summaryrefslogtreecommitdiffstats
path: root/Documentation/credentials.txt
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2010-05-20 08:55:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-20 08:55:50 -0700
commit96b5b7f4f2d59b37c1fc2fba1ae25999accd6dcd (patch)
treecda421c6cd7533940b35504660a05a366a3ece0c /Documentation/credentials.txt
parentf72caf7e496465182eeda842ac66a5e75404ddf1 (diff)
parent539c99fd7fc28f8db257c713c10fb4aceadf8887 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (61 commits) KEYS: Return more accurate error codes LSM: Add __init to fixup function. TOMOYO: Add pathname grouping support. ima: remove ACPI dependency TPM: ACPI/PNP dependency removal security/selinux/ss: Use kstrdup TOMOYO: Use stack memory for pending entry. Revert "ima: remove ACPI dependency" Revert "TPM: ACPI/PNP dependency removal" KEYS: Do preallocation for __key_link() TOMOYO: Use mutex_lock_interruptible. KEYS: Better handling of errors from construct_alloc_key() KEYS: keyring_serialise_link_sem is only needed for keyring->keyring links TOMOYO: Use GFP_NOFS rather than GFP_KERNEL. ima: remove ACPI dependency TPM: ACPI/PNP dependency removal selinux: generalize disabling of execmem for plt-in-heap archs LSM Audit: rename LSM_AUDIT_NO_AUDIT to LSM_AUDIT_DATA_NONE CRED: Holding a spinlock does not imply the holding of RCU read lock SMACK: Don't #include Ext2 headers ...
Diffstat (limited to 'Documentation/credentials.txt')
-rw-r--r--Documentation/credentials.txt14
1 files changed, 5 insertions, 9 deletions
diff --git a/Documentation/credentials.txt b/Documentation/credentials.txt
index df03169782e..a2db3528700 100644
--- a/Documentation/credentials.txt
+++ b/Documentation/credentials.txt
@@ -408,9 +408,6 @@ This should be used inside the RCU read lock, as in the following example:
...
}
-A function need not get RCU read lock to use __task_cred() if it is holding a
-spinlock at the time as this implicitly holds the RCU read lock.
-
Should it be necessary to hold another task's credentials for a long period of
time, and possibly to sleep whilst doing so, then the caller should get a
reference on them using:
@@ -426,17 +423,16 @@ credentials, hiding the RCU magic from the caller:
uid_t task_uid(task) Task's real UID
uid_t task_euid(task) Task's effective UID
-If the caller is holding a spinlock or the RCU read lock at the time anyway,
-then:
+If the caller is holding the RCU read lock at the time anyway, then:
__task_cred(task)->uid
__task_cred(task)->euid
should be used instead. Similarly, if multiple aspects of a task's credentials
-need to be accessed, RCU read lock or a spinlock should be used, __task_cred()
-called, the result stored in a temporary pointer and then the credential
-aspects called from that before dropping the lock. This prevents the
-potentially expensive RCU magic from being invoked multiple times.
+need to be accessed, RCU read lock should be used, __task_cred() called, the
+result stored in a temporary pointer and then the credential aspects called
+from that before dropping the lock. This prevents the potentially expensive
+RCU magic from being invoked multiple times.
Should some other single aspect of another task's credentials need to be
accessed, then this can be used: