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authorLinus Torvalds <torvalds@linux-foundation.org>2024-09-16 18:19:47 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2024-09-16 18:19:47 +0200
commita430d95c5efa2b545d26a094eb5f624e36732af0 (patch)
treedf11f0f881c3959da82d9de5fa5310466255ff42 /security/security.c
parentad060dbbcfcfcba624ef1a75e1d71365a98b86d8 (diff)
parent19c9d55d72a9040cf9dc8de62633e6217381106b (diff)
Merge tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm
Pull lsm updates from Paul Moore: - Move the LSM framework to static calls This transitions the vast majority of the LSM callbacks into static calls. Those callbacks which haven't been converted were left as-is due to the general ugliness of the changes required to support the static call conversion; we can revisit those callbacks at a future date. - Add the Integrity Policy Enforcement (IPE) LSM This adds a new LSM, Integrity Policy Enforcement (IPE). There is plenty of documentation about IPE in this patches, so I'll refrain from going into too much detail here, but the basic motivation behind IPE is to provide a mechanism such that administrators can restrict execution to only those binaries which come from integrity protected storage, e.g. a dm-verity protected filesystem. You will notice that IPE requires additional LSM hooks in the initramfs, dm-verity, and fs-verity code, with the associated patches carrying ACK/review tags from the associated maintainers. We couldn't find an obvious maintainer for the initramfs code, but the IPE patchset has been widely posted over several years. Both Deven Bowers and Fan Wu have contributed to IPE's development over the past several years, with Fan Wu agreeing to serve as the IPE maintainer moving forward. Once IPE is accepted into your tree, I'll start working with Fan to ensure he has the necessary accounts, keys, etc. so that he can start submitting IPE pull requests to you directly during the next merge window. - Move the lifecycle management of the LSM blobs to the LSM framework Management of the LSM blobs (the LSM state buffers attached to various kernel structs, typically via a void pointer named "security" or similar) has been mixed, some blobs were allocated/managed by individual LSMs, others were managed by the LSM framework itself. Starting with this pull we move management of all the LSM blobs, minus the XFRM blob, into the framework itself, improving consistency across LSMs, and reducing the amount of duplicated code across LSMs. Due to some additional work required to migrate the XFRM blob, it has been left as a todo item for a later date; from a practical standpoint this omission should have little impact as only SELinux provides a XFRM LSM implementation. - Fix problems with the LSM's handling of F_SETOWN The LSM hook for the fcntl(F_SETOWN) operation had a couple of problems: it was racy with itself, and it was disconnected from the associated DAC related logic in such a way that the LSM state could be updated in cases where the DAC state would not. We fix both of these problems by moving the security_file_set_fowner() hook into the same section of code where the DAC attributes are updated. Not only does this resolve the DAC/LSM synchronization issue, but as that code block is protected by a lock, it also resolve the race condition. - Fix potential problems with the security_inode_free() LSM hook Due to use of RCU to protect inodes and the placement of the LSM hook associated with freeing the inode, there is a bit of a challenge when it comes to managing any LSM state associated with an inode. The VFS folks are not open to relocating the LSM hook so we have to get creative when it comes to releasing an inode's LSM state. Traditionally we have used a single LSM callback within the hook that is triggered when the inode is "marked for death", but not actually released due to RCU. Unfortunately, this causes problems for LSMs which want to take an action when the inode's associated LSM state is actually released; so we add an additional LSM callback, inode_free_security_rcu(), that is called when the inode's LSM state is released in the RCU free callback. - Refactor two LSM hooks to better fit the LSM return value patterns The vast majority of the LSM hooks follow the "return 0 on success, negative values on failure" pattern, however, there are a small handful that have unique return value behaviors which has caused confusion in the past and makes it difficult for the BPF verifier to properly vet BPF LSM programs. This includes patches to convert two of these"special" LSM hooks to the common 0/-ERRNO pattern. - Various cleanups and improvements A handful of patches to remove redundant code, better leverage the IS_ERR_OR_NULL() helper, add missing "static" markings, and do some minor style fixups. * tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (40 commits) security: Update file_set_fowner documentation fs: Fix file_set_fowner LSM hook inconsistencies lsm: Use IS_ERR_OR_NULL() helper function lsm: remove LSM_COUNT and LSM_CONFIG_COUNT ipe: Remove duplicated include in ipe.c lsm: replace indirect LSM hook calls with static calls lsm: count the LSMs enabled at compile time kernel: Add helper macros for loop unrolling init/main.c: Initialize early LSMs after arch code, static keys and calls. MAINTAINERS: add IPE entry with Fan Wu as maintainer documentation: add IPE documentation ipe: kunit test for parser scripts: add boot policy generation program ipe: enable support for fs-verity as a trust provider fsverity: expose verified fsverity built-in signatures to LSMs lsm: add security_inode_setintegrity() hook ipe: add support for dm-verity as a trust provider dm-verity: expose root hash digest and signature data to LSMs block,lsm: add LSM blob and new LSM hooks for block devices ipe: add permissive toggle ...
Diffstat (limited to 'security/security.c')
-rw-r--r--security/security.c613
1 files changed, 443 insertions, 170 deletions
diff --git a/security/security.c b/security/security.c
index 8cee5b6c6e6d..4564a0a1e4ef 100644
--- a/security/security.c
+++ b/security/security.c
@@ -28,30 +28,29 @@
#include <linux/xattr.h>
#include <linux/msg.h>
#include <linux/overflow.h>
+#include <linux/perf_event.h>
+#include <linux/fs.h>
#include <net/flow.h>
+#include <net/sock.h>
-/* How many LSMs were built into the kernel? */
-#define LSM_COUNT (__end_lsm_info - __start_lsm_info)
+#define SECURITY_HOOK_ACTIVE_KEY(HOOK, IDX) security_hook_active_##HOOK##_##IDX
/*
- * How many LSMs are built into the kernel as determined at
- * build time. Used to determine fixed array sizes.
- * The capability module is accounted for by CONFIG_SECURITY
- */
-#define LSM_CONFIG_COUNT ( \
- (IS_ENABLED(CONFIG_SECURITY) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_TOMOYO) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_YAMA) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_LOADPIN) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_SAFESETID) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_IMA) ? 1 : 0) + \
- (IS_ENABLED(CONFIG_EVM) ? 1 : 0))
+ * Identifier for the LSM static calls.
+ * HOOK is an LSM hook as defined in linux/lsm_hookdefs.h
+ * IDX is the index of the static call. 0 <= NUM < MAX_LSM_COUNT
+ */
+#define LSM_STATIC_CALL(HOOK, IDX) lsm_static_call_##HOOK##_##IDX
+
+/*
+ * Call the macro M for each LSM hook MAX_LSM_COUNT times.
+ */
+#define LSM_LOOP_UNROLL(M, ...) \
+do { \
+ UNROLL(MAX_LSM_COUNT, M, __VA_ARGS__) \
+} while (0)
+
+#define LSM_DEFINE_UNROLL(M, ...) UNROLL(MAX_LSM_COUNT, M, __VA_ARGS__)
/*
* These are descriptions of the reasons that can be passed to the
@@ -92,7 +91,6 @@ const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX + 1] = {
[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
};
-struct security_hook_heads security_hook_heads __ro_after_init;
static BLOCKING_NOTIFIER_HEAD(blocking_lsm_notifier_chain);
static struct kmem_cache *lsm_file_cache;
@@ -108,9 +106,58 @@ static __initdata const char *chosen_major_lsm;
static __initconst const char *const builtin_lsm_order = CONFIG_LSM;
/* Ordered list of LSMs to initialize. */
-static __initdata struct lsm_info **ordered_lsms;
+static __initdata struct lsm_info *ordered_lsms[MAX_LSM_COUNT + 1];
static __initdata struct lsm_info *exclusive;
+#ifdef CONFIG_HAVE_STATIC_CALL
+#define LSM_HOOK_TRAMP(NAME, NUM) \
+ &STATIC_CALL_TRAMP(LSM_STATIC_CALL(NAME, NUM))
+#else
+#define LSM_HOOK_TRAMP(NAME, NUM) NULL
+#endif
+
+/*
+ * Define static calls and static keys for each LSM hook.
+ */
+#define DEFINE_LSM_STATIC_CALL(NUM, NAME, RET, ...) \
+ DEFINE_STATIC_CALL_NULL(LSM_STATIC_CALL(NAME, NUM), \
+ *((RET(*)(__VA_ARGS__))NULL)); \
+ DEFINE_STATIC_KEY_FALSE(SECURITY_HOOK_ACTIVE_KEY(NAME, NUM));
+
+#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
+ LSM_DEFINE_UNROLL(DEFINE_LSM_STATIC_CALL, NAME, RET, __VA_ARGS__)
+#include <linux/lsm_hook_defs.h>
+#undef LSM_HOOK
+#undef DEFINE_LSM_STATIC_CALL
+
+/*
+ * Initialise a table of static calls for each LSM hook.
+ * DEFINE_STATIC_CALL_NULL invocation above generates a key (STATIC_CALL_KEY)
+ * and a trampoline (STATIC_CALL_TRAMP) which are used to call
+ * __static_call_update when updating the static call.
+ *
+ * The static calls table is used by early LSMs, some architectures can fault on
+ * unaligned accesses and the fault handling code may not be ready by then.
+ * Thus, the static calls table should be aligned to avoid any unhandled faults
+ * in early init.
+ */
+struct lsm_static_calls_table
+ static_calls_table __ro_after_init __aligned(sizeof(u64)) = {
+#define INIT_LSM_STATIC_CALL(NUM, NAME) \
+ (struct lsm_static_call) { \
+ .key = &STATIC_CALL_KEY(LSM_STATIC_CALL(NAME, NUM)), \
+ .trampoline = LSM_HOOK_TRAMP(NAME, NUM), \
+ .active = &SECURITY_HOOK_ACTIVE_KEY(NAME, NUM), \
+ },
+#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
+ .NAME = { \
+ LSM_DEFINE_UNROLL(INIT_LSM_STATIC_CALL, NAME) \
+ },
+#include <linux/lsm_hook_defs.h>
+#undef LSM_HOOK
+#undef INIT_LSM_STATIC_CALL
+ };
+
static __initdata bool debug;
#define init_debug(...) \
do { \
@@ -171,7 +218,7 @@ static void __init append_ordered_lsm(struct lsm_info *lsm, const char *from)
if (exists_ordered_lsm(lsm))
return;
- if (WARN(last_lsm == LSM_COUNT, "%s: out of LSM slots!?\n", from))
+ if (WARN(last_lsm == MAX_LSM_COUNT, "%s: out of LSM static calls!?\n", from))
return;
/* Enable this LSM, if it is not already set. */
@@ -218,6 +265,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
lsm_set_blob_size(&needed->lbs_cred, &blob_sizes.lbs_cred);
lsm_set_blob_size(&needed->lbs_file, &blob_sizes.lbs_file);
+ lsm_set_blob_size(&needed->lbs_ib, &blob_sizes.lbs_ib);
/*
* The inode blob gets an rcu_head in addition to
* what the modules might need.
@@ -226,11 +274,16 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
blob_sizes.lbs_inode = sizeof(struct rcu_head);
lsm_set_blob_size(&needed->lbs_inode, &blob_sizes.lbs_inode);
lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc);
+ lsm_set_blob_size(&needed->lbs_key, &blob_sizes.lbs_key);
lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg);
+ lsm_set_blob_size(&needed->lbs_perf_event, &blob_sizes.lbs_perf_event);
+ lsm_set_blob_size(&needed->lbs_sock, &blob_sizes.lbs_sock);
lsm_set_blob_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock);
lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task);
+ lsm_set_blob_size(&needed->lbs_tun_dev, &blob_sizes.lbs_tun_dev);
lsm_set_blob_size(&needed->lbs_xattr_count,
&blob_sizes.lbs_xattr_count);
+ lsm_set_blob_size(&needed->lbs_bdev, &blob_sizes.lbs_bdev);
}
/* Prepare LSM for initialization. */
@@ -268,7 +321,7 @@ static void __init initialize_lsm(struct lsm_info *lsm)
* Current index to use while initializing the lsm id list.
*/
u32 lsm_active_cnt __ro_after_init;
-const struct lsm_id *lsm_idlist[LSM_CONFIG_COUNT];
+const struct lsm_id *lsm_idlist[MAX_LSM_COUNT];
/* Populate ordered LSMs list from comma-separated LSM name list. */
static void __init ordered_lsm_parse(const char *order, const char *origin)
@@ -350,6 +403,25 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
kfree(sep);
}
+static void __init lsm_static_call_init(struct security_hook_list *hl)
+{
+ struct lsm_static_call *scall = hl->scalls;
+ int i;
+
+ for (i = 0; i < MAX_LSM_COUNT; i++) {
+ /* Update the first static call that is not used yet */
+ if (!scall->hl) {
+ __static_call_update(scall->key, scall->trampoline,
+ hl->hook.lsm_func_addr);
+ scall->hl = hl;
+ static_branch_enable(scall->active);
+ return;
+ }
+ scall++;
+ }
+ panic("%s - Ran out of static slots.\n", __func__);
+}
+
static void __init lsm_early_cred(struct cred *cred);
static void __init lsm_early_task(struct task_struct *task);
@@ -378,9 +450,6 @@ static void __init ordered_lsm_init(void)
{
struct lsm_info **lsm;
- ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms),
- GFP_KERNEL);
-
if (chosen_lsm_order) {
if (chosen_major_lsm) {
pr_warn("security=%s is ignored because it is superseded by lsm=%s\n",
@@ -398,12 +467,20 @@ static void __init ordered_lsm_init(void)
init_debug("cred blob size = %d\n", blob_sizes.lbs_cred);
init_debug("file blob size = %d\n", blob_sizes.lbs_file);
+ init_debug("ib blob size = %d\n", blob_sizes.lbs_ib);
init_debug("inode blob size = %d\n", blob_sizes.lbs_inode);
init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc);
+#ifdef CONFIG_KEYS
+ init_debug("key blob size = %d\n", blob_sizes.lbs_key);
+#endif /* CONFIG_KEYS */
init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg);
+ init_debug("sock blob size = %d\n", blob_sizes.lbs_sock);
init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
+ init_debug("perf event blob size = %d\n", blob_sizes.lbs_perf_event);
init_debug("task blob size = %d\n", blob_sizes.lbs_task);
+ init_debug("tun device blob size = %d\n", blob_sizes.lbs_tun_dev);
init_debug("xattr slots = %d\n", blob_sizes.lbs_xattr_count);
+ init_debug("bdev blob size = %d\n", blob_sizes.lbs_bdev);
/*
* Create any kmem_caches needed for blobs
@@ -421,19 +498,12 @@ static void __init ordered_lsm_init(void)
lsm_early_task(current);
for (lsm = ordered_lsms; *lsm; lsm++)
initialize_lsm(*lsm);
-
- kfree(ordered_lsms);
}
int __init early_security_init(void)
{
struct lsm_info *lsm;
-#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
- INIT_HLIST_HEAD(&security_hook_heads.NAME);
-#include "linux/lsm_hook_defs.h"
-#undef LSM_HOOK
-
for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) {
if (!lsm->enabled)
lsm->enabled = &lsm_enabled_true;
@@ -554,14 +624,14 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
* Look at the previous entry, if there is one, for duplication.
*/
if (lsm_active_cnt == 0 || lsm_idlist[lsm_active_cnt - 1] != lsmid) {
- if (lsm_active_cnt >= LSM_CONFIG_COUNT)
+ if (lsm_active_cnt >= MAX_LSM_COUNT)
panic("%s Too many LSMs registered.\n", __func__);
lsm_idlist[lsm_active_cnt++] = lsmid;
}
for (i = 0; i < count; i++) {
hooks[i].lsmid = lsmid;
- hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
+ lsm_static_call_init(&hooks[i]);
}
/*
@@ -596,28 +666,43 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb)
EXPORT_SYMBOL(unregister_blocking_lsm_notifier);
/**
- * lsm_cred_alloc - allocate a composite cred blob
- * @cred: the cred that needs a blob
+ * lsm_blob_alloc - allocate a composite blob
+ * @dest: the destination for the blob
+ * @size: the size of the blob
* @gfp: allocation type
*
- * Allocate the cred blob for all the modules
+ * Allocate a blob for all the modules
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
-static int lsm_cred_alloc(struct cred *cred, gfp_t gfp)
+static int lsm_blob_alloc(void **dest, size_t size, gfp_t gfp)
{
- if (blob_sizes.lbs_cred == 0) {
- cred->security = NULL;
+ if (size == 0) {
+ *dest = NULL;
return 0;
}
- cred->security = kzalloc(blob_sizes.lbs_cred, gfp);
- if (cred->security == NULL)
+ *dest = kzalloc(size, gfp);
+ if (*dest == NULL)
return -ENOMEM;
return 0;
}
/**
+ * lsm_cred_alloc - allocate a composite cred blob
+ * @cred: the cred that needs a blob
+ * @gfp: allocation type
+ *
+ * Allocate the cred blob for all the modules
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_cred_alloc(struct cred *cred, gfp_t gfp)
+{
+ return lsm_blob_alloc(&cred->security, blob_sizes.lbs_cred, gfp);
+}
+
+/**
* lsm_early_cred - during initialization allocate a composite cred blob
* @cred: the cred that needs a blob
*
@@ -660,7 +745,7 @@ static int lsm_file_alloc(struct file *file)
*
* Returns 0, or -ENOMEM if memory can't be allocated.
*/
-int lsm_inode_alloc(struct inode *inode)
+static int lsm_inode_alloc(struct inode *inode)
{
if (!lsm_inode_cache) {
inode->i_security = NULL;
@@ -683,15 +768,7 @@ int lsm_inode_alloc(struct inode *inode)
*/
static int lsm_task_alloc(struct task_struct *task)
{
- if (blob_sizes.lbs_task == 0) {
- task->security = NULL;
- return 0;
- }
-
- task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL);
- if (task->security == NULL)
- return -ENOMEM;
- return 0;
+ return lsm_blob_alloc(&task->security, blob_sizes.lbs_task, GFP_KERNEL);
}
/**
@@ -704,16 +781,23 @@ static int lsm_task_alloc(struct task_struct *task)
*/
static int lsm_ipc_alloc(struct kern_ipc_perm *kip)
{
- if (blob_sizes.lbs_ipc == 0) {
- kip->security = NULL;
- return 0;
- }
+ return lsm_blob_alloc(&kip->security, blob_sizes.lbs_ipc, GFP_KERNEL);
+}
- kip->security = kzalloc(blob_sizes.lbs_ipc, GFP_KERNEL);
- if (kip->security == NULL)
- return -ENOMEM;
- return 0;
+#ifdef CONFIG_KEYS
+/**
+ * lsm_key_alloc - allocate a composite key blob
+ * @key: the key that needs a blob
+ *
+ * Allocate the key blob for all the modules
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_key_alloc(struct key *key)
+{
+ return lsm_blob_alloc(&key->security, blob_sizes.lbs_key, GFP_KERNEL);
}
+#endif /* CONFIG_KEYS */
/**
* lsm_msg_msg_alloc - allocate a composite msg_msg blob
@@ -725,14 +809,29 @@ static int lsm_ipc_alloc(struct kern_ipc_perm *kip)
*/
static int lsm_msg_msg_alloc(struct msg_msg *mp)
{
- if (blob_sizes.lbs_msg_msg == 0) {
- mp->security = NULL;
+ return lsm_blob_alloc(&mp->security, blob_sizes.lbs_msg_msg,
+ GFP_KERNEL);
+}
+
+/**
+ * lsm_bdev_alloc - allocate a composite block_device blob
+ * @bdev: the block_device that needs a blob
+ *
+ * Allocate the block_device blob for all the modules
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_bdev_alloc(struct block_device *bdev)
+{
+ if (blob_sizes.lbs_bdev == 0) {
+ bdev->bd_security = NULL;
return 0;
}
- mp->security = kzalloc(blob_sizes.lbs_msg_msg, GFP_KERNEL);
- if (mp->security == NULL)
+ bdev->bd_security = kzalloc(blob_sizes.lbs_bdev, GFP_KERNEL);
+ if (!bdev->bd_security)
return -ENOMEM;
+
return 0;
}
@@ -760,15 +859,8 @@ static void __init lsm_early_task(struct task_struct *task)
*/
static int lsm_superblock_alloc(struct super_block *sb)
{
- if (blob_sizes.lbs_superblock == 0) {
- sb->s_security = NULL;
- return 0;
- }
-
- sb->s_security = kzalloc(blob_sizes.lbs_superblock, GFP_KERNEL);
- if (sb->s_security == NULL)
- return -ENOMEM;
- return 0;
+ return lsm_blob_alloc(&sb->s_security, blob_sizes.lbs_superblock,
+ GFP_KERNEL);
}
/**
@@ -853,29 +945,43 @@ out:
* call_int_hook:
* This is a hook that returns a value.
*/
+#define __CALL_STATIC_VOID(NUM, HOOK, ...) \
+do { \
+ if (static_branch_unlikely(&SECURITY_HOOK_ACTIVE_KEY(HOOK, NUM))) { \
+ static_call(LSM_STATIC_CALL(HOOK, NUM))(__VA_ARGS__); \
+ } \
+} while (0);
-#define call_void_hook(FUNC, ...) \
- do { \
- struct security_hook_list *P; \
- \
- hlist_for_each_entry(P, &security_hook_heads.FUNC, list) \
- P->hook.FUNC(__VA_ARGS__); \
+#define call_void_hook(HOOK, ...) \
+ do { \
+ LSM_LOOP_UNROLL(__CALL_STATIC_VOID, HOOK, __VA_ARGS__); \
} while (0)
-#define call_int_hook(FUNC, ...) ({ \
- int RC = LSM_RET_DEFAULT(FUNC); \
- do { \
- struct security_hook_list *P; \
- \
- hlist_for_each_entry(P, &security_hook_heads.FUNC, list) { \
- RC = P->hook.FUNC(__VA_ARGS__); \
- if (RC != LSM_RET_DEFAULT(FUNC)) \
- break; \
- } \
- } while (0); \
- RC; \
+
+#define __CALL_STATIC_INT(NUM, R, HOOK, LABEL, ...) \
+do { \
+ if (static_branch_unlikely(&SECURITY_HOOK_ACTIVE_KEY(HOOK, NUM))) { \
+ R = static_call(LSM_STATIC_CALL(HOOK, NUM))(__VA_ARGS__); \
+ if (R != LSM_RET_DEFAULT(HOOK)) \
+ goto LABEL; \
+ } \
+} while (0);
+
+#define call_int_hook(HOOK, ...) \
+({ \
+ __label__ OUT; \
+ int RC = LSM_RET_DEFAULT(HOOK); \
+ \
+ LSM_LOOP_UNROLL(__CALL_STATIC_INT, RC, HOOK, OUT, __VA_ARGS__); \
+OUT: \
+ RC; \
})
+#define lsm_for_each_hook(scall, NAME) \
+ for (scall = static_calls_table.NAME; \
+ scall - static_calls_table.NAME < MAX_LSM_COUNT; scall++) \
+ if (static_key_enabled(&scall->active->key))
+
/* Security operations */
/**
@@ -1110,20 +1216,19 @@ int security_settime64(const struct timespec64 *ts, const struct timezone *tz)
*/
int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
int cap_sys_admin = 1;
int rc;
/*
- * The module will respond with a positive value if
- * it thinks the __vm_enough_memory() call should be
- * made with the cap_sys_admin set. If all of the modules
- * agree that it should be set it will. If any module
- * thinks it should not be set it won't.
+ * The module will respond with 0 if it thinks the __vm_enough_memory()
+ * call should be made with the cap_sys_admin set. If all of the modules
+ * agree that it should be set it will. If any module thinks it should
+ * not be set it won't.
*/
- hlist_for_each_entry(hp, &security_hook_heads.vm_enough_memory, list) {
- rc = hp->hook.vm_enough_memory(mm, pages);
- if (rc <= 0) {
+ lsm_for_each_hook(scall, vm_enough_memory) {
+ rc = scall->hl->hook.vm_enough_memory(mm, pages);
+ if (rc < 0) {
cap_sys_admin = 0;
break;
}
@@ -1269,13 +1374,12 @@ int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
int security_fs_context_parse_param(struct fs_context *fc,
struct fs_parameter *param)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
int trc;
int rc = -ENOPARAM;
- hlist_for_each_entry(hp, &security_hook_heads.fs_context_parse_param,
- list) {
- trc = hp->hook.fs_context_parse_param(fc, param);
+ lsm_for_each_hook(scall, fs_context_parse_param) {
+ trc = scall->hl->hook.fs_context_parse_param(fc, param);
if (trc == 0)
rc = 0;
else if (trc != -ENOPARAM)
@@ -1505,12 +1609,11 @@ int security_sb_set_mnt_opts(struct super_block *sb,
unsigned long kern_flags,
unsigned long *set_kern_flags)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
int rc = mnt_opts ? -EOPNOTSUPP : LSM_RET_DEFAULT(sb_set_mnt_opts);
- hlist_for_each_entry(hp, &security_hook_heads.sb_set_mnt_opts,
- list) {
- rc = hp->hook.sb_set_mnt_opts(sb, mnt_opts, kern_flags,
+ lsm_for_each_hook(scall, sb_set_mnt_opts) {
+ rc = scall->hl->hook.sb_set_mnt_opts(sb, mnt_opts, kern_flags,
set_kern_flags);
if (rc != LSM_RET_DEFAULT(sb_set_mnt_opts))
break;
@@ -1596,9 +1699,8 @@ int security_inode_alloc(struct inode *inode)
static void inode_free_by_rcu(struct rcu_head *head)
{
- /*
- * The rcu head is at the start of the inode blob
- */
+ /* The rcu head is at the start of the inode blob */
+ call_void_hook(inode_free_security_rcu, head);
kmem_cache_free(lsm_inode_cache, head);
}
@@ -1606,23 +1708,24 @@ static void inode_free_by_rcu(struct rcu_head *head)
* security_inode_free() - Free an inode's LSM blob
* @inode: the inode
*
- * Deallocate the inode security structure and set @inode->i_security to NULL.
+ * Release any LSM resources associated with @inode, although due to the
+ * inode's RCU protections it is possible that the resources will not be
+ * fully released until after the current RCU grace period has elapsed.
+ *
+ * It is important for LSMs to note that despite being present in a call to
+ * security_inode_free(), @inode may still be referenced in a VFS path walk
+ * and calls to security_inode_permission() may be made during, or after,
+ * a call to security_inode_free(). For this reason the inode->i_security
+ * field is released via a call_rcu() callback and any LSMs which need to
+ * retain inode state for use in security_inode_permission() should only
+ * release that state in the inode_free_security_rcu() LSM hook callback.
*/
void security_inode_free(struct inode *inode)
{
call_void_hook(inode_free_security, inode);
- /*
- * The inode may still be referenced in a path walk and
- * a call to security_inode_permission() can be made
- * after inode_free_security() is called. Ideally, the VFS
- * wouldn't do this, but fixing that is a much harder
- * job. For now, simply free the i_security via RCU, and
- * leave the current inode->i_security pointer intact.
- * The inode will be freed after the RCU grace period too.
- */
- if (inode->i_security)
- call_rcu((struct rcu_head *)inode->i_security,
- inode_free_by_rcu);
+ if (!inode->i_security)
+ return;
+ call_rcu((struct rcu_head *)inode->i_security, inode_free_by_rcu);
}
/**
@@ -1705,7 +1808,7 @@ int security_inode_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr,
const initxattrs initxattrs, void *fs_data)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
struct xattr *new_xattrs = NULL;
int ret = -EOPNOTSUPP, xattr_count = 0;
@@ -1723,9 +1826,8 @@ int security_inode_init_security(struct inode *inode, struct inode *dir,
return -ENOMEM;
}
- hlist_for_each_entry(hp, &security_hook_heads.inode_init_security,
- list) {
- ret = hp->hook.inode_init_security(inode, dir, qstr, new_xattrs,
+ lsm_for_each_hook(scall, inode_init_security) {
+ ret = scall->hl->hook.inode_init_security(inode, dir, qstr, new_xattrs,
&xattr_count);
if (ret && ret != -EOPNOTSUPP)
goto out;
@@ -2661,19 +2763,14 @@ EXPORT_SYMBOL(security_inode_copy_up);
* lower layer to the union/overlay layer. The caller is responsible for
* reading and writing the xattrs, this hook is merely a filter.
*
- * Return: Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP
- * if the security module does not know about attribute, or a negative
- * error code to abort the copy up.
+ * Return: Returns 0 to accept the xattr, -ECANCELED to discard the xattr,
+ * -EOPNOTSUPP if the security module does not know about attribute,
+ * or a negative error code to abort the copy up.
*/
int security_inode_copy_up_xattr(struct dentry *src, const char *name)
{
int rc;
- /*
- * The implementation can return 0 (accept the xattr), 1 (discard the
- * xattr), -EOPNOTSUPP if it does not know anything about the xattr or
- * any other error code in case of an error.
- */
rc = call_int_hook(inode_copy_up_xattr, src, name);
if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr))
return rc;
@@ -2683,6 +2780,26 @@ int security_inode_copy_up_xattr(struct dentry *src, const char *name)
EXPORT_SYMBOL(security_inode_copy_up_xattr);
/**
+ * security_inode_setintegrity() - Set the inode's integrity data
+ * @inode: inode
+ * @type: type of integrity, e.g. hash digest, signature, etc
+ * @value: the integrity value
+ * @size: size of the integrity value
+ *
+ * Register a verified integrity measurement of a inode with LSMs.
+ * LSMs should free the previously saved data if @value is NULL.
+ *
+ * Return: Returns 0 on success, negative values on failure.
+ */
+int security_inode_setintegrity(const struct inode *inode,
+ enum lsm_integrity_type type, const void *value,
+ size_t size)
+{
+ return call_int_hook(inode_setintegrity, inode, type, value, size);
+}
+EXPORT_SYMBOL(security_inode_setintegrity);
+
+/**
* security_kernfs_init_security() - Init LSM context for a kernfs node
* @kn_dir: parent kernfs node
* @kn: the kernfs node to initialize
@@ -2931,6 +3048,8 @@ int security_file_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
* Save owner security information (typically from current->security) in
* file->f_security for later use by the send_sigiotask hook.
*
+ * This hook is called with file->f_owner.lock held.
+ *
* Return: Returns 0 on success.
*/
void security_file_set_fowner(struct file *file)
@@ -3557,10 +3676,10 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
{
int thisrc;
int rc = LSM_RET_DEFAULT(task_prctl);
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
- hlist_for_each_entry(hp, &security_hook_heads.task_prctl, list) {
- thisrc = hp->hook.task_prctl(option, arg2, arg3, arg4, arg5);
+ lsm_for_each_hook(scall, task_prctl) {
+ thisrc = scall->hl->hook.task_prctl(option, arg2, arg3, arg4, arg5);
if (thisrc != LSM_RET_DEFAULT(task_prctl)) {
rc = thisrc;
if (thisrc != 0)
@@ -3966,7 +4085,7 @@ EXPORT_SYMBOL(security_d_instantiate);
int security_getselfattr(unsigned int attr, struct lsm_ctx __user *uctx,
u32 __user *size, u32 flags)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
struct lsm_ctx lctx = { .id = LSM_ID_UNDEF, };
u8 __user *base = (u8 __user *)uctx;
u32 entrysize;
@@ -4004,13 +4123,13 @@ int security_getselfattr(unsigned int attr, struct lsm_ctx __user *uctx,
* In the usual case gather all the data from the LSMs.
* In the single case only get the data from the LSM specified.
*/
- hlist_for_each_entry(hp, &security_hook_heads.getselfattr, list) {
- if (single && lctx.id != hp->lsmid->id)
+ lsm_for_each_hook(scall, getselfattr) {
+ if (single && lctx.id != scall->hl->lsmid->id)
continue;
entrysize = left;
if (base)
uctx = (struct lsm_ctx __user *)(base + total);
- rc = hp->hook.getselfattr(attr, uctx, &entrysize, flags);
+ rc = scall->hl->hook.getselfattr(attr, uctx, &entrysize, flags);
if (rc == -EOPNOTSUPP) {
rc = 0;
continue;
@@ -4059,7 +4178,7 @@ int security_getselfattr(unsigned int attr, struct lsm_ctx __user *uctx,
int security_setselfattr(unsigned int attr, struct lsm_ctx __user *uctx,
u32 size, u32 flags)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
struct lsm_ctx *lctx;
int rc = LSM_RET_DEFAULT(setselfattr);
u64 required_len;
@@ -4082,9 +4201,9 @@ int security_setselfattr(unsigned int attr, struct lsm_ctx __user *uctx,
goto free_out;
}
- hlist_for_each_entry(hp, &security_hook_heads.setselfattr, list)
- if ((hp->lsmid->id) == lctx->id) {
- rc = hp->hook.setselfattr(attr, lctx, size, flags);
+ lsm_for_each_hook(scall, setselfattr)
+ if ((scall->hl->lsmid->id) == lctx->id) {
+ rc = scall->hl->hook.setselfattr(attr, lctx, size, flags);
break;
}
@@ -4107,12 +4226,12 @@ free_out:
int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
char **value)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
- hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
- if (lsmid != 0 && lsmid != hp->lsmid->id)
+ lsm_for_each_hook(scall, getprocattr) {
+ if (lsmid != 0 && lsmid != scall->hl->lsmid->id)
continue;
- return hp->hook.getprocattr(p, name, value);
+ return scall->hl->hook.getprocattr(p, name, value);
}
return LSM_RET_DEFAULT(getprocattr);
}
@@ -4131,12 +4250,12 @@ int security_getprocattr(struct task_struct *p, int lsmid, const char *name,
*/
int security_setprocattr(int lsmid, const char *name, void *value, size_t size)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
- hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
- if (lsmid != 0 && lsmid != hp->lsmid->id)
+ lsm_for_each_hook(scall, setprocattr) {
+ if (lsmid != 0 && lsmid != scall->hl->lsmid->id)
continue;
- return hp->hook.setprocattr(name, value, size);
+ return scall->hl->hook.setprocattr(name, value, size);
}
return LSM_RET_DEFAULT(setprocattr);
}
@@ -4674,6 +4793,20 @@ int security_socket_getpeersec_dgram(struct socket *sock,
EXPORT_SYMBOL(security_socket_getpeersec_dgram);
/**
+ * lsm_sock_alloc - allocate a composite sock blob
+ * @sock: the sock that needs a blob
+ * @gfp: allocation mode
+ *
+ * Allocate the sock blob for all the modules
+ *
+ * Returns 0, or -ENOMEM if memory can't be allocated.
+ */
+static int lsm_sock_alloc(struct sock *sock, gfp_t gfp)
+{
+ return lsm_blob_alloc(&sock->sk_security, blob_sizes.lbs_sock, gfp);
+}
+
+/**
* security_sk_alloc() - Allocate and initialize a sock's LSM blob
* @sk: sock
* @family: protocol family
@@ -4686,7 +4819,14 @@ EXPORT_SYMBOL(security_socket_getpeersec_dgram);
*/
int security_sk_alloc(struct sock *sk, int family, gfp_t priority)
{
- return call_int_hook(sk_alloc_security, sk, family, priority);
+ int rc = lsm_sock_alloc(sk, priority);
+
+ if (unlikely(rc))
+ return rc;
+ rc = call_int_hook(sk_alloc_security, sk, family, priority);
+ if (unlikely(rc))
+ security_sk_free(sk);
+ return rc;
}
/**
@@ -4698,6 +4838,8 @@ int security_sk_alloc(struct sock *sk, int family, gfp_t priority)
void security_sk_free(struct sock *sk)
{
call_void_hook(sk_free_security, sk);
+ kfree(sk->sk_security);
+ sk->sk_security = NULL;
}
/**
@@ -4845,7 +4987,18 @@ EXPORT_SYMBOL(security_secmark_refcount_dec);
*/
int security_tun_dev_alloc_security(void **security)
{
- return call_int_hook(tun_dev_alloc_security, security);
+ int rc;
+
+ rc = lsm_blob_alloc(security, blob_sizes.lbs_tun_dev, GFP_KERNEL);
+ if (rc)
+ return rc;
+
+ rc = call_int_hook(tun_dev_alloc_security, *security);
+ if (rc) {
+ kfree(*security);
+ *security = NULL;
+ }
+ return rc;
}
EXPORT_SYMBOL(security_tun_dev_alloc_security);
@@ -4857,7 +5010,7 @@ EXPORT_SYMBOL(security_tun_dev_alloc_security);
*/
void security_tun_dev_free_security(void *security)
{
- call_void_hook(tun_dev_free_security, security);
+ kfree(security);
}
EXPORT_SYMBOL(security_tun_dev_free_security);
@@ -5053,7 +5206,18 @@ EXPORT_SYMBOL(security_ib_endport_manage_subnet);
*/
int security_ib_alloc_security(void **sec)
{
- return call_int_hook(ib_alloc_security, sec);
+ int rc;
+
+ rc = lsm_blob_alloc(sec, blob_sizes.lbs_ib, GFP_KERNEL);
+ if (rc)
+ return rc;
+
+ rc = call_int_hook(ib_alloc_security, *sec);
+ if (rc) {
+ kfree(*sec);
+ *sec = NULL;
+ }
+ return rc;
}
EXPORT_SYMBOL(security_ib_alloc_security);
@@ -5065,7 +5229,7 @@ EXPORT_SYMBOL(security_ib_alloc_security);
*/
void security_ib_free_security(void *sec)
{
- call_void_hook(ib_free_security, sec);
+ kfree(sec);
}
EXPORT_SYMBOL(security_ib_free_security);
#endif /* CONFIG_SECURITY_INFINIBAND */
@@ -5223,7 +5387,7 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x,
struct xfrm_policy *xp,
const struct flowi_common *flic)
{
- struct security_hook_list *hp;
+ struct lsm_static_call *scall;
int rc = LSM_RET_DEFAULT(xfrm_state_pol_flow_match);
/*
@@ -5235,9 +5399,8 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x,
* For speed optimization, we explicitly break the loop rather than
* using the macro
*/
- hlist_for_each_entry(hp, &security_hook_heads.xfrm_state_pol_flow_match,
- list) {
- rc = hp->hook.xfrm_state_pol_flow_match(x, xp, flic);
+ lsm_for_each_hook(scall, xfrm_state_pol_flow_match) {
+ rc = scall->hl->hook.xfrm_state_pol_flow_match(x, xp, flic);
break;
}
return rc;
@@ -5282,7 +5445,14 @@ EXPORT_SYMBOL(security_skb_classify_flow);
int security_key_alloc(struct key *key, const struct cred *cred,
unsigned long flags)
{
- return call_int_hook(key_alloc, key, cred, flags);
+ int rc = lsm_key_alloc(key);
+
+ if (unlikely(rc))
+ return rc;
+ rc = call_int_hook(key_alloc, key, cred, flags);
+ if (unlikely(rc))
+ security_key_free(key);
+ return rc;
}
/**
@@ -5293,7 +5463,8 @@ int security_key_alloc(struct key *key, const struct cred *cred,
*/
void security_key_free(struct key *key)
{
- call_void_hook(key_free, key);
+ kfree(key->security);
+ key->security = NULL;
}
/**
@@ -5596,6 +5767,85 @@ int security_locked_down(enum lockdown_reason what)
}
EXPORT_SYMBOL(security_locked_down);
+/**
+ * security_bdev_alloc() - Allocate a block device LSM blob
+ * @bdev: block device
+ *
+ * Allocate and attach a security structure to @bdev->bd_security. The
+ * security field is initialized to NULL when the bdev structure is
+ * allocated.
+ *
+ * Return: Return 0 if operation was successful.
+ */
+int security_bdev_alloc(struct block_device *bdev)
+{
+ int rc = 0;
+
+ rc = lsm_bdev_alloc(bdev);
+ if (unlikely(rc))
+ return rc;
+
+ rc = call_int_hook(bdev_alloc_security, bdev);
+ if (unlikely(rc))
+ security_bdev_free(bdev);
+
+ return rc;
+}
+EXPORT_SYMBOL(security_bdev_alloc);
+
+/**
+ * security_bdev_free() - Free a block device's LSM blob
+ * @bdev: block device
+ *
+ * Deallocate the bdev security structure and set @bdev->bd_security to NULL.
+ */
+void security_bdev_free(struct block_device *bdev)
+{
+ if (!bdev->bd_security)
+ return;
+
+ call_void_hook(bdev_free_security, bdev);
+
+ kfree(bdev->bd_security);
+ bdev->bd_security = NULL;
+}
+EXPORT_SYMBOL(security_bdev_free);
+
+/**
+ * security_bdev_setintegrity() - Set the device's integrity data
+ * @bdev: block device
+ * @type: type of integrity, e.g. hash digest, signature, etc
+ * @value: the integrity value
+ * @size: size of the integrity value
+ *
+ * Register a verified integrity measurement of a bdev with LSMs.
+ * LSMs should free the previously saved data if @value is NULL.
+ * Please note that the new hook should be invoked every time the security
+ * information is updated to keep these data current. For example, in dm-verity,
+ * if the mapping table is reloaded and configured to use a different dm-verity
+ * target with a new roothash and signing information, the previously stored
+ * data in the LSM blob will become obsolete. It is crucial to re-invoke the
+ * hook to refresh these data and ensure they are up to date. This necessity
+ * arises from the design of device-mapper, where a device-mapper device is
+ * first created, and then targets are subsequently loaded into it. These
+ * targets can be modified multiple times during the device's lifetime.
+ * Therefore, while the LSM blob is allocated during the creation of the block
+ * device, its actual contents are not initialized at this stage and can change
+ * substantially over time. This includes alterations from data that the LSMs
+ * 'trusts' to those they do not, making it essential to handle these changes
+ * correctly. Failure to address this dynamic aspect could potentially allow
+ * for bypassing LSM checks.
+ *
+ * Return: Returns 0 on success, negative values on failure.
+ */
+int security_bdev_setintegrity(struct block_device *bdev,
+ enum lsm_integrity_type type, const void *value,
+ size_t size)
+{
+ return call_int_hook(bdev_setintegrity, bdev, type, value, size);
+}
+EXPORT_SYMBOL(security_bdev_setintegrity);
+
#ifdef CONFIG_PERF_EVENTS
/**
* security_perf_event_open() - Check if a perf event open is allowed
@@ -5621,7 +5871,19 @@ int security_perf_event_open(struct perf_event_attr *attr, int type)
*/
int security_perf_event_alloc(struct perf_event *event)
{
- return call_int_hook(perf_event_alloc, event);
+ int rc;
+
+ rc = lsm_blob_alloc(&event->security, blob_sizes.lbs_perf_event,
+ GFP_KERNEL);
+ if (rc)
+ return rc;
+
+ rc = call_int_hook(perf_event_alloc, event);
+ if (rc) {
+ kfree(event->security);
+ event->security = NULL;
+ }
+ return rc;
}
/**
@@ -5632,7 +5894,8 @@ int security_perf_event_alloc(struct perf_event *event)
*/
void security_perf_event_free(struct perf_event *event)
{
- call_void_hook(perf_event_free, event);
+ kfree(event->security);
+ event->security = NULL;
}
/**
@@ -5703,3 +5966,13 @@ int security_uring_cmd(struct io_uring_cmd *ioucmd)
return call_int_hook(uring_cmd, ioucmd);
}
#endif /* CONFIG_IO_URING */
+
+/**
+ * security_initramfs_populated() - Notify LSMs that initramfs has been loaded
+ *
+ * Tells the LSMs the initramfs has been unpacked into the rootfs.
+ */
+void security_initramfs_populated(void)
+{
+ call_void_hook(initramfs_populated);
+}