| 03ca0ec1 | 11-Aug-2020 |
Thomas Cedeno <thomascedeno@google.com> |
LSM: SafeSetID: Fix warnings reported by test bot
Fix multiple cast-to-union warnings related to casting kuid_t and kgid_t
types to kid_t union type. Also fix incompatible type warning that
arises f
LSM: SafeSetID: Fix warnings reported by test bot
Fix multiple cast-to-union warnings related to casting kuid_t and kgid_t
types to kid_t union type. Also fix incompatible type warning that
arises from accidental omission of "__rcu" qualifier on the struct
setid_ruleset pointer in the argument list for safesetid_file_read().
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Cedeno <thomascedeno@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| e10337da | 10-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: fix use of literal -1 in capable hook
The capable() hook returns an error number. -EPERM is actually the same as
-1, so this doesn't make a difference in behavior.
Signed-off-by: Ja
LSM: SafeSetID: fix use of literal -1 in capable hook
The capable() hook returns an error number. -EPERM is actually the same as
-1, so this doesn't make a difference in behavior.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| 4f72123d | 11-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: verify transitive constrainedness
Someone might write a ruleset like the following, expecting that it
securely constrains UID 1 to UIDs 1, 2 and 3:
1:2
1:3
However, because
LSM: SafeSetID: verify transitive constrainedness
Someone might write a ruleset like the following, expecting that it
securely constrains UID 1 to UIDs 1, 2 and 3:
1:2
1:3
However, because no constraints are applied to UIDs 2 and 3, an attacker
with UID 1 can simply first switch to UID 2, then switch to any UID from
there. The secure way to write this ruleset would be:
1:2
1:3
2:2
3:3
, which uses "transition to self" as a way to inhibit the default-allow
policy without allowing anything specific.
This is somewhat unintuitive. To make sure that policy authors don't
accidentally write insecure policies because of this, let the kernel verify
that a new ruleset does not contain any entries that are constrained, but
transitively unconstrained.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| fbd9acb2 | 11-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: add read handler
For debugging a running system, it is very helpful to be able to see what
policy the system is using. Add a read handler that can dump out a copy of
the loaded polic
LSM: SafeSetID: add read handler
For debugging a running system, it is very helpful to be able to see what
policy the system is using. Add a read handler that can dump out a copy of
the loaded policy.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| 03638e62 | 10-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: rewrite userspace API to atomic updates
The current API of the SafeSetID LSM uses one write() per rule, and applies
each written rule instantly. This has several downsides:
- While
LSM: SafeSetID: rewrite userspace API to atomic updates
The current API of the SafeSetID LSM uses one write() per rule, and applies
each written rule instantly. This has several downsides:
- While a policy is being loaded, once a single parent-child pair has been
loaded, the parent is restricted to that specific child, even if
subsequent rules would allow transitions to other child UIDs. This means
that during policy loading, set*uid() can randomly fail.
- To replace the policy without rebooting, it is necessary to first flush
all old rules. This creates a time window in which no constraints are
placed on the use of CAP_SETUID.
- If we want to perform sanity checks on the final policy, this requires
that the policy isn't constructed in a piecemeal fashion without telling
the kernel when it's done.
Other kernel APIs - including things like the userns code and netfilter -
avoid this problem by performing updates atomically. Luckily, SafeSetID
hasn't landed in a stable (upstream) release yet, so maybe it's not too
late to completely change the API.
The new API for SafeSetID is: If you want to change the policy, open
"safesetid/whitelist_policy" and write the entire policy,
newline-delimited, in there.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| 71a98971 | 10-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: fix userns handling in securityfs
Looking at current_cred() in write handlers is bad form, stop doing that.
Also, let's just require that the write is coming from the initial user
n
LSM: SafeSetID: fix userns handling in securityfs
Looking at current_cred() in write handlers is bad form, stop doing that.
Also, let's just require that the write is coming from the initial user
namespace. Especially SAFESETID_WHITELIST_FLUSH requires privilege over all
namespaces, and SAFESETID_WHITELIST_ADD should probably require it as well.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| 78ae7df9 | 10-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: refactor policy parsing
In preparation for changing the policy parsing logic, refactor the line
parsing logic to be less verbose and move it into a separate function.
Signed-off-by:
LSM: SafeSetID: refactor policy parsing
In preparation for changing the policy parsing logic, refactor the line
parsing logic to be less verbose and move it into a separate function.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| 8068866c | 10-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: refactor safesetid_security_capable()
At the moment, safesetid_security_capable() has two nested conditional
blocks, and one big comment for all the logic. Chop it up and reduce the
LSM: SafeSetID: refactor safesetid_security_capable()
At the moment, safesetid_security_capable() has two nested conditional
blocks, and one big comment for all the logic. Chop it up and reduce the
amount of indentation.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| 1cd02a27 | 10-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: refactor policy hash table
parent_kuid and child_kuid are kuids, there is no reason to make them
uint64_t. (And anyway, in the kernel, the normal name for that would be
u64, not uint
LSM: SafeSetID: refactor policy hash table
parent_kuid and child_kuid are kuids, there is no reason to make them
uint64_t. (And anyway, in the kernel, the normal name for that would be
u64, not uint64_t.)
check_setuid_policy_hashtable_key() and
check_setuid_policy_hashtable_key_value() are basically the same thing,
merge them.
Also fix the comment that claimed that (1<<8)==128.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| 7ef6b306 | 10-Apr-2019 |
Jann Horn <jannh@google.com> |
LSM: SafeSetID: fix check for setresuid(new1, new2, new3)
With the old code, when a process with the (real,effective,saved) UID set
(1,1,1) calls setresuid(2,3,4), safesetid_task_fix_setuid() only c
LSM: SafeSetID: fix check for setresuid(new1, new2, new3)
With the old code, when a process with the (real,effective,saved) UID set
(1,1,1) calls setresuid(2,3,4), safesetid_task_fix_setuid() only checks
whether the transition 1->2 is permitted; the transitions 1->3 and 1->4 are
not checked. Fix this.
This is also a good opportunity to refactor safesetid_task_fix_setuid() to
be less verbose - having one branch per set*uid() syscall is unnecessary.
Note that this slightly changes semantics: The UID transition check for
UIDs that were not in the old cred struct is now always performed against
the policy of the RUID. I think that's more consistent anyway, since the
RUID is also the one that decides whether any policy is enforced at all.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
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| e7a44cfd | 12-Feb-2019 |
Wei Yongjun <weiyongjun1@huawei.com> |
LSM: fix return value check in safesetid_init_securityfs()
In case of error, the function securityfs_create_dir() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check sh
LSM: fix return value check in safesetid_init_securityfs()
In case of error, the function securityfs_create_dir() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().
Fixes: aeca4e2ca65c ("LSM: add SafeSetID module that gates setid calls")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>
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| 2181e084 | 30-Jan-2019 |
Micah Morton <mortonm@chromium.org> |
LSM: SafeSetID: remove unused include
The include for asm/syscall.h was needed in a prior version of lsm.c
that checked return values of syscall_get_nr, but since we did away with
that part of the c
LSM: SafeSetID: remove unused include
The include for asm/syscall.h was needed in a prior version of lsm.c
that checked return values of syscall_get_nr, but since we did away with
that part of the code this include is no longer necessary. Take out this
include since it breaks builds for certain architectures. We no longer
have any arch-specific code in SafeSetID.
Signed-off-by: Micah Morton <mortonm@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>
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| 2f87324b | 29-Jan-2019 |
Micah Morton <mortonm@chromium.org> |
LSM: SafeSetID: 'depend' on CONFIG_SECURITY
This patch changes the Kconfig file for the SafeSetID LSM to depend on
CONFIG_SECURITY as well as select CONFIG_SECURITYFS, since the policies
for the LSM
LSM: SafeSetID: 'depend' on CONFIG_SECURITY
This patch changes the Kconfig file for the SafeSetID LSM to depend on
CONFIG_SECURITY as well as select CONFIG_SECURITYFS, since the policies
for the LSM are configured through writing to securityfs.
Signed-off-by: Micah Morton <mortonm@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>
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