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2021-06-10LSM: SafeSetID: Mark safesetid_initialized as __initdataAustin Kim1-1/+1
Mark safesetid_initialized as __initdata since it is only used in initialization routine. Signed-off-by: Austin Kim <austindh.kim@gmail.com> Signed-off-by: Micah Morton <mortonm@chromium.org>
2020-10-13LSM: SafeSetID: Add GID security policy handlingThomas Cedeno1-9/+29
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: add read handlerJann Horn1-0/+1
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>
2019-07-15LSM: SafeSetID: rewrite userspace API to atomic updatesJann Horn1-12/+12
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 policy hash tableJann Horn1-0/+19
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>
2019-01-25LSM: add SafeSetID module that gates setid callsMicah Morton1-0/+33
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>