kernel/linux.git/security, branch v6.12.101

landlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path

2026-08-03T09:17:33+00:00

[ Upstream commit 4b80320ca7ed03d6e683f95b6066565dc97b9f92 ] LANDLOCK_SCOPE_SIGNAL must prevent a sandboxed process from signaling processes outside its Landlock domain. It can be bypassed through the asynchronous SIGIO delivery path. A sandboxed process that owns any file or socket can arm it with fcntl(fd, F_SETOWN, -pgid), fcntl(fd, F_SETSIG, SIGKILL) and O_ASYNC, so that an I/O event makes the kernel deliver the chosen signal to the whole process group. As the head of its process group's task list (the default position right after fork()) that group can also hold the non-sandboxed process that launched it, e.g. a supervisor or a security monitor. The sandbox can thus kill or signal the processes LANDLOCK_SCOPE_SIGNAL is meant to protect from it. The scope is enforced in hook_file_send_sigiotask() against the Landlock domain recorded at F_SETOWN time, not the live domain of the sender. control_current_fowner() decides whether to record that domain and skips recording it when the fowner target is in the caller's thread group, which is safe only for a single-task target (PIDTYPE_PID, PIDTYPE_TGID). For a process group (PIDTYPE_PGID) pid_task() returns only one member; recording is skipped whenever that member shares the caller's thread group, and hook_file_send_sigiotask() then lets the signal fan out to the whole group unchecked. Record the domain for every non single-process target so the scope is enforced against each group member at delivery time. That recording is necessary but not sufficient on its own: the kernel signals a process group through its members' thread-group leaders, and the leader of the registrant's own process can carry a different Landlock domain than the sibling thread that armed the owner. domain_is_scoped() would then deny that leader, even though commit 18eb75f3af40 ("landlock: Always allow signals between threads of the same process") requires same-process delivery to be allowed. hook_task_kill() avoids this by evaluating same_thread_group() live, per recipient; the SIGIO path instead delegates the whole decision to a single registration-time check, which a process-group fan-out cannot honor. So also record the registrant's thread group next to its domain and exempt it at delivery: hook_file_send_sigiotask() allows the signal whenever the recipient belongs to the registrant's own process, restoring the same-process guarantee while keeping out-of-domain group members blocked. The direct kill() path (hook_task_kill) already evaluates the live domain and is unaffected. Fixes: 18eb75f3af40 ("landlock: Always allow signals between threads of the same process") Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Reviewed-by: Günther Noack Link: https://patch.msgid.link/56bffc24f3d0d08b45a686a48e99766b0a0821fa.1780614610.git.hexlabsecurity@proton.me [mic: Check pid_type earlier and improve comment, fix commit message, fix comment formatting] Signed-off-by: Mickaël Salaün Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

landlock: Prepare to use credential instead of domain for fowner

2026-08-03T09:17:33+00:00

[ Upstream commit 79625f1b3a3df63d3289a0781fdf121bc42966f7 ] This cosmetic change is needed for audit support, specifically to be able to filter according to cross-execution boundaries. struct landlock_file_security's size stay the same for now but it will increase with struct landlock_cred_security's size. Only save Landlock domain in hook_file_set_fowner() if the current domain has LANDLOCK_SCOPE_SIGNAL, which was previously done for each hook_file_send_sigiotask() calls. This should improve a bit performance. Replace hardcoded LANDLOCK_SCOPE_SIGNAL with the signal_scope.scope variable. Use scoped guards for RCU read-side critical sections. Cc: Günther Noack Link: https://lore.kernel.org/r/20250320190717.2287696-8-mic@digikod.net Signed-off-by: Mickaël Salaün Stable-dep-of: 4b80320ca7ed ("landlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bpf: Reject BPF_MAP_TYPE_INODE_STORAGE creation if BPF LSM is uninitialized

2026-07-24T14:11:55+00:00

commit a6f0643e4f63cfaa0d5d4a69de4f132eac4b8fe4 upstream. When CONFIG_BPF_LSM=y is set, BPF inode storage maps (BPF_MAP_TYPE_INODE_STORAGE) are compiled into the kernel. However, if the BPF LSM is not explicitly enabled at boot time (e.g. omitted from the "lsm=" boot parameter), lsm_prepare() is never executed for the BPF LSM. Consequently, the BPF inode security blob offset (bpf_lsm_blob_sizes.lbs_inode) is never initialized and remains at its default compiled size of 8 bytes instead of being updated to a valid offset past the reserved struct rcu_head (typically 16 bytes or more). When a privileged user creates and updates a BPF_MAP_TYPE_INODE_STORAGE map, bpf_inode() evaluates inode->i_security + 8. This erroneously aliases the struct rcu_head.func callback pointer at the beginning of the inode->i_security blob. During subsequent map element cleanup or inode destruction, writing NULL to owner_storage clears the queued RCU callback pointer. When rcu_do_batch() later executes the queued callback, it attempts an instruction fetch at address 0x0, triggering an immediate kernel panic. Fix this by introducing a global bpf_lsm_initialized boolean flag marked with __ro_after_init. Set this flag to true inside bpf_lsm_init() when the LSM framework successfully registers the BPF LSM. Gate map allocation in inode_storage_map_alloc() on this flag, returning -EOPNOTSUPP if the BPF LSM is in turn uninitialized. This fail-fast approach prevents userspace from allocating inode storage maps when the supporting BPF LSM infrastructure is absent, avoiding zombie map states. Fixes: 8ea636848aca ("bpf: Implement bpf_local_storage for inodes") Reported-by: oxsignal Signed-off-by: Matt Bobrowski Signed-off-by: Daniel Borkmann Reviewed-by: Emil Tsalapatis Reviewed-by: Amery Hung Link: https://lore.kernel.org/bpf/20260628201103.3624525-1-mattbobrowski@google.com Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

selinux: fix incorrect execmem checks on overlayfs

2026-07-24T14:11:29+00:00

commit 9fe595fad54d4ac6a402edb3f60bec859d52cea6 upstream. The commit fixing the overlayfs mmap() and mprotect() access checks failed to skip the execmem check in __file_map_prot_check() for the case where the "mounter check" is being performed. This check should be performed only against the credentials of the task that is calling mmap()/mprotect(), since it doesn't pertain to the file itself, but rather just gates the ability of the calling task to get an executable memory mapping in general. The purpose of the "mounter check" is to guard against using an overlayfs mount to gain file access that would otherwise be denied to the mounter. For execmem this is not relevant, as there is no further file access granted based on it (notice that the file's context is not used as the target in the check), so checking it also against the mounter credentials would be incorrect. Fix this by passing a boolean to [__]file_map_prot_check() and selinux_mmap_file_common() that indicates if we are doing the "mounter check" and skiping the execmem check in that case. Since this boolean also indicates if we use current_cred() or the mounter cred as the subject, also remove the "cred" argument from these functions and determine it based on the boolean and the file struct. Cc: stable@vger.kernel.org Fixes: 82544d36b172 ("selinux: fix overlayfs mmap() and mprotect() access checks") Signed-off-by: Ondrej Mosnacek Reviewed-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

selinux: avoid sk_socket dereference in selinux_sctp_bind_connect()

2026-07-24T14:11:29+00:00

commit 56acfeb10019e200ab6787d01f8d7cbe0f01526f upstream. selinux_sctp_bind_connect() dereferences sk->sk_socket to pass a struct socket * to selinux_socket_bind() and selinux_socket_connect_helper(). However, when the hook is invoked from the ASCONF softirq path (sctp_process_asconf), there is no file reference guaranteeing that sk->sk_socket is non-NULL. The setsockopt callers (bindx, connectx, set_primary, sendmsg connect) hold a file reference and are not affected. Both selinux_socket_bind() and selinux_socket_connect_helper() immediately resolve sock->sk, never using the struct socket * for anything else. Refactor the inner logic into helpers that take a struct sock * directly so that selinux_sctp_bind_connect() never needs to touch sk->sk_socket at all. Cc: stable@vger.kernel.org Fixes: d452930fd3b9 ("selinux: Add SCTP support") Suggested-by: Stephen Smalley Signed-off-by: Tristan Madani Reviewed-by: Stephen Smalley Tested-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

selinux: check connect-related permissions on TCP Fast Open

2026-07-24T14:11:29+00:00

commit 44c74d27d1b9aaa99fa8a83640c1223575262b80 upstream. Similar to Landlock, SELinux was not updated when TCP Fast Open support was introduced to ensure connect-related permissions are checked when using TCP Fast Open. Update its socket_sendmsg() hook to call selinux_socket_connect() when MSG_FASTOPEN is passed. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-security-module/20260616201615.275032-1-hexlabsecurity@proton.me/ Link: https://lore.kernel.org/linux-security-module/20260617180526.15627-2-matthieu@buffet.re/ Reported-by: Bryam Vargas Reported-by: Matthieu Buffet Reported-by: Mikhail Ivanov Signed-off-by: Stephen Smalley Tested-by: Bryam Vargas Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

apparmor: fix label can not be immediately before a declaration

2026-07-24T14:11:10+00:00

[ Upstream commit 1ed40bd525c00d22af666016af9aef7167f8085f ] Fix error reported by kernel test robot security/apparmor/policy.c:1381:2: error: a label can only be part of a statement and a declaration is not a statement All errors (new ones prefixed by >>): security/apparmor/policy.c: In function 'aa_replace_profiles': >> security/apparmor/policy.c:1381:2: error: a label can only be part of a statement and a declaration is not a statement ssize_t udata_sz = udata->size; ^~~~~ Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202606150525.npax8WiH-lkp@intel.com/ Fixes: 7b42f95813dc9 ("apparmor: fix potential UAF in aa_replace_profiles") Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: put secmark label after secid lookup

2026-07-24T14:11:09+00:00

[ Upstream commit 340372688bb87da45ff8d4e2f82ccfd1b64c65ff ] apparmor_secmark_init() parses a configured secmark label to obtain its secid. aa_label_strn_parse() returns a refcounted label, but the success path kept that reference after copying the secid. Fixes: ab9f2115081a ("apparmor: Allow filtering based on secmark policy") Signed-off-by: Zygmunt Krynicki Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: aa_getprocattr free procattr leak on format failure

2026-07-24T14:11:09+00:00

[ Upstream commit fea23bf73f0cae8ccb1d0684e4a3003874771f41 ] aa_getprocattr() allocates the output string before rendering the label into it. If the second aa_label_snxprint() call fails, the function returned without freeing that allocation. Free and clear the output pointer on the uncommon formatting failure path before dropping the namespace reference. Fixes: 76a1d263aba3 ("apparmor: switch getprocattr to using label_print fns()") Reviewed-by: Tyler Hicks Reviewed-by: Ryan Lee Signed-off-by: Zygmunt Krynicki Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: remove or add symlinks to rawdata according to export_binary

2026-07-24T14:11:09+00:00

[ Upstream commit 59fe6fbc4cd45582bc8893de0a382a36562317b3 ] When the export_binary parameter is set, then rawdata is available and there should be a symbolic link for the rawdata in the profile directory in apparmorfs. If the parameter is unset, then the symlinks should not exist. The issue arises when changing the value of export_binary on runtime and replacing profiles. If export_binary was set when the profile was originally loaded, then changed to 0 and the profile was reloaded, then the symbolic links would still exist but would return ENOENT because the rawdata no longer exists. On the opposite side, if export_binary was unset when the profile was originally loaded, then changed to 1 and the profile was reloaded, then the symbolic links would not exist, even though the rawdata does. Fixes: d61c57fde8191 ("apparmor: make export of raw binary profile to userspace optional") Signed-off-by: Georgia Garcia Signed-off-by: John Johansen Signed-off-by: Sasha Levin