diff options
Diffstat (limited to 'security')
| -rw-r--r-- | security/Kconfig.hardening | 76 | ||||
| -rw-r--r-- | security/ipe/audit.c | 19 | ||||
| -rw-r--r-- | security/ipe/fs.c | 25 | ||||
| -rw-r--r-- | security/ipe/policy.c | 17 | ||||
| -rw-r--r-- | security/ipe/policy_fs.c | 28 | ||||
| -rw-r--r-- | security/keys/gc.c | 4 | ||||
| -rw-r--r-- | security/keys/key.c | 5 | ||||
| -rw-r--r-- | security/selinux/ss/services.c | 16 | ||||
| -rw-r--r-- | security/selinux/xfrm.c | 2 |
9 files changed, 80 insertions, 112 deletions
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index c17366ce8224..fd1238753cad 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -1,22 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only menu "Kernel hardening options" -config GCC_PLUGIN_STRUCTLEAK - bool - help - While the kernel is built with warnings enabled for any missed - stack variable initializations, this warning is silenced for - anything passed by reference to another function, under the - occasionally misguided assumption that the function will do - the initialization. As this regularly leads to exploitable - flaws, this plugin is available to identify and zero-initialize - such variables, depending on the chosen level of coverage. - - This plugin was originally ported from grsecurity/PaX. More - information at: - * https://grsecurity.net/ - * https://pax.grsecurity.net/ - menu "Memory initialization" config CC_HAS_AUTO_VAR_INIT_PATTERN @@ -36,7 +20,6 @@ config CC_HAS_AUTO_VAR_INIT_ZERO choice prompt "Initialize kernel stack variables at function entry" - default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL if COMPILE_TEST && GCC_PLUGINS default INIT_STACK_ALL_PATTERN if COMPILE_TEST && CC_HAS_AUTO_VAR_INIT_PATTERN default INIT_STACK_ALL_ZERO if CC_HAS_AUTO_VAR_INIT_ZERO default INIT_STACK_NONE @@ -60,55 +43,6 @@ choice classes of uninitialized stack variable exploits and information exposures. - config GCC_PLUGIN_STRUCTLEAK_USER - bool "zero-init structs marked for userspace (weak)" - # Plugin can be removed once the kernel only supports GCC 12+ - depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO - select GCC_PLUGIN_STRUCTLEAK - help - Zero-initialize any structures on the stack containing - a __user attribute. This can prevent some classes of - uninitialized stack variable exploits and information - exposures, like CVE-2013-2141: - https://git.kernel.org/linus/b9e146d8eb3b9eca - - config GCC_PLUGIN_STRUCTLEAK_BYREF - bool "zero-init structs passed by reference (strong)" - # Plugin can be removed once the kernel only supports GCC 12+ - depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO - depends on !(KASAN && KASAN_STACK) - select GCC_PLUGIN_STRUCTLEAK - help - Zero-initialize any structures on the stack that may - be passed by reference and had not already been - explicitly initialized. This can prevent most classes - of uninitialized stack variable exploits and information - exposures, like CVE-2017-1000410: - https://git.kernel.org/linus/06e7e776ca4d3654 - - As a side-effect, this keeps a lot of variables on the - stack that can otherwise be optimized out, so combining - this with CONFIG_KASAN_STACK can lead to a stack overflow - and is disallowed. - - config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL - bool "zero-init everything passed by reference (very strong)" - # Plugin can be removed once the kernel only supports GCC 12+ - depends on GCC_PLUGINS && !CC_HAS_AUTO_VAR_INIT_ZERO - depends on !(KASAN && KASAN_STACK) - select GCC_PLUGIN_STRUCTLEAK - help - Zero-initialize any stack variables that may be passed - by reference and had not already been explicitly - initialized. This is intended to eliminate all classes - of uninitialized stack variable exploits and information - exposures. - - As a side-effect, this keeps a lot of variables on the - stack that can otherwise be optimized out, so combining - this with CONFIG_KASAN_STACK can lead to a stack overflow - and is disallowed. - config INIT_STACK_ALL_PATTERN bool "pattern-init everything (strongest)" depends on CC_HAS_AUTO_VAR_INIT_PATTERN @@ -148,16 +82,6 @@ choice endchoice -config GCC_PLUGIN_STRUCTLEAK_VERBOSE - bool "Report forcefully initialized variables" - depends on GCC_PLUGIN_STRUCTLEAK - depends on !COMPILE_TEST # too noisy - help - This option will cause a warning to be printed each time the - structleak plugin finds a variable it thinks needs to be - initialized. Since not all existing initializers are detected - by the plugin, this can produce false positive warnings. - config GCC_PLUGIN_STACKLEAK bool "Poison kernel stack before returning from syscalls" depends on GCC_PLUGINS diff --git a/security/ipe/audit.c b/security/ipe/audit.c index f05f0caa4850..9668ecc5acd5 100644 --- a/security/ipe/audit.c +++ b/security/ipe/audit.c @@ -21,6 +21,8 @@ #define AUDIT_POLICY_LOAD_FMT "policy_name=\"%s\" policy_version=%hu.%hu.%hu "\ "policy_digest=" IPE_AUDIT_HASH_ALG ":" +#define AUDIT_POLICY_LOAD_NULL_FMT "policy_name=? policy_version=? "\ + "policy_digest=?" #define AUDIT_OLD_ACTIVE_POLICY_FMT "old_active_pol_name=\"%s\" "\ "old_active_pol_version=%hu.%hu.%hu "\ "old_policy_digest=" IPE_AUDIT_HASH_ALG ":" @@ -248,22 +250,29 @@ void ipe_audit_policy_activation(const struct ipe_policy *const op, } /** - * ipe_audit_policy_load() - Audit a policy being loaded into the kernel. - * @p: Supplies a pointer to the policy to audit. + * ipe_audit_policy_load() - Audit a policy loading event. + * @p: Supplies a pointer to the policy to audit or an error pointer. */ void ipe_audit_policy_load(const struct ipe_policy *const p) { struct audit_buffer *ab; + int err = 0; ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_IPE_POLICY_LOAD); if (!ab) return; - audit_policy(ab, AUDIT_POLICY_LOAD_FMT, p); - audit_log_format(ab, " auid=%u ses=%u lsm=ipe res=1", + if (!IS_ERR(p)) { + audit_policy(ab, AUDIT_POLICY_LOAD_FMT, p); + } else { + audit_log_format(ab, AUDIT_POLICY_LOAD_NULL_FMT); + err = PTR_ERR(p); + } + + audit_log_format(ab, " auid=%u ses=%u lsm=ipe res=%d errno=%d", from_kuid(&init_user_ns, audit_get_loginuid(current)), - audit_get_sessionid(current)); + audit_get_sessionid(current), !err, err); audit_log_end(ab); } diff --git a/security/ipe/fs.c b/security/ipe/fs.c index 5b6d19fb844a..f40e50bfd2e7 100644 --- a/security/ipe/fs.c +++ b/security/ipe/fs.c @@ -133,6 +133,8 @@ static ssize_t getenforce(struct file *f, char __user *data, * * %-ERANGE - Policy version number overflow * * %-EINVAL - Policy version parsing error * * %-EEXIST - Same name policy already deployed + * * %-ENOKEY - Policy signing key not found + * * %-EKEYREJECTED - Policy signature verification failed */ static ssize_t new_policy(struct file *f, const char __user *data, size_t len, loff_t *offset) @@ -141,12 +143,17 @@ static ssize_t new_policy(struct file *f, const char __user *data, char *copy = NULL; int rc = 0; - if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) - return -EPERM; + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) { + rc = -EPERM; + goto out; + } copy = memdup_user_nul(data, len); - if (IS_ERR(copy)) - return PTR_ERR(copy); + if (IS_ERR(copy)) { + rc = PTR_ERR(copy); + copy = NULL; + goto out; + } p = ipe_new_policy(NULL, 0, copy, len); if (IS_ERR(p)) { @@ -158,12 +165,14 @@ static ssize_t new_policy(struct file *f, const char __user *data, if (rc) goto out; - ipe_audit_policy_load(p); - out: - if (rc < 0) - ipe_free_policy(p); kfree(copy); + if (rc < 0) { + ipe_free_policy(p); + ipe_audit_policy_load(ERR_PTR(rc)); + } else { + ipe_audit_policy_load(p); + } return (rc < 0) ? rc : len; } diff --git a/security/ipe/policy.c b/security/ipe/policy.c index b628f696e32b..1c58c29886e8 100644 --- a/security/ipe/policy.c +++ b/security/ipe/policy.c @@ -84,8 +84,11 @@ static int set_pkcs7_data(void *ctx, const void *data, size_t len, * ipe_new_policy. * * Context: Requires root->i_rwsem to be held. - * Return: %0 on success. If an error occurs, the function will return - * the -errno. + * Return: + * * %0 - Success + * * %-ENOENT - Policy was deleted while updating + * * %-EINVAL - Policy name mismatch + * * %-ESTALE - Policy version too old */ int ipe_update_policy(struct inode *root, const char *text, size_t textlen, const char *pkcs7, size_t pkcs7len) @@ -146,10 +149,12 @@ err: * * Return: * * a pointer to the ipe_policy structure - Success - * * %-EBADMSG - Policy is invalid - * * %-ENOMEM - Out of memory (OOM) - * * %-ERANGE - Policy version number overflow - * * %-EINVAL - Policy version parsing error + * * %-EBADMSG - Policy is invalid + * * %-ENOMEM - Out of memory (OOM) + * * %-ERANGE - Policy version number overflow + * * %-EINVAL - Policy version parsing error + * * %-ENOKEY - Policy signing key not found + * * %-EKEYREJECTED - Policy signature verification failed */ struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, const char *pkcs7, size_t pkcs7len) diff --git a/security/ipe/policy_fs.c b/security/ipe/policy_fs.c index 4cb4dd7f5236..db26032ccbe1 100644 --- a/security/ipe/policy_fs.c +++ b/security/ipe/policy_fs.c @@ -12,6 +12,7 @@ #include "policy.h" #include "eval.h" #include "fs.h" +#include "audit.h" #define MAX_VERSION_SIZE ARRAY_SIZE("65535.65535.65535") @@ -286,8 +287,13 @@ static ssize_t getactive(struct file *f, char __user *data, * On success this updates the policy represented by $name, * in-place. * - * Return: Length of buffer written on success. If an error occurs, - * the function will return the -errno. + * Return: + * * Length of buffer written - Success + * * %-EPERM - Insufficient permission + * * %-ENOMEM - Out of memory (OOM) + * * %-ENOENT - Policy was deleted while updating + * * %-EINVAL - Policy name mismatch + * * %-ESTALE - Policy version too old */ static ssize_t update_policy(struct file *f, const char __user *data, size_t len, loff_t *offset) @@ -296,21 +302,29 @@ static ssize_t update_policy(struct file *f, const char __user *data, char *copy = NULL; int rc = 0; - if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) - return -EPERM; + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) { + rc = -EPERM; + goto out; + } copy = memdup_user(data, len); - if (IS_ERR(copy)) - return PTR_ERR(copy); + if (IS_ERR(copy)) { + rc = PTR_ERR(copy); + copy = NULL; + goto out; + } root = d_inode(f->f_path.dentry->d_parent); inode_lock(root); rc = ipe_update_policy(root, NULL, 0, copy, len); inode_unlock(root); +out: kfree(copy); - if (rc) + if (rc) { + ipe_audit_policy_load(ERR_PTR(rc)); return rc; + } return len; } diff --git a/security/keys/gc.c b/security/keys/gc.c index f27223ea4578..748e83818a76 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -218,8 +218,8 @@ continue_scanning: key = rb_entry(cursor, struct key, serial_node); cursor = rb_next(cursor); - if (test_bit(KEY_FLAG_FINAL_PUT, &key->flags)) { - smp_mb(); /* Clobber key->user after FINAL_PUT seen. */ + if (!test_bit_acquire(KEY_FLAG_USER_ALIVE, &key->flags)) { + /* Clobber key->user after final put seen. */ goto found_unreferenced_key; } diff --git a/security/keys/key.c b/security/keys/key.c index 7198cd2ac3a3..3bbdde778631 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -298,6 +298,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, key->restrict_link = restrict_link; key->last_used_at = ktime_get_real_seconds(); + key->flags |= 1 << KEY_FLAG_USER_ALIVE; if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) key->flags |= 1 << KEY_FLAG_IN_QUOTA; if (flags & KEY_ALLOC_BUILT_IN) @@ -658,8 +659,8 @@ void key_put(struct key *key) key->user->qnbytes -= key->quotalen; spin_unlock_irqrestore(&key->user->lock, flags); } - smp_mb(); /* key->user before FINAL_PUT set. */ - set_bit(KEY_FLAG_FINAL_PUT, &key->flags); + /* Mark key as safe for GC after key->user done. */ + clear_bit_unlock(KEY_FLAG_USER_ALIVE, &key->flags); schedule_work(&key_gc_work); } } diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 7becf3808818..d185754c2786 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -1909,11 +1909,17 @@ retry: goto out_unlock; } /* Obtain the sid for the context. */ - rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid); - if (rc == -ESTALE) { - rcu_read_unlock(); - context_destroy(&newcontext); - goto retry; + if (context_equal(scontext, &newcontext)) + *out_sid = ssid; + else if (context_equal(tcontext, &newcontext)) + *out_sid = tsid; + else { + rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid); + if (rc == -ESTALE) { + rcu_read_unlock(); + context_destroy(&newcontext); + goto retry; + } } out_unlock: rcu_read_unlock(); diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c index 90ec4ef1b082..61d56b0c2be1 100644 --- a/security/selinux/xfrm.c +++ b/security/selinux/xfrm.c @@ -94,7 +94,7 @@ static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp, ctx->ctx_doi = XFRM_SC_DOI_LSM; ctx->ctx_alg = XFRM_SC_ALG_SELINUX; - ctx->ctx_len = str_len; + ctx->ctx_len = str_len + 1; memcpy(ctx->ctx_str, &uctx[1], str_len); ctx->ctx_str[str_len] = '\0'; rc = security_context_to_sid(ctx->ctx_str, str_len, |