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Subject[PATCH 01/10] keys: sparse: Fix key_fs[ug]id_changed() [ver #3]
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Date
Sparse warnings are incurred by key_fs[ug]id_changed() due to unprotected
accesses of tsk->cred, which is marked __rcu.

Fix this by passing the new cred struct to these functions from
commit_creds() rather than the task pointer.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
---

include/linux/key.h | 8 ++++----
kernel/cred.c | 4 ++--
security/keys/process_keys.c | 22 ++++++++++------------
3 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/include/linux/key.h b/include/linux/key.h
index 7099985e35a9..1f09aad1c98c 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -402,8 +402,8 @@ extern struct ctl_table key_sysctls[];
* the userspace interface
*/
extern int install_thread_keyring_to_cred(struct cred *cred);
-extern void key_fsuid_changed(struct task_struct *tsk);
-extern void key_fsgid_changed(struct task_struct *tsk);
+extern void key_fsuid_changed(struct cred *new_cred);
+extern void key_fsgid_changed(struct cred *new_cred);
extern void key_init(void);

#else /* CONFIG_KEYS */
@@ -418,8 +418,8 @@ extern void key_init(void);
#define make_key_ref(k, p) NULL
#define key_ref_to_ptr(k) NULL
#define is_key_possessed(k) 0
-#define key_fsuid_changed(t) do { } while(0)
-#define key_fsgid_changed(t) do { } while(0)
+#define key_fsuid_changed(c) do { } while(0)
+#define key_fsgid_changed(c) do { } while(0)
#define key_init() do { } while(0)

#endif /* CONFIG_KEYS */
diff --git a/kernel/cred.c b/kernel/cred.c
index 45d77284aed0..3bd40de9e192 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -455,9 +455,9 @@ int commit_creds(struct cred *new)

/* alter the thread keyring */
if (!uid_eq(new->fsuid, old->fsuid))
- key_fsuid_changed(task);
+ key_fsuid_changed(new);
if (!gid_eq(new->fsgid, old->fsgid))
- key_fsgid_changed(task);
+ key_fsgid_changed(new);

/* do it
* RLIMIT_NPROC limits on user->processes have already been checked
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index f05f7125a7d5..ba5d3172cafe 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -293,28 +293,26 @@ static int install_session_keyring(struct key *keyring)
/*
* Handle the fsuid changing.
*/
-void key_fsuid_changed(struct task_struct *tsk)
+void key_fsuid_changed(struct cred *new_cred)
{
/* update the ownership of the thread keyring */
- BUG_ON(!tsk->cred);
- if (tsk->cred->thread_keyring) {
- down_write(&tsk->cred->thread_keyring->sem);
- tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
- up_write(&tsk->cred->thread_keyring->sem);
+ if (new_cred->thread_keyring) {
+ down_write(&new_cred->thread_keyring->sem);
+ new_cred->thread_keyring->uid = new_cred->fsuid;
+ up_write(&new_cred->thread_keyring->sem);
}
}

/*
* Handle the fsgid changing.
*/
-void key_fsgid_changed(struct task_struct *tsk)
+void key_fsgid_changed(struct cred *new_cred)
{
/* update the ownership of the thread keyring */
- BUG_ON(!tsk->cred);
- if (tsk->cred->thread_keyring) {
- down_write(&tsk->cred->thread_keyring->sem);
- tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
- up_write(&tsk->cred->thread_keyring->sem);
+ if (new_cred->thread_keyring) {
+ down_write(&new_cred->thread_keyring->sem);
+ new_cred->thread_keyring->gid = new_cred->fsgid;
+ up_write(&new_cred->thread_keyring->sem);
}
}

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