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path: root/security/safesetid/lsm.c
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2020-10-13LSM: SafeSetID: Fix warnings reported by test botThomas Cedeno
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>
2020-10-13LSM: SafeSetID: Add GID security policy handlingThomas Cedeno
The SafeSetID LSM has functionality for restricting setuid() calls based on its configured security policies. This patch adds the analogous functionality for setgid() calls. This is mostly a copy-and-paste change with some code deduplication, plus slight modifications/name changes to the policy-rule-related structs (now contain GID rules in addition to the UID ones) and some type generalization since SafeSetID now needs to deal with kgid_t and kuid_t types. Signed-off-by: Thomas Cedeno <thomascedeno@google.com> Signed-off-by: Micah Morton <mortonm@chromium.org>
2019-07-15LSM: SafeSetID: fix use of literal -1 in capable hookJann Horn
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>
2019-07-15LSM: SafeSetID: rewrite userspace API to atomic updatesJann Horn
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>
2019-07-15LSM: SafeSetID: refactor safesetid_security_capable()Jann Horn
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>
2019-07-15LSM: SafeSetID: refactor policy hash tableJann Horn
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>
2019-07-15LSM: SafeSetID: fix check for setresuid(new1, new2, new3)Jann Horn
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>
2019-07-15LSM: SafeSetID: fix pr_warn() to include newlineJann Horn
Fix the pr_warn() calls in the SafeSetID LSM to have newlines at the end. Without this, denial messages will be buffered as incomplete lines in log_output(), and will then only show up once something else prints into dmesg. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Micah Morton <mortonm@chromium.org>
2019-05-27signal: Remove task parameter from force_sigEric W. Biederman
All of the remaining callers pass current into force_sig so remove the task parameter to make this obvious and to make misuse more difficult in the future. This also makes it clear force_sig passes current into force_sig_info. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2019-01-30LSM: SafeSetID: remove unused includeMicah Morton
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>
2019-01-28LSM: Add 'name' field for SafeSetID in DEFINE_LSMMicah Morton
Without this, system boot was crashing with: [0.174285] LSM: Security Framework initializing [0.175277] BUG: unable to handle kernel NULL pointer dereference ... [0.176272] Call Trace: [0.176272] ordered_lsm_parse+0x112/0x20b [0.176272] security_init+0x9b/0x3ab [0.176272] start_kernel+0x413/0x479 [0.176272] secondary_startup_64+0xa4/0xb0 Signed-off-by: Micah Morton <mortonm@chromium.org> Fixed-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2019-01-25LSM: add SafeSetID module that gates setid callsMicah Morton
SafeSetID gates the setid family of syscalls to restrict UID/GID transitions from a given UID/GID to only those approved by a system-wide whitelist. These restrictions also prohibit the given UIDs/GIDs from obtaining auxiliary privileges associated with CAP_SET{U/G}ID, such as allowing a user to set up user namespace UID mappings. For now, only gating the set*uid family of syscalls is supported, with support for set*gid coming in a future patch set. Signed-off-by: Micah Morton <mortonm@chromium.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.morris@microsoft.com>