kernel/linux.git/security/smack, branch v6.12.53

smack: Revert "smackfs: Added check catlen"

2025-05-29T09:02:48+00:00

[ Upstream commit c7fb50cecff9cad19fdac5b37337eae4e42b94c7 ] This reverts commit ccfd889acb06eab10b98deb4b5eef0ec74157ea0 The indicated commit * does not describe the problem that change tries to solve * has programming issues * introduces a bug: forever clears NETLBL_SECATTR_MLS_CAT in (struct smack_known *)skp->smk_netlabel.flags Reverting the commit to reapproach original problem Signed-off-by: Konstantin Andreev Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin

smack: recognize ipv4 CIPSO w/o categories

2025-05-29T09:02:48+00:00

[ Upstream commit a158a937d864d0034fea14913c1f09c6d5f574b8 ] If SMACK label has CIPSO representation w/o categories, e.g.: | # cat /smack/cipso2 | foo 10 | @ 250/2 | ... then SMACK does not recognize such CIPSO in input ipv4 packets and substitues '*' label instead. Audit records may look like | lsm=SMACK fn=smack_socket_sock_rcv_skb action=denied | subject="*" object="_" requested=w pid=0 comm="swapper/1" ... This happens in two steps: 1) security/smack/smackfs.c`smk_set_cipso does not clear NETLBL_SECATTR_MLS_CAT from (struct smack_known *)skp->smk_netlabel.flags on assigning CIPSO w/o categories: | rcu_assign_pointer(skp->smk_netlabel.attr.mls.cat, ncats.attr.mls.cat); | skp->smk_netlabel.attr.mls.lvl = ncats.attr.mls.lvl; 2) security/smack/smack_lsm.c`smack_from_secattr can not match skp->smk_netlabel with input packet's struct netlbl_lsm_secattr *sap because sap->flags have not NETLBL_SECATTR_MLS_CAT (what is correct) but skp->smk_netlabel.flags have (what is incorrect): | if ((sap->flags & NETLBL_SECATTR_MLS_CAT) == 0) { | if ((skp->smk_netlabel.flags & | NETLBL_SECATTR_MLS_CAT) == 0) | found = 1; | break; | } This commit sets/clears NETLBL_SECATTR_MLS_CAT in skp->smk_netlabel.flags according to the presense of CIPSO categories. The update of smk_netlabel is not atomic, so input packets processing still may be incorrect during short time while update proceeds. Signed-off-by: Konstantin Andreev Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin

smack: ipv4/ipv6: tcp/dccp/sctp: fix incorrect child socket label

2025-04-10T12:39:10+00:00

[ Upstream commit 6cce0cc3861337b3ad8d4ac131d6e47efa0954ec ] Since inception [1], SMACK initializes ipv* child socket security for connection-oriented communications (tcp/sctp/dccp) during accept() syscall, in the security_sock_graft() hook: | void smack_sock_graft(struct sock *sk, ...) | { | // only ipv4 and ipv6 are eligible here | // ... | ssp = sk->sk_security; // socket security | ssp->smk_in = skp; // process label: smk_of_current() | ssp->smk_out = skp; // process label: smk_of_current() | } This approach is incorrect for two reasons: A) initialization occurs too late for child socket security: The child socket is created by the kernel once the handshake completes (e.g., for tcp: after receiving ack for syn+ack). Data can legitimately start arriving to the child socket immediately, long before the application calls accept() on the socket. Those data are (currently — were) processed by SMACK using incorrect child socket security attributes. B) Incoming connection requests are handled using the listening socket's security, hence, the child socket must inherit the listening socket's security attributes. smack_sock_graft() initilizes the child socket's security with a process label, as is done for a new socket() But ... the process label is not necessarily the same as the listening socket label. A privileged application may legitimately set other in/out labels for a listening socket. When this happens, SMACK processes incoming packets using incorrect socket security attributes. In [2] Michael Lontke noticed (A) and fixed it in [3] by adding socket initialization into security_sk_clone_security() hook like | void smack_sk_clone_security(struct sock *oldsk, struct sock *newsk) | { | *(struct socket_smack *)newsk->sk_security = | *(struct socket_smack *)oldsk->sk_security; | } This initializes the child socket security with the parent (listening) socket security at the appropriate time. I was forced to revisit this old story because smack_sock_graft() was left in place by [3] and continues overwriting the child socket's labels with the process label, and there might be a reason for this, so I undertook a study. If the process label differs from the listening socket's labels, the following occurs for ipv4: assigning the smk_out is not accompanied by netlbl_sock_setattr, so the outgoing packet's cipso label does not change. So, the only effect of this assignment for interhost communications is a divergence between the program-visible “out” socket label and the cipso network label. For intrahost communications this label, however, becomes visible via secmark netfilter marking, and is checked for access rights by the client, receiving side. Assigning the smk_in affects both interhost and intrahost communications: the server begins to check access rights against an wrong label. Access check against wrong label (smk_in or smk_out), unsurprisingly fails, breaking the connection. The above affects protocols that calls security_sock_graft() during accept(), namely: {tcp,dccp,sctp}/{ipv4,ipv6} One extra security_sock_graft() caller, crypto/af_alg.c`af_alg_accept is not affected, because smack_sock_graft() does nothing for PF_ALG. To reproduce, assign non-default in/out labels to a listening socket, setup rules between these labels and client label, attempt to connect and send some data. Ipv6 specific: ipv6 packets do not convey SMACK labels. To reproduce the issue in interhost communications set opposite labels in /smack/ipv6host on both hosts. Ipv6 intrahost communications do not require tricking, because SMACK labels are conveyed via secmark netfilter marking. So, currently smack_sock_graft() is not useful, but harmful, therefore, I have removed it. This fixes the issue for {tcp,dccp}/{ipv4,ipv6}, but not sctp/{ipv4,ipv6}. Although this change is necessary for sctp+smack to function correctly, it is not sufficient because: sctp/ipv4 does not call security_sk_clone() and sctp/ipv6 ignores SMACK completely. These are separate issues, belong to other subsystem, and should be addressed separately. [1] 2008-02-04, Fixes: e114e473771c ("Smack: Simplified Mandatory Access Control Kernel") [2] Michael Lontke, 2022-08-31, SMACK LSM checks wrong object label during ingress network traffic Link: https://lore.kernel.org/linux-security-module/6324997ce4fc092c5020a4add075257f9c5f6442.camel@elektrobit.com/ [3] 2022-08-31, michael.lontke, commit 4ca165fc6c49 ("SMACK: Add sk_clone_security LSM hook") Signed-off-by: Konstantin Andreev Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin

smack: dont compile ipv6 code unless ipv6 is configured

2025-04-10T12:39:10+00:00

[ Upstream commit bfcf4004bcbce2cb674b4e8dbd31ce0891766bac ] I want to be sure that ipv6-specific code is not compiled in kernel binaries if ipv6 is not configured. [1] was getting rid of "unused variable" warning, but, with that, it also mandated compilation of a handful ipv6- specific functions in ipv4-only kernel configurations: smk_ipv6_localhost, smack_ipv6host_label, smk_ipv6_check. Their compiled bodies are likely to be removed by compiler from the resulting binary, but, to be on the safe side, I remove them from the compiler view. [1] Fixes: 00720f0e7f28 ("smack: avoid unused 'sip' variable warning") Signed-off-by: Konstantin Andreev Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin

Merge tag 'lsm-pr-20240923' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

2024-09-24T17:18:15+00:00

Pull LSM fixes from Paul Moore: - Add a missing security_mmap_file() check to the remap_file_pages() syscall - Properly reference the SELinux and Smack LSM blobs in the security_watch_key() LSM hook - Fix a random IPE selftest crash caused by a missing list terminator in the test * tag 'lsm-pr-20240923' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: ipe: Add missing terminator to list of unit tests selinux,smack: properly reference the LSM blob in security_watch_key() mm: call the security_mmap_file() LSM hook in remap_file_pages()

selinux,smack: properly reference the LSM blob in security_watch_key()

2024-09-19T20:37:01+00:00

Unfortunately when we migrated the lifecycle management of the key LSM blob to the LSM framework we forgot to convert the security_watch_key() callbacks for SELinux and Smack. This patch corrects this by making use of the selinux_key() and smack_key() helper functions respectively. This patch also removes some input checking in the Smack callback as it is no longer needed. Fixes: 5f8d28f6d7d5 ("lsm: infrastructure management of the key security blob") Reported-by: syzbot+044fdf24e96093584232@syzkaller.appspotmail.com Tested-by: syzbot+044fdf24e96093584232@syzkaller.appspotmail.com Reviewed-by: Casey Schaufler Signed-off-by: Paul Moore

Merge tag 'Smack-for-6.12' of https://github.com/cschaufler/smack-next

2024-09-19T11:09:19+00:00

Pull smack updates from Casey Schaufler: "Two patches: one is a simple indentation correction, the other corrects a potentially rcu unsafe pointer assignment" * tag 'Smack-for-6.12' of https://github.com/cschaufler/smack-next: smackfs: Use rcu_assign_pointer() to ensure safe assignment in smk_set_cipso security: smack: Fix indentation in smack_netfilter.c

Merge tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

2024-09-16T16:19:47+00:00

Pull lsm updates from Paul Moore: - Move the LSM framework to static calls This transitions the vast majority of the LSM callbacks into static calls. Those callbacks which haven't been converted were left as-is due to the general ugliness of the changes required to support the static call conversion; we can revisit those callbacks at a future date. - Add the Integrity Policy Enforcement (IPE) LSM This adds a new LSM, Integrity Policy Enforcement (IPE). There is plenty of documentation about IPE in this patches, so I'll refrain from going into too much detail here, but the basic motivation behind IPE is to provide a mechanism such that administrators can restrict execution to only those binaries which come from integrity protected storage, e.g. a dm-verity protected filesystem. You will notice that IPE requires additional LSM hooks in the initramfs, dm-verity, and fs-verity code, with the associated patches carrying ACK/review tags from the associated maintainers. We couldn't find an obvious maintainer for the initramfs code, but the IPE patchset has been widely posted over several years. Both Deven Bowers and Fan Wu have contributed to IPE's development over the past several years, with Fan Wu agreeing to serve as the IPE maintainer moving forward. Once IPE is accepted into your tree, I'll start working with Fan to ensure he has the necessary accounts, keys, etc. so that he can start submitting IPE pull requests to you directly during the next merge window. - Move the lifecycle management of the LSM blobs to the LSM framework Management of the LSM blobs (the LSM state buffers attached to various kernel structs, typically via a void pointer named "security" or similar) has been mixed, some blobs were allocated/managed by individual LSMs, others were managed by the LSM framework itself. Starting with this pull we move management of all the LSM blobs, minus the XFRM blob, into the framework itself, improving consistency across LSMs, and reducing the amount of duplicated code across LSMs. Due to some additional work required to migrate the XFRM blob, it has been left as a todo item for a later date; from a practical standpoint this omission should have little impact as only SELinux provides a XFRM LSM implementation. - Fix problems with the LSM's handling of F_SETOWN The LSM hook for the fcntl(F_SETOWN) operation had a couple of problems: it was racy with itself, and it was disconnected from the associated DAC related logic in such a way that the LSM state could be updated in cases where the DAC state would not. We fix both of these problems by moving the security_file_set_fowner() hook into the same section of code where the DAC attributes are updated. Not only does this resolve the DAC/LSM synchronization issue, but as that code block is protected by a lock, it also resolve the race condition. - Fix potential problems with the security_inode_free() LSM hook Due to use of RCU to protect inodes and the placement of the LSM hook associated with freeing the inode, there is a bit of a challenge when it comes to managing any LSM state associated with an inode. The VFS folks are not open to relocating the LSM hook so we have to get creative when it comes to releasing an inode's LSM state. Traditionally we have used a single LSM callback within the hook that is triggered when the inode is "marked for death", but not actually released due to RCU. Unfortunately, this causes problems for LSMs which want to take an action when the inode's associated LSM state is actually released; so we add an additional LSM callback, inode_free_security_rcu(), that is called when the inode's LSM state is released in the RCU free callback. - Refactor two LSM hooks to better fit the LSM return value patterns The vast majority of the LSM hooks follow the "return 0 on success, negative values on failure" pattern, however, there are a small handful that have unique return value behaviors which has caused confusion in the past and makes it difficult for the BPF verifier to properly vet BPF LSM programs. This includes patches to convert two of these"special" LSM hooks to the common 0/-ERRNO pattern. - Various cleanups and improvements A handful of patches to remove redundant code, better leverage the IS_ERR_OR_NULL() helper, add missing "static" markings, and do some minor style fixups. * tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (40 commits) security: Update file_set_fowner documentation fs: Fix file_set_fowner LSM hook inconsistencies lsm: Use IS_ERR_OR_NULL() helper function lsm: remove LSM_COUNT and LSM_CONFIG_COUNT ipe: Remove duplicated include in ipe.c lsm: replace indirect LSM hook calls with static calls lsm: count the LSMs enabled at compile time kernel: Add helper macros for loop unrolling init/main.c: Initialize early LSMs after arch code, static keys and calls. MAINTAINERS: add IPE entry with Fan Wu as maintainer documentation: add IPE documentation ipe: kunit test for parser scripts: add boot policy generation program ipe: enable support for fs-verity as a trust provider fsverity: expose verified fsverity built-in signatures to LSMs lsm: add security_inode_setintegrity() hook ipe: add support for dm-verity as a trust provider dm-verity: expose root hash digest and signature data to LSMs block,lsm: add LSM blob and new LSM hooks for block devices ipe: add permissive toggle ...

Merge tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2024-09-16T07:14:02+00:00

Pull vfs file updates from Christian Brauner: "This is the work to cleanup and shrink struct file significantly. Right now, (focusing on x86) struct file is 232 bytes. After this series struct file will be 184 bytes aka 3 cacheline and a spare 8 bytes for future extensions at the end of the struct. With struct file being as ubiquitous as it is this should make a difference for file heavy workloads and allow further optimizations in the future. - struct fown_struct was embedded into struct file letting it take up 32 bytes in total when really it shouldn't even be embedded in struct file in the first place. Instead, actual users of struct fown_struct now allocate the struct on demand. This frees up 24 bytes. - Move struct file_ra_state into the union containg the cleanup hooks and move f_iocb_flags out of the union. This closes a 4 byte hole we created earlier and brings struct file to 192 bytes. Which means struct file is 3 cachelines and we managed to shrink it by 40 bytes. - Reorder struct file so that nothing crosses a cacheline. I suspect that in the future we will end up reordering some members to mitigate false sharing issues or just because someone does actually provide really good perf data. - Shrinking struct file to 192 bytes is only part of the work. Files use a slab that is SLAB_TYPESAFE_BY_RCU and when a kmem cache is created with SLAB_TYPESAFE_BY_RCU the free pointer must be located outside of the object because the cache doesn't know what part of the memory can safely be overwritten as it may be needed to prevent object recycling. That has the consequence that SLAB_TYPESAFE_BY_RCU may end up adding a new cacheline. So this also contains work to add a new kmem_cache_create_rcu() function that allows the caller to specify an offset where the freelist pointer is supposed to be placed. Thus avoiding the implicit addition of a fourth cacheline. - And finally this removes the f_version member in struct file. The f_version member isn't particularly well-defined. It is mainly used as a cookie to detect concurrent seeks when iterating directories. But it is also abused by some subsystems for completely unrelated things. It is mostly a directory and filesystem specific thing that doesn't really need to live in struct file and with its wonky semantics it really lacks a specific function. For pipes, f_version is (ab)used to defer poll notifications until a write has happened. And struct pipe_inode_info is used by multiple struct files in their ->private_data so there's no chance of pushing that down into file->private_data without introducing another pointer indirection. But pipes don't rely on f_pos_lock so this adds a union into struct file encompassing f_pos_lock and a pipe specific f_pipe member that pipes can use. This union of course can be extended to other file types and is similar to what we do in struct inode already" * tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits) fs: remove f_version pipe: use f_pipe fs: add f_pipe ubifs: store cookie in private data ufs: store cookie in private data udf: store cookie in private data proc: store cookie in private data ocfs2: store cookie in private data input: remove f_version abuse ext4: store cookie in private data ext2: store cookie in private data affs: store cookie in private data fs: add generic_llseek_cookie() fs: use must_set_pos() fs: add must_set_pos() fs: add vfs_setpos_cookie() s390: remove unused f_version ceph: remove unused f_version adi: remove unused f_version mm: Removed @freeptr_offset to prevent doc warning ...

smackfs: Use rcu_assign_pointer() to ensure safe assignment in smk_set_cipso

2024-09-03T15:37:17+00:00

In the `smk_set_cipso` function, the `skp->smk_netlabel.attr.mls.cat` field is directly assigned to a new value without using the appropriate RCU pointer assignment functions. According to RCU usage rules, this is illegal and can lead to unpredictable behavior, including data inconsistencies and impossible-to-diagnose memory corruption issues. This possible bug was identified using a static analysis tool developed by myself, specifically designed to detect RCU-related issues. To address this, the assignment is now done using rcu_assign_pointer(), which ensures that the pointer assignment is done safely, with the necessary memory barriers and synchronization. This change prevents potential RCU dereference issues by ensuring that the `cat` field is safely updated while still adhering to RCU's requirements. Fixes: 0817534ff9ea ("smackfs: Fix use-after-free in netlbl_catmap_walk()") Signed-off-by: Jiawei Ye Signed-off-by: Casey Schaufler