From ceb73c12047b8d543570b23353e7848eb7c540a1 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 25 Jan 2011 16:34:28 +0000 Subject: KEYS: Fix __key_link_end() quota fixup on error Fix __key_link_end()'s attempt to fix up the quota if an error occurs. There are two erroneous cases: Firstly, we always decrease the quota if the preallocated replacement keyring needs cleaning up, irrespective of whether or not we should (we may have replaced a pointer rather than adding another pointer). Secondly, we never clean up the quota if we added a pointer without the keyring storage being extended (we allocate multiple pointers at a time, even if we're not going to use them all immediately). We handle this by setting the bottom bit of the preallocation pointer in __key_link_begin() to indicate that the quota needs fixing up, which is then passed to __key_link() (which clears the whole thing) and __key_link_end(). Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- security/keys/internal.h | 6 +++--- security/keys/key.c | 8 ++++---- security/keys/keyring.c | 31 +++++++++++++++++++------------ security/keys/request_key.c | 2 +- 4 files changed, 27 insertions(+), 20 deletions(-) (limited to 'security') diff --git a/security/keys/internal.h b/security/keys/internal.h index edfa50dbd6f5..a52aa7c88b41 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -87,13 +87,13 @@ extern void key_type_put(struct key_type *ktype); extern int __key_link_begin(struct key *keyring, const struct key_type *type, const char *description, - struct keyring_list **_prealloc); + unsigned long *_prealloc); extern int __key_link_check_live_key(struct key *keyring, struct key *key); extern void __key_link(struct key *keyring, struct key *key, - struct keyring_list **_prealloc); + unsigned long *_prealloc); extern void __key_link_end(struct key *keyring, struct key_type *type, - struct keyring_list *prealloc); + unsigned long prealloc); extern key_ref_t __keyring_search_one(key_ref_t keyring_ref, const struct key_type *type, diff --git a/security/keys/key.c b/security/keys/key.c index 84d4eb568b08..1c2d43dc5107 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -415,7 +415,7 @@ static int __key_instantiate_and_link(struct key *key, size_t datalen, struct key *keyring, struct key *authkey, - struct keyring_list **_prealloc) + unsigned long *_prealloc) { int ret, awaken; @@ -481,7 +481,7 @@ int key_instantiate_and_link(struct key *key, struct key *keyring, struct key *authkey) { - struct keyring_list *prealloc; + unsigned long prealloc; int ret; if (keyring) { @@ -526,7 +526,7 @@ int key_negate_and_link(struct key *key, struct key *keyring, struct key *authkey) { - struct keyring_list *prealloc; + unsigned long prealloc; struct timespec now; int ret, awaken, link_ret = 0; @@ -814,7 +814,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, key_perm_t perm, unsigned long flags) { - struct keyring_list *prealloc; + unsigned long prealloc; const struct cred *cred = current_cred(); struct key_type *ktype; struct key *keyring, *key = NULL; diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 92024ed12e0a..5620f084dede 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -25,6 +25,8 @@ (keyring)->payload.subscriptions, \ rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem))) +#define KEY_LINK_FIXQUOTA 1UL + /* * When plumbing the depths of the key tree, this sets a hard limit * set on how deep we're willing to go. @@ -699,11 +701,11 @@ static void keyring_unlink_rcu_disposal(struct rcu_head *rcu) * Preallocate memory so that a key can be linked into to a keyring. */ int __key_link_begin(struct key *keyring, const struct key_type *type, - const char *description, - struct keyring_list **_prealloc) + const char *description, unsigned long *_prealloc) __acquires(&keyring->sem) { struct keyring_list *klist, *nklist; + unsigned long prealloc; unsigned max; size_t size; int loop, ret; @@ -746,6 +748,7 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, /* note replacement slot */ klist->delkey = nklist->delkey = loop; + prealloc = (unsigned long)nklist; goto done; } } @@ -760,6 +763,7 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, if (klist && klist->nkeys < klist->maxkeys) { /* there's sufficient slack space to append directly */ nklist = NULL; + prealloc = KEY_LINK_FIXQUOTA; } else { /* grow the key list */ max = 4; @@ -794,8 +798,9 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, nklist->keys[nklist->delkey] = NULL; } + prealloc = (unsigned long)nklist | KEY_LINK_FIXQUOTA; done: - *_prealloc = nklist; + *_prealloc = prealloc; kleave(" = 0"); return 0; @@ -836,12 +841,12 @@ int __key_link_check_live_key(struct key *keyring, struct key *key) * combination. */ void __key_link(struct key *keyring, struct key *key, - struct keyring_list **_prealloc) + unsigned long *_prealloc) { struct keyring_list *klist, *nklist; - nklist = *_prealloc; - *_prealloc = NULL; + nklist = (struct keyring_list *)(*_prealloc & ~KEY_LINK_FIXQUOTA); + *_prealloc = 0; kenter("%d,%d,%p", keyring->serial, key->serial, nklist); @@ -881,20 +886,22 @@ void __key_link(struct key *keyring, struct key *key, * Must be called with __key_link_begin() having being called. */ void __key_link_end(struct key *keyring, struct key_type *type, - struct keyring_list *prealloc) + unsigned long prealloc) __releases(&keyring->sem) { BUG_ON(type == NULL); BUG_ON(type->name == NULL); - kenter("%d,%s,%p", keyring->serial, type->name, prealloc); + kenter("%d,%s,%lx", keyring->serial, type->name, prealloc); if (type == &key_type_keyring) up_write(&keyring_serialise_link_sem); if (prealloc) { - kfree(prealloc); - key_payload_reserve(keyring, - keyring->datalen - KEYQUOTA_LINK_BYTES); + if (prealloc & KEY_LINK_FIXQUOTA) + key_payload_reserve(keyring, + keyring->datalen - + KEYQUOTA_LINK_BYTES); + kfree((struct keyring_list *)(prealloc & ~KEY_LINK_FIXQUOTA)); } up_write(&keyring->sem); } @@ -921,7 +928,7 @@ void __key_link_end(struct key *keyring, struct key_type *type, */ int key_link(struct key *keyring, struct key *key) { - struct keyring_list *prealloc; + unsigned long prealloc; int ret; key_check(keyring); diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 9a7fb3914b27..a3dc0d460def 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -352,8 +352,8 @@ static int construct_alloc_key(struct key_type *type, struct key_user *user, struct key **_key) { - struct keyring_list *prealloc; const struct cred *cred = current_cred(); + unsigned long prealloc; struct key *key; key_ref_t key_ref; int ret; -- cgit v1.3-14-g43fede From 2edeaa34a6e3f2c43b667f6c4f7b27944b811695 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Mon, 7 Feb 2011 13:36:10 +0000 Subject: CRED: Fix BUG() upon security_cred_alloc_blank() failure In cred_alloc_blank() since 2.6.32, abort_creds(new) is called with new->security == NULL and new->magic == 0 when security_cred_alloc_blank() returns an error. As a result, BUG() will be triggered if SELinux is enabled or CONFIG_DEBUG_CREDENTIALS=y. If CONFIG_DEBUG_CREDENTIALS=y, BUG() is called from __invalid_creds() because cred->magic == 0. Failing that, BUG() is called from selinux_cred_free() because selinux_cred_free() is not expecting cred->security == NULL. This does not affect smack_cred_free(), tomoyo_cred_free() or apparmor_cred_free(). Fix these bugs by (1) Set new->magic before calling security_cred_alloc_blank(). (2) Handle null cred->security in creds_are_invalid() and selinux_cred_free(). Signed-off-by: Tetsuo Handa Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- kernel/cred.c | 12 ++++++++---- security/selinux/hooks.c | 6 +++++- 2 files changed, 13 insertions(+), 5 deletions(-) (limited to 'security') diff --git a/kernel/cred.c b/kernel/cred.c index 6a1aa004e376..fcf104bb5aa9 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -252,13 +252,13 @@ struct cred *cred_alloc_blank(void) #endif atomic_set(&new->usage, 1); +#ifdef CONFIG_DEBUG_CREDENTIALS + new->magic = CRED_MAGIC; +#endif if (security_cred_alloc_blank(new, GFP_KERNEL) < 0) goto error; -#ifdef CONFIG_DEBUG_CREDENTIALS - new->magic = CRED_MAGIC; -#endif return new; error: @@ -748,7 +748,11 @@ bool creds_are_invalid(const struct cred *cred) if (cred->magic != CRED_MAGIC) return true; #ifdef CONFIG_SECURITY_SELINUX - if (selinux_is_enabled()) { + /* + * cred->security == NULL if security_cred_alloc_blank() or + * security_prepare_creds() returned an error. + */ + if (selinux_is_enabled() && cred->security) { if ((unsigned long) cred->security < PAGE_SIZE) return true; if ((*(u32 *)cred->security & 0xffffff00) == diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index e276eb468536..c8d699270687 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3198,7 +3198,11 @@ static void selinux_cred_free(struct cred *cred) { struct task_security_struct *tsec = cred->security; - BUG_ON((unsigned long) cred->security < PAGE_SIZE); + /* + * cred->security == NULL if security_cred_alloc_blank() or + * security_prepare_creds() returned an error. + */ + BUG_ON(cred->security && (unsigned long) cred->security < PAGE_SIZE); cred->security = (void *) 0x7UL; kfree(tsec); } -- cgit v1.3-14-g43fede From 6037b715d6fab139742c3df8851db4c823081561 Mon Sep 17 00:00:00 2001 From: Chris Wright Date: Wed, 9 Feb 2011 22:11:51 -0800 Subject: security: add cred argument to security_capable() Expand security_capable() to include cred, so that it can be usable in a wider range of call sites. Signed-off-by: Chris Wright Acked-by: Serge Hallyn Signed-off-by: James Morris --- include/linux/security.h | 6 +++--- kernel/capability.c | 2 +- security/security.c | 5 ++--- 3 files changed, 6 insertions(+), 7 deletions(-) (limited to 'security') diff --git a/include/linux/security.h b/include/linux/security.h index c642bb8b8f5a..b2b7f9749f5e 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1662,7 +1662,7 @@ int security_capset(struct cred *new, const struct cred *old, const kernel_cap_t *effective, const kernel_cap_t *inheritable, const kernel_cap_t *permitted); -int security_capable(int cap); +int security_capable(const struct cred *cred, int cap); int security_real_capable(struct task_struct *tsk, int cap); int security_real_capable_noaudit(struct task_struct *tsk, int cap); int security_sysctl(struct ctl_table *table, int op); @@ -1856,9 +1856,9 @@ static inline int security_capset(struct cred *new, return cap_capset(new, old, effective, inheritable, permitted); } -static inline int security_capable(int cap) +static inline int security_capable(const struct cred *cred, int cap) { - return cap_capable(current, current_cred(), cap, SECURITY_CAP_AUDIT); + return cap_capable(current, cred, cap, SECURITY_CAP_AUDIT); } static inline int security_real_capable(struct task_struct *tsk, int cap) diff --git a/kernel/capability.c b/kernel/capability.c index 2f05303715a5..9e9385f132c8 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -306,7 +306,7 @@ int capable(int cap) BUG(); } - if (security_capable(cap) == 0) { + if (security_capable(current_cred(), cap) == 0) { current->flags |= PF_SUPERPRIV; return 1; } diff --git a/security/security.c b/security/security.c index 739e40362f44..7b7308ace8c5 100644 --- a/security/security.c +++ b/security/security.c @@ -154,10 +154,9 @@ int security_capset(struct cred *new, const struct cred *old, effective, inheritable, permitted); } -int security_capable(int cap) +int security_capable(const struct cred *cred, int cap) { - return security_ops->capable(current, current_cred(), cap, - SECURITY_CAP_AUDIT); + return security_ops->capable(current, cred, cap, SECURITY_CAP_AUDIT); } int security_real_capable(struct task_struct *tsk, int cap) -- cgit v1.3-14-g43fede