From 78b7280cce23293f7570ad52c1ffe1485c6d9669 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 11 Mar 2011 17:57:23 +0000 Subject: KEYS: Improve /proc/keys Improve /proc/keys by: (1) Don't attempt to summarise the payload of a negated key. It won't have one. To this end, a helper function - key_is_instantiated() has been added that allows the caller to find out whether the key is positively instantiated (as opposed to being uninstantiated or negatively instantiated). (2) Do show keys that are negative, expired or revoked rather than hiding them. This requires an override flag (no_state_check) to be passed to search_my_process_keyrings() and keyring_search_aux() to suppress this check. Without this, keys that are possessed by the caller, but only grant permissions to the caller if possessed are skipped as the possession check fails. Keys that are visible due to user, group or other checks are visible with or without this patch. Signed-off-by: David Howells Signed-off-by: James Morris --- security/keys/internal.h | 4 +++- security/keys/keyring.c | 37 ++++++++++++++++++++++++------------- security/keys/proc.c | 2 +- security/keys/process_keys.c | 12 +++++++----- security/keys/request_key.c | 3 +-- security/keys/request_key_auth.c | 3 ++- security/keys/user_defined.c | 4 ++-- 7 files changed, 40 insertions(+), 25 deletions(-) (limited to 'security') diff --git a/security/keys/internal.h b/security/keys/internal.h index 07a025f..f375152 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -109,11 +109,13 @@ extern key_ref_t keyring_search_aux(key_ref_t keyring_ref, const struct cred *cred, struct key_type *type, const void *description, - key_match_func_t match); + key_match_func_t match, + bool no_state_check); extern key_ref_t search_my_process_keyrings(struct key_type *type, const void *description, key_match_func_t match, + bool no_state_check, const struct cred *cred); extern key_ref_t search_process_keyrings(struct key_type *type, const void *description, diff --git a/security/keys/keyring.c b/security/keys/keyring.c index cdd2f3f..a06ffab 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -176,13 +176,15 @@ static void keyring_describe(const struct key *keyring, struct seq_file *m) else seq_puts(m, "[anon]"); - rcu_read_lock(); - klist = rcu_dereference(keyring->payload.subscriptions); - if (klist) - seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys); - else - seq_puts(m, ": empty"); - rcu_read_unlock(); + if (key_is_instantiated(keyring)) { + rcu_read_lock(); + klist = rcu_dereference(keyring->payload.subscriptions); + if (klist) + seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys); + else + seq_puts(m, ": empty"); + rcu_read_unlock(); + } } /* @@ -271,6 +273,7 @@ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, * @type: The type of key to search for. * @description: Parameter for @match. * @match: Function to rule on whether or not a key is the one required. + * @no_state_check: Don't check if a matching key is bad * * Search the supplied keyring tree for a key that matches the criteria given. * The root keyring and any linked keyrings must grant Search permission to the @@ -303,7 +306,8 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, const struct cred *cred, struct key_type *type, const void *description, - key_match_func_t match) + key_match_func_t match, + bool no_state_check) { struct { struct keyring_list *keylist; @@ -345,6 +349,8 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, kflags = keyring->flags; if (keyring->type == type && match(keyring, description)) { key = keyring; + if (no_state_check) + goto found; /* check it isn't negative and hasn't expired or been * revoked */ @@ -384,11 +390,13 @@ descend: continue; /* skip revoked keys and expired keys */ - if (kflags & (1 << KEY_FLAG_REVOKED)) - continue; + if (!no_state_check) { + if (kflags & (1 << KEY_FLAG_REVOKED)) + continue; - if (key->expiry && now.tv_sec >= key->expiry) - continue; + if (key->expiry && now.tv_sec >= key->expiry) + continue; + } /* keys that don't match */ if (!match(key, description)) @@ -399,6 +407,9 @@ descend: cred, KEY_SEARCH) < 0) continue; + if (no_state_check) + goto found; + /* we set a different error code if we pass a negative key */ if (kflags & (1 << KEY_FLAG_NEGATIVE)) { err = key->type_data.reject_error; @@ -478,7 +489,7 @@ key_ref_t keyring_search(key_ref_t keyring, return ERR_PTR(-ENOKEY); return keyring_search_aux(keyring, current->cred, - type, description, type->match); + type, description, type->match, false); } EXPORT_SYMBOL(keyring_search); diff --git a/security/keys/proc.c b/security/keys/proc.c index 525cf8a..49bbc97 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -199,7 +199,7 @@ static int proc_keys_show(struct seq_file *m, void *v) if (key->perm & KEY_POS_VIEW) { skey_ref = search_my_process_keyrings(key->type, key, lookup_user_key_possessed, - cred); + true, cred); if (!IS_ERR(skey_ref)) { key_ref_put(skey_ref); key_ref = make_key_ref(key, 1); diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index 930634e..6c0480d 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -331,6 +331,7 @@ void key_fsgid_changed(struct task_struct *tsk) key_ref_t search_my_process_keyrings(struct key_type *type, const void *description, key_match_func_t match, + bool no_state_check, const struct cred *cred) { key_ref_t key_ref, ret, err; @@ -350,7 +351,7 @@ key_ref_t search_my_process_keyrings(struct key_type *type, if (cred->thread_keyring) { key_ref = keyring_search_aux( make_key_ref(cred->thread_keyring, 1), - cred, type, description, match); + cred, type, description, match, no_state_check); if (!IS_ERR(key_ref)) goto found; @@ -371,7 +372,7 @@ key_ref_t search_my_process_keyrings(struct key_type *type, if (cred->tgcred->process_keyring) { key_ref = keyring_search_aux( make_key_ref(cred->tgcred->process_keyring, 1), - cred, type, description, match); + cred, type, description, match, no_state_check); if (!IS_ERR(key_ref)) goto found; @@ -395,7 +396,7 @@ key_ref_t search_my_process_keyrings(struct key_type *type, make_key_ref(rcu_dereference( cred->tgcred->session_keyring), 1), - cred, type, description, match); + cred, type, description, match, no_state_check); rcu_read_unlock(); if (!IS_ERR(key_ref)) @@ -417,7 +418,7 @@ key_ref_t search_my_process_keyrings(struct key_type *type, else if (cred->user->session_keyring) { key_ref = keyring_search_aux( make_key_ref(cred->user->session_keyring, 1), - cred, type, description, match); + cred, type, description, match, no_state_check); if (!IS_ERR(key_ref)) goto found; @@ -459,7 +460,8 @@ key_ref_t search_process_keyrings(struct key_type *type, might_sleep(); - key_ref = search_my_process_keyrings(type, description, match, cred); + key_ref = search_my_process_keyrings(type, description, match, + false, cred); if (!IS_ERR(key_ref)) goto found; err = key_ref; diff --git a/security/keys/request_key.c b/security/keys/request_key.c index df3c041..b18a717 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -530,8 +530,7 @@ struct key *request_key_and_link(struct key_type *type, dest_keyring, flags); /* search all the process keyrings for a key */ - key_ref = search_process_keyrings(type, description, type->match, - cred); + key_ref = search_process_keyrings(type, description, type->match, cred); if (!IS_ERR(key_ref)) { key = key_ref_to_ptr(key_ref); diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c index 6816403..f6337c9 100644 --- a/security/keys/request_key_auth.c +++ b/security/keys/request_key_auth.c @@ -59,7 +59,8 @@ static void request_key_auth_describe(const struct key *key, seq_puts(m, "key:"); seq_puts(m, key->description); - seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); + if (key_is_instantiated(key)) + seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); } /* diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c index c6ca866..63bb1aa 100644 --- a/security/keys/user_defined.c +++ b/security/keys/user_defined.c @@ -169,8 +169,8 @@ EXPORT_SYMBOL_GPL(user_destroy); void user_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); - - seq_printf(m, ": %u", key->datalen); + if (key_is_instantiated(key)) + seq_printf(m, ": %u", key->datalen); } EXPORT_SYMBOL_GPL(user_describe); -- cgit v1.1 From 4aab1e896a0a9d57420ff2867caa5a369123d8cb Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 11 Mar 2011 17:57:33 +0000 Subject: KEYS: Make request_key() and co. return an error for a negative key Make request_key() and co. return an error for a negative or rejected key. If the key was simply negated, then return ENOKEY, otherwise return the error with which it was rejected. Without this patch, the following command returns a key number (with the latest keyutils): [root@andromeda ~]# keyctl request2 user debug:foo rejected @s 586569904 Trying to print the key merely gets you a permission denied error: [root@andromeda ~]# keyctl print 586569904 keyctl_read_alloc: Permission denied Doing another request_key() call does get you the error, as long as it hasn't expired yet: [root@andromeda ~]# keyctl request user debug:foo request_key: Key was rejected by service Signed-off-by: David Howells Signed-off-by: James Morris --- security/keys/keyctl.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'security') diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 427fddc..eca5191 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -206,8 +206,14 @@ SYSCALL_DEFINE4(request_key, const char __user *, _type, goto error5; } + /* wait for the key to finish being constructed */ + ret = wait_for_key_construction(key, 1); + if (ret < 0) + goto error6; + ret = key->serial; +error6: key_put(key); error5: key_type_put(ktype); -- cgit v1.1 From 5806896019ceaa0a1e808182afb4bba33c948ad6 Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Mon, 14 Mar 2011 19:32:21 -0400 Subject: security: select correct default LSM_MMAP_MIN_ADDR on ARM. The default for this is universally set to 64k, but the help says: For most ia64, ppc64 and x86 users with lots of address space a value of 65536 is reasonable and should cause no problems. On arm and other archs it should not be higher than 32768. The text is right, in that we are seeing selinux-enabled ARM targets that fail to launch /sbin/init because selinux blocks a memory map. So select the right value if we know we are building ARM. Signed-off-by: Paul Gortmaker Signed-off-by: James Morris --- security/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'security') diff --git a/security/Kconfig b/security/Kconfig index 95accd4..e0f08b5 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -167,6 +167,7 @@ config INTEL_TXT config LSM_MMAP_MIN_ADDR int "Low address space for LSM to protect from user allocation" depends on SECURITY && SECURITY_SELINUX + default 32768 if ARM default 65536 help This is the portion of low virtual memory which should be protected -- cgit v1.1