linux-stable.git/security/smack, branch linux-6.10.y Linux kernel stable tree lsm: infrastructure management of the sock security 2024-10-04T14:33:46+00:00 Casey Schaufler casey@schaufler-ca.com 2024-07-10T21:32:25+00:00 fbec4ba70f789cb4d8fed3029d3ddf8a01f68e89 [ Upstream commit 2aff9d20d50ac45dd13a013ef5231f4fb8912356 ] Move management of the sock->sk_security blob out of the individual security modules and into the security infrastructure. Instead of allocating the blobs from within the modules the modules tell the infrastructure how much space is required, and the space is allocated there. Acked-by: Paul Moore <paul@paul-moore.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: John Johansen <john.johansen@canonical.com> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subject tweak] Signed-off-by: Paul Moore <paul@paul-moore.com> Stable-dep-of: 63dff3e48871 ("lsm: add the inode_free_security_rcu() LSM implementation hook") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 2aff9d20d50ac45dd13a013ef5231f4fb8912356 ]

Move management of the sock->sk_security blob out
of the individual security modules and into the security
infrastructure. Instead of allocating the blobs from within
the modules the modules tell the infrastructure how much
space is required, and the space is allocated there.

Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Stable-dep-of: 63dff3e48871 ("lsm: add the inode_free_security_rcu() LSM implementation hook")
Signed-off-by: Sasha Levin <sashal@kernel.org>
smackfs: Use rcu_assign_pointer() to ensure safe assignment in smk_set_cipso 2024-10-04T14:32:57+00:00 Jiawei Ye jiawei.ye@foxmail.com 2024-09-02T08:47:26+00:00 df480091e6f71f4d2b40636eeb549518571cc123 [ Upstream commit 2749749afa071f8a0e405605de9da615e771a7ce ] 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 <jiawei.ye@foxmail.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 2749749afa071f8a0e405605de9da615e771a7ce ]

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 <jiawei.ye@foxmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: unix sockets: fix accept()ed socket label 2024-09-12T09:12:50+00:00 Konstantin Andreev andreev@swemel.ru 2024-06-16T22:44:30+00:00 73656d1f4a74857f4f65942c2ad0cadff264df76 [ Upstream commit e86cac0acdb1a74f608bacefe702f2034133a047 ] When a process accept()s connection from a unix socket (either stream or seqpacket) it gets the socket with the label of the connecting process. For example, if a connecting process has a label 'foo', the accept()ed socket will also have 'in' and 'out' labels 'foo', regardless of the label of the listener process. This is because kernel creates unix child sockets in the context of the connecting process. I do not see any obvious way for the listener to abuse alien labels coming with the new socket, but, to be on the safe side, it's better fix new socket labels. Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e86cac0acdb1a74f608bacefe702f2034133a047 ]

When a process accept()s connection from a unix socket
(either stream or seqpacket)
it gets the socket with the label of the connecting process.

For example, if a connecting process has a label 'foo',
the accept()ed socket will also have 'in' and 'out' labels 'foo',
regardless of the label of the listener process.

This is because kernel creates unix child sockets
in the context of the connecting process.

I do not see any obvious way for the listener to abuse
alien labels coming with the new socket, but,
to be on the safe side, it's better fix new socket labels.

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
smack: tcp: ipv4, fix incorrect labeling 2024-09-08T05:56:35+00:00 Casey Schaufler casey@schaufler-ca.com 2024-06-05T22:41:50+00:00 d3703fa94116fed91f64c7d1c7d284fb4369070f [ Upstream commit 2fe209d0ad2e2729f7e22b9b31a86cc3ff0db550 ] Currently, Smack mirrors the label of incoming tcp/ipv4 connections: when a label 'foo' connects to a label 'bar' with tcp/ipv4, 'foo' always gets 'foo' in returned ipv4 packets. So, 1) returned packets are incorrectly labeled ('foo' instead of 'bar') 2) 'bar' can write to 'foo' without being authorized to write. Here is a scenario how to see this: * Take two machines, let's call them C and S, with active Smack in the default state (no settings, no rules, no labeled hosts, only builtin labels) * At S, add Smack rule 'foo bar w' (labels 'foo' and 'bar' are instantiated at S at this moment) * At S, at label 'bar', launch a program that listens for incoming tcp/ipv4 connections * From C, at label 'foo', connect to the listener at S. (label 'foo' is instantiated at C at this moment) Connection succeedes and works. * Send some data in both directions. * Collect network traffic of this connection. All packets in both directions are labeled with the CIPSO of the label 'foo'. Hence, label 'bar' writes to 'foo' without being authorized, and even without ever being known at C. If anybody cares: exactly the same happens with DCCP. This behavior 1st manifested in release 2.6.29.4 (see Fixes below) and it looks unintentional. At least, no explanation was provided. I changed returned packes label into the 'bar', to bring it into line with the Smack documentation claims. Signed-off-by: Konstantin Andreev <andreev@swemel.ru> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 2fe209d0ad2e2729f7e22b9b31a86cc3ff0db550 ]

Currently, Smack mirrors the label of incoming tcp/ipv4 connections:
when a label 'foo' connects to a label 'bar' with tcp/ipv4,
'foo' always gets 'foo' in returned ipv4 packets. So,
1) returned packets are incorrectly labeled ('foo' instead of 'bar')
2) 'bar' can write to 'foo' without being authorized to write.

Here is a scenario how to see this:

* Take two machines, let's call them C and S,
   with active Smack in the default state
   (no settings, no rules, no labeled hosts, only builtin labels)

* At S, add Smack rule 'foo bar w'
   (labels 'foo' and 'bar' are instantiated at S at this moment)

* At S, at label 'bar', launch a program
   that listens for incoming tcp/ipv4 connections

* From C, at label 'foo', connect to the listener at S.
   (label 'foo' is instantiated at C at this moment)
   Connection succeedes and works.

* Send some data in both directions.
* Collect network traffic of this connection.

All packets in both directions are labeled with the CIPSO
of the label 'foo'. Hence, label 'bar' writes to 'foo' without
being authorized, and even without ever being known at C.

If anybody cares: exactly the same happens with DCCP.

This behavior 1st manifested in release 2.6.29.4 (see Fixes below)
and it looks unintentional. At least, no explanation was provided.

I changed returned packes label into the 'bar',
to bring it into line with the Smack documentation claims.

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
selinux,smack: don't bypass permissions check in inode_setsecctx hook 2024-09-04T11:30:06+00:00 Scott Mayhew smayhew@redhat.com 2024-08-28T19:51:29+00:00 f71ec019257ba4f7ab198bd948c5902a207bad96 commit 76a0e79bc84f466999fa501fce5bf7a07641b8a7 upstream. Marek Gresko reports that the root user on an NFS client is able to change the security labels on files on an NFS filesystem that is exported with root squashing enabled. The end of the kerneldoc comment for __vfs_setxattr_noperm() states: * This function requires the caller to lock the inode's i_mutex before it * is executed. It also assumes that the caller will make the appropriate * permission checks. nfsd_setattr() does do permissions checking via fh_verify() and nfsd_permission(), but those don't do all the same permissions checks that are done by security_inode_setxattr() and its related LSM hooks do. Since nfsd_setattr() is the only consumer of security_inode_setsecctx(), simplest solution appears to be to replace the call to __vfs_setxattr_noperm() with a call to __vfs_setxattr_locked(). This fixes the above issue and has the added benefit of causing nfsd to recall conflicting delegations on a file when a client tries to change its security label. Cc: stable@kernel.org Reported-by: Marek Gresko <marek.gresko@protonmail.com> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218809 Signed-off-by: Scott Mayhew <smayhew@redhat.com> Tested-by: Stephen Smalley <stephen.smalley.work@gmail.com> Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 76a0e79bc84f466999fa501fce5bf7a07641b8a7 upstream.

Marek Gresko reports that the root user on an NFS client is able to
change the security labels on files on an NFS filesystem that is
exported with root squashing enabled.

The end of the kerneldoc comment for __vfs_setxattr_noperm() states:

 *  This function requires the caller to lock the inode's i_mutex before it
 *  is executed. It also assumes that the caller will make the appropriate
 *  permission checks.

nfsd_setattr() does do permissions checking via fh_verify() and
nfsd_permission(), but those don't do all the same permissions checks
that are done by security_inode_setxattr() and its related LSM hooks do.

Since nfsd_setattr() is the only consumer of security_inode_setsecctx(),
simplest solution appears to be to replace the call to
__vfs_setxattr_noperm() with a call to __vfs_setxattr_locked().  This
fixes the above issue and has the added benefit of causing nfsd to
recall conflicting delegations on a file when a client tries to change
its security label.

Cc: stable@kernel.org
Reported-by: Marek Gresko <marek.gresko@protonmail.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218809
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Tested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
selinux,smack: remove the capability checks in the removexattr hooks 2024-08-03T07:01:09+00:00 Paul Moore paul@paul-moore.com 2024-07-03T21:00:20+00:00 bc8ccc1f1e079aac885e4d62efaa63159bf2b7c8 commit dd44477e7fa15ba3b100dfc67bf7cf083f3dccf6 upstream. Commit 61df7b828204 ("lsm: fixup the inode xattr capability handling") moved the responsibility of doing the inode xattr capability checking out of the individual LSMs and into the LSM framework itself. Unfortunately, while the original commit added the capability checks to both the setxattr and removexattr code in the LSM framework, it only removed the setxattr capability checks from the individual LSMs, leaving duplicated removexattr capability checks in both the SELinux and Smack code. This patch removes the duplicated code from SELinux and Smack. Fixes: 61df7b828204 ("lsm: fixup the inode xattr capability handling") Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit dd44477e7fa15ba3b100dfc67bf7cf083f3dccf6 upstream.

Commit 61df7b828204 ("lsm: fixup the inode xattr capability handling")
moved the responsibility of doing the inode xattr capability checking
out of the individual LSMs and into the LSM framework itself.
Unfortunately, while the original commit added the capability checks
to both the setxattr and removexattr code in the LSM framework, it
only removed the setxattr capability checks from the individual LSMs,
leaving duplicated removexattr capability checks in both the SELinux
and Smack code.

This patch removes the duplicated code from SELinux and Smack.

Fixes: 61df7b828204 ("lsm: fixup the inode xattr capability handling")
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
lsm: fixup the inode xattr capability handling 2024-08-03T07:00:34+00:00 Paul Moore paul@paul-moore.com 2024-05-02T21:57:51+00:00 e71327a647a5879dd35fbbdb3bb0230a72f65e48 commit 61df7b82820494368bd46071ca97e43a3dfc3b11 upstream. The current security_inode_setxattr() and security_inode_removexattr() hooks rely on individual LSMs to either call into the associated capability hooks (cap_inode_setxattr() or cap_inode_removexattr()), or return a magic value of 1 to indicate that the LSM layer itself should perform the capability checks. Unfortunately, with the default return value for these LSM hooks being 0, an individual LSM hook returning a 1 will cause the LSM hook processing to exit early, potentially skipping a LSM. Thankfully, with the exception of the BPF LSM, none of the LSMs which currently register inode xattr hooks should end up returning a value of 1, and in the BPF LSM case, with the BPF LSM hooks executing last there should be no real harm in stopping processing of the LSM hooks. However, the reliance on the individual LSMs to either call the capability hooks themselves, or signal the LSM with a return value of 1, is fragile and relies on a specific set of LSMs being enabled. This patch is an effort to resolve, or minimize, these issues. Before we discuss the solution, there are a few observations and considerations that we need to take into account: * BPF LSM registers an implementation for every LSM hook, and that implementation simply returns the hook's default return value, a 0 in this case. We want to ensure that the default BPF LSM behavior results in the capability checks being called. * SELinux and Smack do not expect the traditional capability checks to be applied to the xattrs that they "own". * SELinux and Smack are currently written in such a way that the xattr capability checks happen before any additional LSM specific access control checks. SELinux does apply SELinux specific access controls to all xattrs, even those not "owned" by SELinux. * IMA and EVM also register xattr hooks but assume that the LSM layer and specific LSMs have already authorized the basic xattr operation. In order to ensure we perform the capability based access controls before the individual LSM access controls, perform only one capability access control check for each operation, and clarify the logic around applying the capability controls, we need a mechanism to determine if any of the enabled LSMs "own" a particular xattr and want to take responsibility for controlling access to that xattr. The solution in this patch is to create a new LSM hook, 'inode_xattr_skipcap', that is not exported to the rest of the kernel via a security_XXX() function, but is used by the LSM layer to determine if a LSM wants to control access to a given xattr and avoid the traditional capability controls. Registering an inode_xattr_skipcap hook is optional, if a LSM declines to register an implementation, or uses an implementation that simply returns the default value (0), there is no effect as the LSM continues to enforce the capability based controls (unless another LSM takes ownership of the xattr). If none of the LSMs signal that the capability checks should be skipped, the capability check is performed and if access is granted the individual LSM xattr access control hooks are executed, keeping with the DAC-before-LSM convention. Cc: stable@vger.kernel.org Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 61df7b82820494368bd46071ca97e43a3dfc3b11 upstream.

The current security_inode_setxattr() and security_inode_removexattr()
hooks rely on individual LSMs to either call into the associated
capability hooks (cap_inode_setxattr() or cap_inode_removexattr()), or
return a magic value of 1 to indicate that the LSM layer itself should
perform the capability checks.  Unfortunately, with the default return
value for these LSM hooks being 0, an individual LSM hook returning a
1 will cause the LSM hook processing to exit early, potentially
skipping a LSM.  Thankfully, with the exception of the BPF LSM, none
of the LSMs which currently register inode xattr hooks should end up
returning a value of 1, and in the BPF LSM case, with the BPF LSM hooks
executing last there should be no real harm in stopping processing of
the LSM hooks.  However, the reliance on the individual LSMs to either
call the capability hooks themselves, or signal the LSM with a return
value of 1, is fragile and relies on a specific set of LSMs being
enabled.  This patch is an effort to resolve, or minimize, these
issues.

Before we discuss the solution, there are a few observations and
considerations that we need to take into account:
* BPF LSM registers an implementation for every LSM hook, and that
  implementation simply returns the hook's default return value, a
  0 in this case.  We want to ensure that the default BPF LSM behavior
  results in the capability checks being called.
* SELinux and Smack do not expect the traditional capability checks
  to be applied to the xattrs that they "own".
* SELinux and Smack are currently written in such a way that the
  xattr capability checks happen before any additional LSM specific
  access control checks.  SELinux does apply SELinux specific access
  controls to all xattrs, even those not "owned" by SELinux.
* IMA and EVM also register xattr hooks but assume that the LSM layer
  and specific LSMs have already authorized the basic xattr operation.

In order to ensure we perform the capability based access controls
before the individual LSM access controls, perform only one capability
access control check for each operation, and clarify the logic around
applying the capability controls, we need a mechanism to determine if
any of the enabled LSMs "own" a particular xattr and want to take
responsibility for controlling access to that xattr.  The solution in
this patch is to create a new LSM hook, 'inode_xattr_skipcap', that is
not exported to the rest of the kernel via a security_XXX() function,
but is used by the LSM layer to determine if a LSM wants to control
access to a given xattr and avoid the traditional capability controls.
Registering an inode_xattr_skipcap hook is optional, if a LSM declines
to register an implementation, or uses an implementation that simply
returns the default value (0), there is no effect as the LSM continues
to enforce the capability based controls (unless another LSM takes
ownership of the xattr).  If none of the LSMs signal that the
capability checks should be skipped, the capability check is performed
and if access is granted the individual LSM xattr access control hooks
are executed, keeping with the DAC-before-LSM convention.

Cc: stable@vger.kernel.org
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ima: Avoid blocking in RCU read-side critical section 2024-06-13T18:26:50+00:00 GUO Zihua guozihua@huawei.com 2024-05-07T01:25:41+00:00 9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 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 <guozihua@huawei.com> Acked-by: John Johansen <john.johansen@canonical.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> [PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case] Signed-off-by: Paul Moore <paul@paul-moore.com> 
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 <guozihua@huawei.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Merge tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2024-05-15T15:43:02+00:00 Linus Torvalds torvalds@linux-foundation.org 2024-05-15T15:43:02+00:00 353ad6c0839431146fdee3ff16f9dd17a2809ee4 Pull integrity updates from Mimi Zohar: "Two IMA changes, one EVM change, a use after free bug fix, and a code cleanup to address "-Wflex-array-member-not-at-end" warnings: - The existing IMA {ascii, binary}_runtime_measurements lists include a hard coded SHA1 hash. To address this limitation, define per TPM enabled hash algorithm {ascii, binary}_runtime_measurements lists - Close an IMA integrity init_module syscall measurement gap by defining a new critical-data record - Enable (partial) EVM support on stacked filesystems (overlayfs). Only EVM portable & immutable file signatures are copied up, since they do not contain filesystem specific metadata" * tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: ima: add crypto agility support for template-hash algorithm evm: Rename is_unsupported_fs to is_unsupported_hmac_fs fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509 ima: re-evaluate file integrity on file metadata change evm: Store and detect metadata inode attributes changes ima: Move file-change detection variables into new structure evm: Use the metadata inode to calculate metadata hash evm: Implement per signature type decision in security_inode_copy_up_xattr security: allow finer granularity in permitting copy-up of security xattrs ima: Rename backing_inode to real_inode integrity: Avoid -Wflex-array-member-not-at-end warnings ima: define an init_module critical data record ima: Fix use-after-free on a dentry's dname.name 
Pull integrity updates from Mimi Zohar:
 "Two IMA changes, one EVM change, a use after free bug fix, and a code
  cleanup to address "-Wflex-array-member-not-at-end" warnings:

   - The existing IMA {ascii, binary}_runtime_measurements lists include
     a hard coded SHA1 hash. To address this limitation, define per TPM
     enabled hash algorithm {ascii, binary}_runtime_measurements lists

   - Close an IMA integrity init_module syscall measurement gap by
     defining a new critical-data record

   - Enable (partial) EVM support on stacked filesystems (overlayfs).
     Only EVM portable & immutable file signatures are copied up, since
     they do not contain filesystem specific metadata"

* tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: add crypto agility support for template-hash algorithm
  evm: Rename is_unsupported_fs to is_unsupported_hmac_fs
  fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED
  evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509
  ima: re-evaluate file integrity on file metadata change
  evm: Store and detect metadata inode attributes changes
  ima: Move file-change detection variables into new structure
  evm: Use the metadata inode to calculate metadata hash
  evm: Implement per signature type decision in security_inode_copy_up_xattr
  security: allow finer granularity in permitting copy-up of security xattrs
  ima: Rename backing_inode to real_inode
  integrity: Avoid -Wflex-array-member-not-at-end warnings
  ima: define an init_module critical data record
  ima: Fix use-after-free on a dentry's dname.name
netlabel: fix RCU annotation for IPv4 options on socket creation 2024-05-13T21:58:12+00:00 Davide Caratti dcaratti@redhat.com 2024-05-10T17:19:12+00:00 8ec9897ec2e93a412b9e3119e3137583a85969e0 Xiumei reports the following splat when netlabel and TCP socket are used: ============================= WARNING: suspicious RCU usage 6.9.0-rc2+ #637 Not tainted ----------------------------- net/ipv4/cipso_ipv4.c:1880 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by ncat/23333: #0: ffffffff906030c0 (rcu_read_lock){....}-{1:2}, at: netlbl_sock_setattr+0x25/0x1b0 stack backtrace: CPU: 11 PID: 23333 Comm: ncat Kdump: loaded Not tainted 6.9.0-rc2+ #637 Hardware name: Supermicro SYS-6027R-72RF/X9DRH-7TF/7F/iTF/iF, BIOS 3.0 07/26/2013 Call Trace: <TASK> dump_stack_lvl+0xa9/0xc0 lockdep_rcu_suspicious+0x117/0x190 cipso_v4_sock_setattr+0x1ab/0x1b0 netlbl_sock_setattr+0x13e/0x1b0 selinux_netlbl_socket_post_create+0x3f/0x80 selinux_socket_post_create+0x1a0/0x460 security_socket_post_create+0x42/0x60 __sock_create+0x342/0x3a0 __sys_socket_create.part.22+0x42/0x70 __sys_socket+0x37/0xb0 __x64_sys_socket+0x16/0x20 do_syscall_64+0x96/0x180 ? do_user_addr_fault+0x68d/0xa30 ? exc_page_fault+0x171/0x280 ? asm_exc_page_fault+0x22/0x30 entry_SYSCALL_64_after_hwframe+0x71/0x79 RIP: 0033:0x7fbc0ca3fc1b Code: 73 01 c3 48 8b 0d 05 f2 1b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d d5 f1 1b 00 f7 d8 64 89 01 48 RSP: 002b:00007fff18635208 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fbc0ca3fc1b RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002 RBP: 000055d24f80f8a0 R08: 0000000000000003 R09: 0000000000000001 R10: 0000000000020000 R11: 0000000000000246 R12: 000055d24f80f8a0 R13: 0000000000000000 R14: 000055d24f80fb88 R15: 0000000000000000 </TASK> The current implementation of cipso_v4_sock_setattr() replaces IP options under the assumption that the caller holds the socket lock; however, such assumption is not true, nor needed, in selinux_socket_post_create() hook. Let all callers of cipso_v4_sock_setattr() specify the "socket lock held" condition, except selinux_socket_post_create() _ where such condition can safely be set as true even without holding the socket lock. Fixes: f6d8bd051c39 ("inet: add RCU protection to inet->opt") Reported-by: Xiumei Mu <xmu@redhat.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/r/f4260d000a3a55b9e8b6a3b4e3fffc7da9f82d41.1715359817.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Xiumei reports the following splat when netlabel and TCP socket are used:

 =============================
 WARNING: suspicious RCU usage
 6.9.0-rc2+ #637 Not tainted
 -----------------------------
 net/ipv4/cipso_ipv4.c:1880 suspicious rcu_dereference_protected() usage!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 1 lock held by ncat/23333:
  #0: ffffffff906030c0 (rcu_read_lock){....}-{1:2}, at: netlbl_sock_setattr+0x25/0x1b0

 stack backtrace:
 CPU: 11 PID: 23333 Comm: ncat Kdump: loaded Not tainted 6.9.0-rc2+ #637
 Hardware name: Supermicro SYS-6027R-72RF/X9DRH-7TF/7F/iTF/iF, BIOS 3.0  07/26/2013
 Call Trace:
  <TASK>
  dump_stack_lvl+0xa9/0xc0
  lockdep_rcu_suspicious+0x117/0x190
  cipso_v4_sock_setattr+0x1ab/0x1b0
  netlbl_sock_setattr+0x13e/0x1b0
  selinux_netlbl_socket_post_create+0x3f/0x80
  selinux_socket_post_create+0x1a0/0x460
  security_socket_post_create+0x42/0x60
  __sock_create+0x342/0x3a0
  __sys_socket_create.part.22+0x42/0x70
  __sys_socket+0x37/0xb0
  __x64_sys_socket+0x16/0x20
  do_syscall_64+0x96/0x180
  ? do_user_addr_fault+0x68d/0xa30
  ? exc_page_fault+0x171/0x280
  ? asm_exc_page_fault+0x22/0x30
  entry_SYSCALL_64_after_hwframe+0x71/0x79
 RIP: 0033:0x7fbc0ca3fc1b
 Code: 73 01 c3 48 8b 0d 05 f2 1b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d d5 f1 1b 00 f7 d8 64 89 01 48
 RSP: 002b:00007fff18635208 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fbc0ca3fc1b
 RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002
 RBP: 000055d24f80f8a0 R08: 0000000000000003 R09: 0000000000000001

R10: 0000000000020000 R11: 0000000000000246 R12: 000055d24f80f8a0
 R13: 0000000000000000 R14: 000055d24f80fb88 R15: 0000000000000000
  </TASK>

The current implementation of cipso_v4_sock_setattr() replaces IP options
under the assumption that the caller holds the socket lock; however, such
assumption is not true, nor needed, in selinux_socket_post_create() hook.

Let all callers of cipso_v4_sock_setattr() specify the "socket lock held"
condition, except selinux_socket_post_create() _ where such condition can
safely be set as true even without holding the socket lock.

Fixes: f6d8bd051c39 ("inet: add RCU protection to inet->opt")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/f4260d000a3a55b9e8b6a3b4e3fffc7da9f82d41.1715359817.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>