kernel/linux.git/security/apparmor, 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

apparmor: avoid crash when parsed profile name is empty

2024-01-25T23:35:54+00:00

[ Upstream commit 55a8210c9e7d21ff2644809699765796d4bfb200 ] When processing a packed profile in unpack_profile() described like "profile :ns::samba-dcerpcd /usr/lib*/samba/{,samba/}samba-dcerpcd {...}" a string ":samba-dcerpcd" is unpacked as a fully-qualified name and then passed to aa_splitn_fqname(). aa_splitn_fqname() treats ":samba-dcerpcd" as only containing a namespace. Thus it returns NULL for tmpname, meanwhile tmpns is non-NULL. Later aa_alloc_profile() crashes as the new profile name is NULL now. general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 6 PID: 1657 Comm: apparmor_parser Not tainted 6.7.0-rc2-dirty #16 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:strlen+0x1e/0xa0 Call Trace: ? strlen+0x1e/0xa0 aa_policy_init+0x1bb/0x230 aa_alloc_profile+0xb1/0x480 unpack_profile+0x3bc/0x4960 aa_unpack+0x309/0x15e0 aa_replace_profiles+0x213/0x33c0 policy_update+0x261/0x370 profile_replace+0x20e/0x2a0 vfs_write+0x2af/0xe00 ksys_write+0x126/0x250 do_syscall_64+0x46/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 ---[ end trace 0000000000000000 ]--- RIP: 0010:strlen+0x1e/0xa0 It seems such behaviour of aa_splitn_fqname() is expected and checked in other places where it is called (e.g. aa_remove_profiles). Well, there is an explicit comment "a ns name without a following profile is allowed" inside. AFAICS, nothing can prevent unpacked "name" to be in form like ":samba-dcerpcd" - it is passed from userspace. Deny the whole profile set replacement in such case and inform user with EPROTO and an explaining message. Found by Linux Verification Center (linuxtesting.org). Fixes: 04dc715e24d0 ("apparmor: audit policy ns specified in policy load") Signed-off-by: Fedor Pchelkin Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: fix possible memory leak in unpack_trans_table

2024-01-25T23:35:54+00:00

[ Upstream commit 1342ad786073e96fa813ad943c19f586157ae297 ] If we fail to unpack the transition table then the table elements which have been already allocated are not freed on error path. unreferenced object 0xffff88802539e000 (size 128): comm "apparmor_parser", pid 903, jiffies 4294914938 (age 35.085s) hex dump (first 32 bytes): 20 73 6f 6d 65 20 6e 61 73 74 79 20 73 74 72 69 some nasty stri 6e 67 20 73 6f 6d 65 20 6e 61 73 74 79 20 73 74 ng some nasty st backtrace: [] __kmem_cache_alloc_node+0x1e2/0x2d0 [] __kmalloc_node_track_caller+0x54/0x170 [] kmemdup+0x29/0x60 [] aa_unpack_strdup+0xe5/0x1b0 [] unpack_pdb+0xeb8/0x2700 [] unpack_profile+0x1507/0x4a30 [] aa_unpack+0x36a/0x1560 [] aa_replace_profiles+0x213/0x33c0 [] policy_update+0x261/0x370 [] profile_replace+0x20e/0x2a0 [] vfs_write+0x2af/0xe00 [] ksys_write+0x126/0x250 [] do_syscall_64+0x46/0xf0 [] entry_SYSCALL_64_after_hwframe+0x6e/0x76 Call aa_free_str_table() on error path as was done before the blamed commit. It implements all necessary checks, frees str_table if it is available and nullifies the pointers. Found by Linux Verification Center (linuxtesting.org). Fixes: a0792e2ceddc ("apparmor: make transition table unpack generic so it can be reused") Signed-off-by: Fedor Pchelkin Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: Fix ref count leak in task_kill

2024-01-25T23:35:54+00:00

[ Upstream commit 2cb54a19ac7153b9a26a72098c495187f64c2276 ] apparmor_task_kill was not putting the task_cred reference tc, or the cred_label reference tc when dealing with a passed in cred, fix this by using a single fn exit. Fixes: 90c436a64a6e ("apparmor: pass cred through to audit info.") Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: Fix move_mount mediation by detecting if source is detached

2024-01-10T16:16:52+00:00

[ Upstream commit 8026e40608b4d552216d2a818ca7080a4264bb44 ] Prevent move_mount from applying the attach_disconnected flag to move_mount(). This prevents detached mounts from appearing as / when applying mount mediation, which is not only incorrect but could result in bad policy being generated. Basic mount rules like allow mount, allow mount options=(move) -> /target/, will allow detached mounts, allowing older policy to continue to function. New policy gains the ability to specify `detached` as a source option allow mount detached -> /target/, In addition make sure support of move_mount is advertised as a feature to userspace so that applications that generate policy can respond to the addition. Note: this fixes mediation of move_mount when a detached mount is used, it does not fix the broader regression of apparmor mediation of mounts under the new mount api. Link: https://lore.kernel.org/all/68c166b8-5b4d-4612-8042-1dee3334385b@leemhuis.info/T/#mb35fdde37f999f08f0b02d58dc1bf4e6b65b8da2 Fixes: 157a3537d6bc ("apparmor: Fix regression in mount mediation") Reviewed-by: Georgia Garcia Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: Fix regression in mount mediation

2023-11-28T17:20:07+00:00

[ Upstream commit 157a3537d6bc28ceb9a11fc8cb67f2152d860146 ] commit 2db154b3ea8e ("vfs: syscall: Add move_mount(2) to move mounts around") introduced a new move_mount(2) system call and a corresponding new LSM security_move_mount hook but did not implement this hook for any existing LSM. This creates a regression for AppArmor mediation of mount. This patch provides a base mapping of the move_mount syscall to the existing mount mediation. In the future we may introduce additional mediations around the new mount calls. Fixes: 2db154b3ea8e ("vfs: syscall: Add move_mount(2) to move mounts around") CC: stable@vger.kernel.org Reported-by: Andreas Steinmetz Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: pass cred through to audit info.

2023-11-28T17:20:07+00:00

[ Upstream commit 90c436a64a6e20482a9a613c47eb4af2e8a5328e ] The cred is needed to properly audit some messages, and will be needed in the future for uid conditional mediation. So pass it through to where the apparmor_audit_data struct gets defined. Reviewed-by: Georgia Garcia Signed-off-by: John Johansen Stable-dep-of: 157a3537d6bc ("apparmor: Fix regression in mount mediation") Signed-off-by: Sasha Levin

apparmor: rename audit_data->label to audit_data->subj_label

2023-11-28T17:20:07+00:00

[ Upstream commit d20f5a1a6e792d22199c9989ec7ab9e95c48d60c ] rename audit_data's label field to subj_label to better reflect its use. Also at the same time drop unneeded assignments to ->subj_label as the later call to aa_check_perms will do the assignment if needed. Reviewed-by: Georgia Garcia Signed-off-by: John Johansen Stable-dep-of: 157a3537d6bc ("apparmor: Fix regression in mount mediation") Signed-off-by: Sasha Levin

apparmor: combine common_audit_data and apparmor_audit_data

2023-11-28T17:20:07+00:00

[ Upstream commit bd7bd201ca46c211c3ab251ca9854787d1331a2f ] Everywhere where common_audit_data is used apparmor audit_data is also used. We can simplify the code and drop the use of the aad macro everywhere by combining the two structures. Reviewed-by: Georgia Garcia Signed-off-by: John Johansen Stable-dep-of: 157a3537d6bc ("apparmor: Fix regression in mount mediation") Signed-off-by: Sasha Levin

apparmor: Fix kernel-doc warnings in apparmor/policy.c

2023-11-28T17:20:07+00:00

[ Upstream commit 25ff0ff2d6286928dc516c74b879809c691c2dd8 ] Fix kernel-doc warnings: security/apparmor/policy.c:294: warning: Function parameter or member 'proxy' not described in 'aa_alloc_profile' security/apparmor/policy.c:785: warning: Function parameter or member 'label' not described in 'aa_policy_view_capable' security/apparmor/policy.c:785: warning: Function parameter or member 'ns' not described in 'aa_policy_view_capable' security/apparmor/policy.c:847: warning: Function parameter or member 'ns' not described in 'aa_may_manage_policy' security/apparmor/policy.c:964: warning: Function parameter or member 'hname' not described in '__lookup_replace' security/apparmor/policy.c:964: warning: Function parameter or member 'info' not described in '__lookup_replace' security/apparmor/policy.c:964: warning: Function parameter or member 'noreplace' not described in '__lookup_replace' security/apparmor/policy.c:964: warning: Function parameter or member 'ns' not described in '__lookup_replace' security/apparmor/policy.c:964: warning: Function parameter or member 'p' not described in '__lookup_replace' Signed-off-by: Gaosheng Cui Signed-off-by: John Johansen Stable-dep-of: 157a3537d6bc ("apparmor: Fix regression in mount mediation") Signed-off-by: Sasha Levin