kernel/linux.git/security/smack, branch v6.6.40

ima: Avoid blocking in RCU read-side critical section

2024-07-11T10:49:18+00:00

commit 9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 upstream. A panic happens in ima_match_policy: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 PGD 42f873067 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 5 PID: 1286325 Comm: kubeletmonit.sh Kdump: loaded Tainted: P Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 RIP: 0010:ima_match_policy+0x84/0x450 Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39 7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea 44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f RSP: 0018:ff71570009e07a80 EFLAGS: 00010207 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200 RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739 R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970 R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001 FS: 00007f5195b51740(0000) GS:ff3e278b12d40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ima_get_action+0x22/0x30 process_measurement+0xb0/0x830 ? page_add_file_rmap+0x15/0x170 ? alloc_set_pte+0x269/0x4c0 ? prep_new_page+0x81/0x140 ? simple_xattr_get+0x75/0xa0 ? selinux_file_open+0x9d/0xf0 ima_file_check+0x64/0x90 path_openat+0x571/0x1720 do_filp_open+0x9b/0x110 ? page_counter_try_charge+0x57/0xc0 ? files_cgroup_alloc_fd+0x38/0x60 ? __alloc_fd+0xd4/0x250 ? do_sys_open+0x1bd/0x250 do_sys_open+0x1bd/0x250 do_syscall_64+0x5d/0x1d0 entry_SYSCALL_64_after_hwframe+0x65/0xca Commit c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()") introduced call to ima_lsm_copy_rule within a RCU read-side critical section which contains kmalloc with GFP_KERNEL. This implies a possible sleep and violates limitations of RCU read-side critical sections on non-PREEMPT systems. Sleeping within RCU read-side critical section might cause synchronize_rcu() returning early and break RCU protection, allowing a UAF to happen. The root cause of this issue could be described as follows: | Thread A | Thread B | | |ima_match_policy | | | rcu_read_lock | |ima_lsm_update_rule | | | synchronize_rcu | | | | kmalloc(GFP_KERNEL)| | | sleep | ==> synchronize_rcu returns early | kfree(entry) | | | | entry = entry->next| ==> UAF happens and entry now becomes NULL (or could be anything). | | entry->action | ==> Accessing entry might cause panic. To fix this issue, we are converting all kmalloc that is called within RCU read-side critical section to use GFP_ATOMIC. Fixes: c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()") Cc: stable@vger.kernel.org Signed-off-by: GUO Zihua Acked-by: John Johansen Reviewed-by: Mimi Zohar Reviewed-by: Casey Schaufler [PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case] Signed-off-by: Paul Moore Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman

smack: Handle SMACK64TRANSMUTE in smack_inode_setsecurity()

2024-04-03T13:28:16+00:00

[ Upstream commit ac02f007d64eb2769d0bde742aac4d7a5fc6e8a5 ] If the SMACK64TRANSMUTE xattr is provided, and the inode is a directory, update the in-memory inode flags by setting SMK_INODE_TRANSMUTE. Cc: stable@vger.kernel.org Fixes: 5c6d1125f8db ("Smack: Transmute labels on specified directories") # v2.6.38.x Signed-off-by: Roberto Sassu Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin

smack: Set SMACK64TRANSMUTE only for dirs in smack_inode_setxattr()

2024-04-03T13:28:16+00:00

[ Upstream commit 9c82169208dde516510aaba6bbd8b13976690c5d ] Since the SMACK64TRANSMUTE xattr makes sense only for directories, enforce this restriction in smack_inode_setxattr(). Cc: stable@vger.kernel.org Fixes: 5c6d1125f8db ("Smack: Transmute labels on specified directories") # v2.6.38.x Signed-off-by: Roberto Sassu Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin

lsm: new security_file_ioctl_compat() hook

2024-02-01T00:18:54+00:00

commit f1bb47a31dff6d4b34fb14e99850860ee74bb003 upstream. Some ioctl commands do not require ioctl permission, but are routed to other permissions such as FILE_GETATTR or FILE_SETATTR. This routing is done by comparing the ioctl cmd to a set of 64-bit flags (FS_IOC_*). However, if a 32-bit process is running on a 64-bit kernel, it emits 32-bit flags (FS_IOC32_*) for certain ioctl operations. These flags are being checked erroneously, which leads to these ioctl operations being routed to the ioctl permission, rather than the correct file permissions. This was also noted in a RED-PEN finding from a while back - "/* RED-PEN how should LSM module know it's handling 32bit? */". This patch introduces a new hook, security_file_ioctl_compat(), that is called from the compat ioctl syscall. All current LSMs have been changed to support this hook. Reviewing the three places where we are currently using security_file_ioctl(), it appears that only SELinux needs a dedicated compat change; TOMOYO and SMACK appear to be functional without any change. Cc: stable@vger.kernel.org Fixes: 0b24dcb7f2f7 ("Revert "selinux: simplify ioctl checking"") Signed-off-by: Alfred Piccioni Reviewed-by: Stephen Smalley [PM: subject tweak, line length fixes, and alignment corrections] Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

Merge tag 'Smack-for-6.6' of https://github.com/cschaufler/smack-next

2023-08-30T16:28:07+00:00

Pull smack updates from Casey Schaufler: "Two minor fixes: is a simple spelling fix. The other is a bounds check for a very likely underflow" * tag 'Smack-for-6.6' of https://github.com/cschaufler/smack-next: smackfs: Prevent underflow in smk_set_cipso() security: smack: smackfs: fix typo (lables->labels)

Merge tag 'lsm-pr-20230829' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

2023-08-30T16:07:09+00:00

Pull LSM updates from Paul Moore: - Add proper multi-LSM support for xattrs in the security_inode_init_security() hook Historically the LSM layer has only allowed a single LSM to add an xattr to an inode, with IMA/EVM measuring that and adding its own as well. As we work towards promoting IMA/EVM to a "proper LSM" instead of the special case that it is now, we need to better support the case of multiple LSMs each adding xattrs to an inode and after several attempts we now appear to have something that is working well. It is worth noting that in the process of making this change we uncovered a problem with Smack's SMACK64TRANSMUTE xattr which is also fixed in this pull request. - Additional LSM hook constification Two patches to constify parameters to security_capget() and security_binder_transfer_file(). While I generally don't make a special note of who submitted these patches, these were the work of an Outreachy intern, Khadija Kamran, and that makes me happy; hopefully it does the same for all of you reading this. - LSM hook comment header fixes One patch to add a missing hook comment header, one to fix a minor typo. - Remove an old, unused credential function declaration It wasn't clear to me who should pick this up, but it was trivial, obviously correct, and arguably the LSM layer has a vested interest in credentials so I merged it. Sadly I'm now noticing that despite my subject line cleanup I didn't cleanup the "unsued" misspelling, sigh * tag 'lsm-pr-20230829' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: lsm: constify the 'file' parameter in security_binder_transfer_file() lsm: constify the 'target' parameter in security_capget() lsm: add comment block for security_sk_classify_flow LSM hook security: Fix ret values doc for security_inode_init_security() cred: remove unsued extern declaration change_create_files_as() evm: Support multiple LSMs providing an xattr evm: Align evm_inode_init_security() definition with LSM infrastructure smack: Set the SMACK64TRANSMUTE xattr in smack_inode_init_security() security: Allow all LSMs to provide xattrs for inode_init_security hook lsm: fix typo in security_file_lock() comment header

vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing

2023-08-15T06:32:30+00:00

When NFS superblocks are created by automounting, their LSM parameters aren't set in the fs_context struct prior to sget_fc() being called, leading to failure to match existing superblocks. This bug leads to messages like the following appearing in dmesg when fscache is enabled: NFS: Cache volume key already in use (nfs,4.2,2,108,106a8c0,1,,,,100000,100000,2ee,3a98,1d4c,3a98,1) Fix this by adding a new LSM hook to load fc->security for submount creation. Signed-off-by: David Howells Signed-off-by: Jeff Layton Link: https://lore.kernel.org/r/165962680944.3334508.6610023900349142034.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/165962729225.3357250.14350728846471527137.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/165970659095.2812394.6868894171102318796.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/166133579016.3678898.6283195019480567275.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/217595.1662033775@warthog.procyon.org.uk/ # v5 Fixes: 9bc61ab18b1d ("vfs: Introduce fs_context, switch vfs_kern_mount() to it.") Fixes: 779df6a5480f ("NFS: Ensure security label is set for root inode") Tested-by: Jeff Layton Acked-by: Casey Schaufler Acked-by: "Christian Brauner (Microsoft)" Acked-by: Paul Moore Reviewed-by: Jeff Layton Message-Id: <20230808-master-v9-1-e0ecde888221@kernel.org> Signed-off-by: Christian Brauner

smackfs: Prevent underflow in smk_set_cipso()

2023-08-07T21:09:23+00:00

There is a upper bound to "catlen" but no lower bound to prevent negatives. I don't see that this necessarily causes a problem but we may as well be safe. Fixes: e114e473771c ("Smack: Simplified Mandatory Access Control Kernel") Signed-off-by: Dan Carpenter Signed-off-by: Casey Schaufler

security: smack: smackfs: fix typo (lables->labels)

2023-08-07T21:09:23+00:00

Fix a spelling error in smakcfs. Signed-off-by: Tóth János Signed-off-by: Casey Schaufler

smack: Set the SMACK64TRANSMUTE xattr in smack_inode_init_security()

2023-07-10T17:59:38+00:00

With the newly added ability of LSMs to supply multiple xattrs, set SMACK64TRASMUTE in smack_inode_init_security(), instead of d_instantiate(). Do it by incrementing SMACK_INODE_INIT_XATTRS to 2 and by calling lsm_get_xattr_slot() a second time, if the transmuting conditions are met. The LSM infrastructure passes all xattrs provided by LSMs to the filesystems through the initxattrs() callback, so that filesystems can store xattrs in the disk. After the change, the SMK_INODE_TRANSMUTE inode flag is always set by d_instantiate() after fetching SMACK64TRANSMUTE from the disk. Before it was done by smack_inode_post_setxattr() as result of the __vfs_setxattr() call. Removing __vfs_setxattr() also prevents invalidating the EVM HMAC, by adding a new xattr without checking and updating the existing HMAC. Signed-off-by: Roberto Sassu Reviewed-by: Casey Schaufler Signed-off-by: Paul Moore