remove CONFIG_ ifdef from capability.h, and use %zd for printing a size_t. Nov 13: Fix endianness warnings by sparse as suggested by Alexey Dobriyan. Nov 09: Address warnings of unused variables at cap_bprm_set_security when file capabilities are disabled, and simultaneously clean up the code a little, by pulling the new code into a helper function. Nov 08: For pointers to required userspace tools and how to use them, see http://www.friedhoff.org/fscaps.html. Nov 07: Fix the calculation of the highest bit checked in check_cap_sanity(). Nov 07: Allow file caps to be enabled without CONFIG_SECURITY, since capabilities are the default. Hook cap_task_setscheduler when !CONFIG_SECURITY. Move capable(TASK_KILL) to end of cap_task_kill to reduce audit messages. Nov 05: Add secondary calls in selinux/hooks.c to task_setioprio and task_setscheduler so that selinux and capabilities with file cap support can be stacked. Sep 05: As Seth Arnold points out, uid checks are out of place for capability code. Sep 01: Define task_setscheduler, task_setioprio, cap_task_kill, and task_setnice to make sure a user cannot affect a process in which they called a program with some fscaps. One remaining question is the note under task_setscheduler: are we ok with CAP_SYS_NICE being sufficient to confine a process to a cpuset? It is a semantic change, as without fsccaps, attach_task doesn't allow CAP_SYS_NICE to override the uid equivalence check. But since it uses security_task_setscheduler, which elsewhere is used where CAP_SYS_NICE can be used to override the uid equivalence check, fixing it might be tough. task_setscheduler note: this also controls cpuset:attach_task. Are we ok with CAP_SYS_NICE being used to confine to a cpuset? task_setioprio task_setnice sys_setpriority uses this (through set_one_prio) for another process. Need same checks as setrlimit Aug 21: Updated secureexec implementation to reflect the fact that euid and uid might be the same and nonzero, but the process might still have elevated caps. Aug 15: Handle endianness of xattrs. Enforce capability version match between kernel and disk. Enforce that no bits beyond the known max capability are set, else return -EPERM. With this extra processing, it may be worth reconsidering doing all the work at bprm_set_security rather than d_instantiate. Aug 10: Always call getxattr at bprm_set_security, rather than caching it at d_instantiate. [morgan@kernel.org: file-caps clean up for linux/capability.h] [bunk@kernel.org: unexport cap_inode_killpriv] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Andrew Morgan <morgan@kernel.org> Signed-off-by: Andrew Morgan <morgan@kernel.org> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17security: Convert LSM into a static interfaceJames Morris
Convert LSM into a static interface, as the ability to unload a security module is not required by in-tree users and potentially complicates the overall security architecture. Needlessly exported LSM symbols have been unexported, to help reduce API abuse. Parameters for the capability and root_plug modules are now specified at boot. The SECURITY_FRAMEWORK_VERSION macro has also been removed. In a nutshell, there is no safe way to unload an LSM. The modular interface is thus unecessary and broken infrastructure. It is used only by out-of-tree modules, which are often binary-only, illegal, abusive of the API and dangerous, e.g. silently re-vectoring SELinux. [akpm@linux-foundation.org: cleanups] [akpm@linux-foundation.org: USB Kconfig fix] [randy.dunlap@oracle.com: fix LSM kernel-doc] Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: "Serge E. Hallyn" <serue@us.ibm.com> Acked-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17SELinux: Improve read/write performanceYuichi Nakamura
It reduces the selinux overhead on read/write by only revalidating permissions in selinux_file_permission if the task or inode labels have changed or the policy has changed since the open-time check. A new LSM hook, security_dentry_open, is added to capture the necessary state at open time to allow this optimization. (see http://marc.info/?l=selinux&m=118972995207740&w=2) Signed-off-by: Yuichi Nakamura<ynakam@hitachisoft.jp> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org>
2007-08-22fix NULL pointer dereference in __vm_enough_memory()Alan Cox
The new exec code inserts an accounted vma into an mm struct which is not current->mm. The existing memory check code has a hard coded assumption that this does not happen as does the security code. As the correct mm is known we pass the mm to the security method and the helper function. A new security test is added for the case where we need to pass the mm and the existing one is modified to pass current->mm to avoid the need to change large amounts of code. (Thanks to Tobias for fixing rejects and testing) Signed-off-by: Alan Cox <alan@redhat.com> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Cc: James Morris <jmorris@redhat.com> Cc: Tobias Diedrich <ranma+kernel@tdiedrich.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-11security: Protection for exploiting null dereference using mmapEric Paris
Add a new security check on mmap operations to see if the user is attempting to mmap to low area of the address space. The amount of space protected is indicated by the new proc tunable /proc/sys/vm/mmap_min_addr and defaults to 0, preserving existing behavior. This patch uses a new SELinux security class "memprotect." Policy already contains a number of allow rules like a_t self:process * (unconfined_t being one of them) which mean that putting this check in the process class (its best current fit) would make it useless as all user processes, which we also want to protect against, would be allowed. By taking the memprotect name of the new class it will also make it possible for us to move some of the other memory protect permissions out of 'process' and into the new class next time we bump the policy version number (which I also think is a good future idea) Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2007-05-09Fix occurrences of "the the "Michael Opdenacker
Signed-off-by: Michael Opdenacker <michael@free-electrons.com> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2007-03-14[PATCH] sanitize security_getprocattr() APIAl Viro
have it return the buffer it had allocated Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12[PATCH] mark struct file_operations const 1Arjan van de Ven
Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11[PATCH] Replace regular code with appropriate calls to container_of()Robert P. J. Day
Replace a small number of expressions with a call to the "container_of()" macro. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Acked-by: Paul Mackerras <paulus@samba.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-02SELinux: Fix SA selection semanticsVenkat Yekkirala
Fix the selection of an SA for an outgoing packet to be at the same context as the originating socket/flow. This eliminates the SELinux policy's ability to use/sendto SAs with contexts other than the socket's. With this patch applied, the SELinux policy will require one or more of the following for a socket to be able to communicate with/without SAs: 1. To enable a socket to communicate without using labeled-IPSec SAs: allow socket_t unlabeled_t:association { sendto recvfrom } 2. To enable a socket to communicate with labeled-IPSec SAs: allow socket_t self:association { sendto }; allow socket_t peer_sa_t:association { recvfrom }; Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: James Morris <jmorris@namei.org>
2006-12-02SELinux: Return correct context for SO_PEERSECVenkat Yekkirala
Fix SO_PEERSEC for tcp sockets to return the security context of the peer (as represented by the SA from the peer) as opposed to the SA used by the local/source socket. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: James Morris <jmorris@namei.org>
2006-12-02SELinux: Various xfrm labeling fixesVenkat Yekkirala
Since the upstreaming of the mlsxfrm modification a few months back, testing has resulted in the identification of the following issues/bugs that are resolved in this patch set. 1. Fix the security context used in the IKE negotiation to be the context of the socket as opposed to the context of the SPD rule. 2. Fix SO_PEERSEC for tcp sockets to return the security context of the peer as opposed to the source. 3. Fix the selection of an SA for an outgoing packet to be at the same context as the originating socket/flow. The following would be the result of applying this patchset: - SO_PEERSEC will now correctly return the peer's context. - IKE deamons will receive the context of the source socket/flow as opposed to the SPD rule's context so that the negotiated SA will be at the same context as the source socket/flow. - The SELinux policy will require one or more of the following for a socket to be able to communicate with/without SAs: 1. To enable a socket to communicate without using labeled-IPSec SAs: allow socket_t unlabeled_t:association { sendto recvfrom } 2. To enable a socket to communicate with labeled-IPSec SAs: allow socket_t self:association { sendto }; allow socket_t peer_sa_t:association { recvfrom }; This Patch: Pass correct security context to IKE for use in negotiation Fix the security context passed to IKE for use in negotiation to be the context of the socket as opposed to the context of the SPD rule so that the SA carries the label of the originating socket/flow. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: James Morris <jmorris@namei.org>
2006-10-11IPsec: correct semantics for SELinux policy matchingVenkat Yekkirala
Currently when an IPSec policy rule doesn't specify a security context, it is assumed to be "unlabeled" by SELinux, and so the IPSec policy rule fails to match to a flow that it would otherwise match to, unless one has explicitly added an SELinux policy rule allowing the flow to "polmatch" to the "unlabeled" IPSec policy rules. In the absence of such an explicitly added SELinux policy rule, the IPSec policy rule fails to match and so the packet(s) flow in clear text without the otherwise applicable xfrm(s) applied. The above SELinux behavior violates the SELinux security notion of "deny by default" which should actually translate to "encrypt by default" in the above case. This was first reported by Evgeniy Polyakov and the way James Morris was seeing the problem was when connecting via IPsec to a confined service on an SELinux box (vsftpd), which did not have the appropriate SELinux policy permissions to send packets via IPsec. With this patch applied, SELinux "polmatching" of flows Vs. IPSec policy rules will only come into play when there's a explicit context specified for the IPSec policy rule (which also means there's corresponding SELinux policy allowing appropriate domains/flows to polmatch to this context). Secondly, when a security module is loaded (in this case, SELinux), the security_xfrm_policy_lookup() hook can return errors other than access denied, such as -EINVAL. We were not handling that correctly, and in fact inverting the return logic and propagating a false "ok" back up to xfrm_lookup(), which then allowed packets to pass as if they were not associated with an xfrm policy. The solution for this is to first ensure that errno values are correctly propagated all the way back up through the various call chains from security_xfrm_policy_lookup(), and handled correctly. Then, flow_cache_lookup() is modified, so that if the policy resolver fails (typically a permission denied via the security module), the flow cache entry is killed rather than having a null policy assigned (which indicates that the packet can pass freely). This also forces any future lookups for the same flow to consult the security module (e.g. SELinux) for current security policy (rather than, say, caching the error on the flow cache entry). This patch: Fix the selinux side of things. This makes sure SELinux polmatching of flow contexts to IPSec policy rules comes into play only when an explicit context is associated with the IPSec policy rule. Also, this no longer defaults the context of a socket policy to the context of the socket since the "no explicit context" case is now handled properly. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: James Morris <jmorris@namei.org>
2006-09-29[PATCH] fs.h: ifdef security fieldsAlexey Dobriyan
[assuming BSD security levels are deleted] The only user of i_security, f_security, s_security fields is SELinux, however, quite a few security modules are trying to get into kernel. So, wrap them under CONFIG_SECURITY. Adding config option for each security field is likely an overkill. Following Stephen Smalley's suggestion, i_security initialization is moved to security_inode_alloc() to not clutter core code with ifdefs and make alloc_inode() codepath tiny little bit smaller and faster. The user of (highly greppable) struct fown_struct::security field is still to be found. I've checked every "fown_struct" and every "f_owner" occurence. Additionally it's removal doesn't break i386 allmodconfig build. struct inode, struct file, struct super_block, struct fown_struct become smaller. P.S. Combined with two reiserfs inode shrinking patches sent to linux-fsdevel, I can finally suck 12 reiserfs inodes into one page. /proc/slabinfo -ext2_inode_cache 388 10 +ext2_inode_cache 384 10 -inode_cache 280 14 +inode_cache 276 14 -proc_inode_cache 296 13 +proc_inode_cache 292 13 -reiser_inode_cache 336 11 +reiser_inode_cache 332 12 <= -shmem_inode_cache 372 10 +shmem_inode_cache 368 10 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-22[NetLabel]: SELinux supportVenkat Yekkirala
Add NetLabel support to the SELinux LSM and modify the socket_post_create() LSM hook to return an error code. The most significant part of this patch is the addition of NetLabel hooks into the following SELinux LSM hooks: * selinux_file_permission() * selinux_socket_sendmsg() * selinux_socket_post_create() * selinux_socket_sock_rcv_skb() * selinux_socket_getpeersec_stream() * selinux_socket_getpeersec_dgram() * selinux_sock_graft() * selinux_inet_conn_request() The basic reasoning behind this patch is that outgoing packets are "NetLabel'd" by labeling their socket and the NetLabel security attributes are checked via the additional hook in selinux_socket_sock_rcv_skb(). NetLabel itself is only a labeling mechanism, similar to filesystem extended attributes, it is up to the SELinux enforcement mechanism to perform the actual access checks. In addition to the changes outlined above this patch also includes some changes to the extended bitmap (ebitmap) and multi-level security (mls) code to import and export SELinux TE/MLS attributes into and out of NetLabel. Signed-off-by: Paul Moore <paul.moore@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22[MLSXFRM]: Auto-labeling of child socketsVenkat Yekkirala
This automatically labels the TCP, Unix stream, and dccp child sockets as well as openreqs to be at the same MLS level as the peer. This will result in the selection of appropriately labeled IPSec Security Associations. This also uses the sock's sid (as opposed to the isec sid) in SELinux enforcement of secmark in rcv_skb and postroute_last hooks. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22[MLSXFRM]: Default labeling of socket specific IPSec policiesVenkat Yekkirala
This defaults the label of socket-specific IPSec policies to be the same as the socket they are set on. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22[MLSXFRM]: Add flow labelingVenkat Yekkirala
This labels the flows that could utilize IPSec xfrms at the points the flows are defined so that IPSec policy and SAs at the right label can be used. The following protos are currently not handled, but they should continue to be able to use single-labeled IPSec like they currently do. ipmr ip_gre ipip igmp sit sctp ip6_tunnel (IPv6 over IPv6 tunnel device) decnet Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22[MLSXFRM]: Flow based matching of xfrm policy and stateVenkat Yekkirala
This implements a seemless mechanism for xfrm policy selection and state matching based on the flow sid. This also includes the necessary SELinux enforcement pieces. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22[MLSXFRM]: Add security sid to sockVenkat Yekkirala
This adds security for IP sockets at the sock level. Security at the sock level is needed to enforce the SELinux security policy for security associations even when a sock is orphaned (such as in the TCP LAST_ACK state). This will also be used to enforce SELinux controls over data arriving at or leaving a child socket while it's still waiting to be accepted. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-02[SECURITY]: Fix build with CONFIG_SECURITY disabled.David S. Miller
include/linux/security.h: In function ‘security_release_secctx’: include/linux/security.h:2757: warning: ‘return’ with a value, in function returning void Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-02[AF_UNIX]: Kernel memory leak fix for af_unix datagram getpeersec patchCatherine Zhang
From: Catherine Zhang <cxzhang@watson.ibm.com> This patch implements a cleaner fix for the memory leak problem of the original unix datagram getpeersec patch. Instead of creating a security context each time a unix datagram is sent, we only create the security context when the receiver requests it. This new design requires modification of the current unix_getsecpeer_dgram LSM hook and addition of two new hooks, namely, secid_to_secctx and release_secctx. The former retrieves the security context and the latter releases it. A hook is required for releasing the security context because it is up to the security module to decide how that's done. In the case of Selinux, it's a simple kfree operation. Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-30[PATCH] SELinux: Add security hook definition for getioprio and insert hooksDavid Quigley
Add a new security hook definition for the sys_ioprio_get operation. At present, the SELinux hook function implementation for this hook is identical to the getscheduler implementation but a separate hook is introduced to allow this check to be specialized in the future if necessary. This patch also creates a helper function get_task_ioprio which handles the access check in addition to retrieving the ioprio value for the task. Signed-off-by: David Quigley <dpquigl@tycho.nsa.gov> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org> Cc: Jens Axboe <axboe@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-30[PATCH] SELinux: extend task_kill hook to handle signals sent by AIO completionDavid Quigley
This patch extends the security_task_kill hook to handle signals sent by AIO completion. In this case, the secid of the task responsible for the signal needs to be obtained and saved earlier, so a security_task_getsecid() hook is added, and then this saved value is passed subsequently to the extended task_kill hook for use in checking. Signed-off-by: David Quigley <dpquigl@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-29[NETLINK]: Encapsulate eff_cap usage within security framework.Darrel Goeddel
This patch encapsulates the usage of eff_cap (in netlink_skb_params) within the security framework by extending security_netlink_recv to include a required capability parameter and converting all direct usage of eff_caps outside of the lsm modules to use the interface. It also updates the SELinux implementation of the security_netlink_send and security_netlink_recv hooks to take advantage of the sid in the netlink_skb_params struct. This also enables SELinux to perform auditing of netlink capability checks. Please apply, for 2.6.18 if possible. Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com> Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-26[PATCH] keys: sort out key quota systemDavid Howells
Add the ability for key creation to overrun the user's quota in some circumstances - notably when a session keyring is created and assigned to a process that didn't previously have one. This means it's still possible to log in, should PAM require the creation of a new session keyring, and fix an overburdened key quota. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] SELinux: add task_movememory hookDavid Quigley
This patch adds new security hook, task_movememory, to be called when memory owened by a task is to be moved (e.g. when migrating pages to a this hook is identical to the setscheduler implementation, but a separate hook introduced to allow this check to be specialized in the future if necessary. Since the last posting, the hook has been renamed following feedback from Christoph Lameter. Signed-off-by: David Quigley <dpquigl@tycho.nsa.gov> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org> Cc: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@muc.de> Acked-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] lsm: add task_setioprio hookJames Morris
Implement an LSM hook for setting a task's IO priority, similar to the hook for setting a tasks's nice value. A previous version of this LSM hook was included in an older version of multiadm by Jan Engelhardt, although I don't recall it being submitted upstream. Also included is the corresponding SELinux hook, which re-uses the setsched permission in the proccess class. Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Jens Axboe <axboe@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23[PATCH] VFS: Permit filesystem to perform statfs with a known root dentryDavid Howells
Give the statfs superblock operation a dentry pointer rather than a superblock pointer. This complements the get_sb() patch. That reduced the significance of sb->s_root, allowing NFS to place a fake root there. However, NFS does require a dentry to use as a target for the statfs operation. This permits the root in the vfsmount to be used instead. linux/mount.h has been added where necessary to make allyesconfig build successfully. Interest has also been expressed for use with the FUSE and XFS filesystems. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-22[PATCH] selinux: add hooks for key subsystemMichael LeMay
Introduce SELinux hooks to support the access key retention subsystem within the kernel. Incorporate new flask headers from a modified version of the SELinux reference policy, with support for the new security class representing retained keys. Extend the "key_alloc" security hook with a task parameter representing the intended ownership context for the key being allocated. Attach security information to root's default keyrings within the SELinux initialization routine. Has passed David's testsuite. Signed-off-by: Michael LeMay <mdlemay@epoch.ncsc.mil> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-17[NET]: Fix warnings after LSM-IPSEC changes.David S. Miller
Assignment used as truth value in xfrm_del_sa() and xfrm_get_policy(). Wrong argument type declared for security_xfrm_state_delete() when SELINUX is disabled. Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17[LSM-IPsec]: SELinux AuthorizeCatherine Zhang
This patch contains a fix for the previous patch that adds security contexts to IPsec policies and security associations. In the previous patch, no authorization (besides the check for write permissions to SAD and SPD) is required to delete IPsec policies and security assocations with security contexts. Thus a user authorized to change SAD and SPD can bypass the IPsec policy authorization by simply deleteing policies with security contexts. To fix this security hole, an additional authorization check is added for removing security policies and security associations with security contexts. Note that if no security context is supplied on add or present on policy to be deleted, the SELinux module allows the change unconditionally. The hook is called on deletion when no context is present, which we may want to change. At present, I left it up to the module. LSM changes: The patch adds two new LSM hooks: xfrm_policy_delete and xfrm_state_delete. The new hooks are necessary to authorize deletion of IPsec policies that have security contexts. The existing hooks xfrm_policy_free and xfrm_state_free lack the context to do the authorization, so I decided to split authorization of deletion and memory management of security data, as is typical in the LSM interface. Use: The new delete hooks are checked when xfrm_policy or xfrm_state are deleted by either the xfrm_user interface (xfrm_get_policy, xfrm_del_sa) or the pfkey interface (pfkey_spddelete, pfkey_delete). SELinux changes: The new policy_delete and state_delete functions are added. Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com> Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-01[PATCH] change lspp ipc auditingSteve Grubb
Hi, The patch below converts IPC auditing to collect sid's and convert to context string only if it needs to output an audit record. This patch depends on the inode audit change patch already being applied. Signed-off-by: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-03-25Merge branch 'audit.b3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current * 'audit.b3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current: (22 commits) [PATCH] fix audit_init failure path [PATCH] EXPORT_SYMBOL patch for audit_log, audit_log_start, audit_log_end and audit_format [PATCH] sem2mutex: audit_netlink_sem [PATCH] simplify audit_free() locking [PATCH] Fix audit operators [PATCH] promiscuous mode [PATCH] Add tty to syscall audit records [PATCH] add/remove rule update [PATCH] audit string fields interface + consumer [PATCH] SE Linux audit events [PATCH] Minor cosmetic cleanups to the code moved into auditfilter.c [PATCH] Fix audit record filtering with !CONFIG_AUDITSYSCALL [PATCH] Fix IA64 success/failure indication in syscall auditing. [PATCH] Miscellaneous bug and warning fixes [PATCH] Capture selinux subject/object context information. [PATCH] Exclude messages by message type [PATCH] Collect more inode information during syscall processing. [PATCH] Pass dentry, not just name, in fsnotify creation hooks. [PATCH] Define new range of userspace messages. [PATCH] Filter rule comparators ... Fixed trivial conflict in security/selinux/hooks.c
2006-03-25[PATCH] refactor capable() to one implementation, add __capable() helperChris Wright
Move capable() to kernel/capability.c and eliminate duplicate implementations. Add __capable() function which can be used to check for capabiilty of any process. Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-20[SECURITY]: TCP/UDP getpeersecCatherine Zhang
This patch implements an application of the LSM-IPSec networking controls whereby an application can determine the label of the security association its TCP or UDP sockets are currently connected to via getsockopt and the auxiliary data mechanism of recvmsg. Patch purpose: This patch enables a security-aware application to retrieve the security context of an IPSec security association a particular TCP or UDP socket is using. The application can then use this security context to determine the security context for processing on behalf of the peer at the other end of this connection. In the case of UDP, the security context is for each individual packet. An example application is the inetd daemon, which could be modified to start daemons running at security contexts dependent on the remote client. Patch design approach: - Design for TCP The patch enables the SELinux LSM to set the peer security context for a socket based on the security context of the IPSec security association. The application may retrieve this context using getsockopt. When called, the kernel determines if the socket is a connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry cache on the socket to retrieve the security associations. If a security association has a security context, the context string is returned, as for UNIX domain sockets. - Design for UDP Unlike TCP, UDP is connectionless. This requires a somewhat different API to retrieve the peer security context. With TCP, the peer security context stays the same throughout the connection, thus it can be retrieved at any time between when the connection is established and when it is torn down. With UDP, each read/write can have different peer and thus the security context might change every time. As a result the security context retrieval must be done TOGETHER with the packet retrieval. The solution is to build upon the existing Unix domain socket API for retrieving user credentials. Linux offers the API for obtaining user credentials via ancillary messages (i.e., out of band/control messages that are bundled together with a normal message). Patch implementation details: - Implementation for TCP The security context can be retrieved by applications using getsockopt with the existing SO_PEERSEC flag. As an example (ignoring error checking): getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen); printf("Socket peer context is: %s\n", optbuf); The SELinux function, selinux_socket_getpeersec, is extended to check for labeled security associations for connected (TCP_ESTABLISHED == sk->sk_state) TCP sockets only. If so, the socket has a dst_cache of struct dst_entry values that may refer to security associations. If these have security associations with security contexts, the security context is returned. getsockopt returns a buffer that contains a security context string or the buffer is unmodified. - Implementation for UDP To retrieve the security context, the application first indicates to the kernel such desire by setting the IP_PASSSEC option via getsockopt. Then the application retrieves the security context using the auxiliary data mechanism. An example server application for UDP should look like this: toggle = 1; toggle_len = sizeof(toggle); setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len); recvmsg(sockfd, &msg_hdr, 0); if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) { cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr); if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) && cmsg_hdr->cmsg_level == SOL_IP && cmsg_hdr->cmsg_type == SCM_SECURITY) { memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext)); } } ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow a server socket to receive security context of the peer. A new ancillary message type SCM_SECURITY. When the packet is received we get the security context from the sec_path pointer which is contained in the sk_buff, and copy it to the ancillary message space. An additional LSM hook, selinux_socket_getpeersec_udp, is defined to retrieve the security context from the SELinux space. The existing function, selinux_socket_getpeersec does not suit our purpose, because the security context is copied directly to user space, rather than to kernel space. Testing: We have tested the patch by setting up TCP and UDP connections between applications on two machines using the IPSec policies that result in labeled security associations being built. For TCP, we can then extract the peer security context using getsockopt on either end. For UDP, the receiving end can retrieve the security context using the auxiliary data mechanism of recvmsg. Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20[PATCH] Miscellaneous bug and warning fixesDustin Kirkland
This patch fixes a couple of bugs revealed in new features recently added to -mm1: * fixes warnings due to inconsistent use of const struct inode *inode * fixes bug that prevent a kernel from booting with audit on, and SELinux off due to a missing function in security/dummy.c * fixes a bug that throws spurious audit_panic() messages due to a missing return just before an error_path label * some reasonable house cleaning in audit_ipc_context(), audit_inode_context(), and audit_log_task_context() Signed-off-by: Dustin Kirkland <dustin.kirkland@us.ibm.com> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-03-20[PATCH] Capture selinux subject/object context information.Dustin Kirkland
This patch extends existing audit records with subject/object context information. Audit records associated with filesystem inodes, ipc, and tasks now contain SELinux label information in the field "subj" if the item is performing the action, or in "obj" if the item is the receiver of an action. These labels are collected via hooks in SELinux and appended to the appropriate record in the audit code. This additional information is required for Common Criteria Labeled Security Protection Profile (LSPP). [AV: fixed kmalloc flags use] [folded leak fixes] [folded cleanup from akpm (kfree(NULL)] [folded audit_inode_context() leak fix] [folded akpm's fix for audit_ipc_perm() definition in case of !CONFIG_AUDIT] Signed-off-by: Dustin Kirkland <dustin.kirkland@us.ibm.com> Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-02-03[PATCH] SELinux: fix size-128 slab leakStephen Smalley
Remove private inode tests from security_inode_alloc and security_inode_free, as we otherwise end up leaking inode security structures for private inodes. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01[PATCH] tpm_bios: needs more securityfs_ functionsRandy Dunlap
tpm_bios.c needs securityfs_xyz() functions. Does include/linux/security.h need stubs for these, or should char/tpm/Makefile just be modified to say: ifdef CONFIG_ACPI ifdef CONFIG_SECURITY obj-$(CONFIG_TCG_TPM) += tpm_bios.o endif endif drivers/char/tpm/tpm_bios.c:494: warning: implicit declaration of function 'securityfs_create_dir' drivers/char/tpm/tpm_bios.c:494: warning: assignment makes pointer from integer without a cast drivers/char/tpm/tpm_bios.c:499: warning: implicit declaration of function 'securityfs_create_file' drivers/char/tpm/tpm_bios.c:501: warning: assignment makes pointer from integer without a cast drivers/char/tpm/tpm_bios.c:508: warning: assignment makes pointer from integer without a cast drivers/char/tpm/tpm_bios.c:523: warning: implicit declaration of function 'securityfs_remove' *** Warning: "securityfs_create_file" [drivers/char/tpm/tpm_bios.ko] undefined! *** Warning: "securityfs_create_dir" [drivers/char/tpm/tpm_bios.ko] undefined! *** Warning: "securityfs_remove" [drivers/char/tpm/tpm_bios.ko] undefined! There are also some gcc and sparse warnings that could be fixed. (see http://www.xenotime.net/linux/doc/build-tpm.out) Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Greg KH <greg@kroah.com> Cc: Kylene Jo Hall <kjhall@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-03[LSM-IPSec]: Security association restriction.Trent Jaeger
This patch series implements per packet access control via the extension of the Linux Security Modules (LSM) interface by hooks in the XFRM and pfkey subsystems that leverage IPSec security associations to label packets. Extensions to the SELinux LSM are included that leverage the patch for this purpose. This patch implements the changes necessary to the XFRM subsystem, pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a socket to use only authorized security associations (or no security association) to send/receive network packets. Patch purpose: The patch is designed to enable access control per packets based on the strongly authenticated IPSec security association. Such access controls augment the existing ones based on network interface and IP address. The former are very coarse-grained, and the latter can be spoofed. By using IPSec, the system can control access to remote hosts based on cryptographic keys generated using the IPSec mechanism. This enables access control on a per-machine basis or per-application if the remote machine is running the same mechanism and trusted to enforce the access control policy. Patch design approach: The overall approach is that policy (xfrm_policy) entries set by user-level programs (e.g., setkey for ipsec-tools) are extended with a security context that is used at policy selection time in the XFRM subsystem to restrict the sockets that can send/receive packets via security associations (xfrm_states) that are built from those policies. A presentation available at www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf from the SELinux symposium describes the overall approach. Patch implementation details: On output, the policy retrieved (via xfrm_policy_lookup or xfrm_sk_policy_lookup) must be authorized for the security context of the socket and the same security context is required for resultant security association (retrieved or negotiated via racoon in ipsec-tools). This is enforced in xfrm_state_find. On input, the policy retrieved must also be authorized for the socket (at __xfrm_policy_check), and the security context of the policy must also match the security association being used. The patch has virtually no impact on packets that do not use IPSec. The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as before. Also, if IPSec is used without security contexts, the impact is minimal. The LSM must allow such policies to be selected for the combination of socket and remote machine, but subsequent IPSec processing proceeds as in the original case. Testing: The pfkey interface is tested using the ipsec-tools. ipsec-tools have been modified (a separate ipsec-tools patch is available for version 0.5) that supports assignment of xfrm_policy entries and security associations with security contexts via setkey and the negotiation using the security contexts via racoon. The xfrm_user interface is tested via ad hoc programs that set security contexts. These programs are also available from me, and contain programs for setting, getting, and deleting policy for testing this interface. Testing of sa functions was done by tracing kernel behavior. Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>