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authorDavid Howells <dhowells@redhat.com>2008-11-14 10:39:28 +1100
committerJames Morris <jmorris@namei.org>2008-11-14 10:39:28 +1100
commit3a3b7ce9336952ea7b9564d976d068a238976c9d (patch)
tree3f0a3be33022492161f534636a20a4b1059f8236 /security/security.c
parent1bfdc75ae077d60a01572a7781ec6264d55ab1b9 (diff)
downloadlinux-2.6.34-ux500-3a3b7ce9336952ea7b9564d976d068a238976c9d.tar.gz
CRED: Allow kernel services to override LSM settings for task actions
Allow kernel services to override LSM settings appropriate to the actions performed by a task by duplicating a set of credentials, modifying it and then using task_struct::cred to point to it when performing operations on behalf of a task. This is used, for example, by CacheFiles which has to transparently access the cache on behalf of a process that thinks it is doing, say, NFS accesses with a potentially inappropriate (with respect to accessing the cache) set of credentials. This patch provides two LSM hooks for modifying a task security record: (*) security_kernel_act_as() which allows modification of the security datum with which a task acts on other objects (most notably files). (*) security_kernel_create_files_as() which allows modification of the security datum that is used to initialise the security data on a file that a task creates. The patch also provides four new credentials handling functions, which wrap the LSM functions: (1) prepare_kernel_cred() Prepare a set of credentials for a kernel service to use, based either on a daemon's credentials or on init_cred. All the keyrings are cleared. (2) set_security_override() Set the LSM security ID in a set of credentials to a specific security context, assuming permission from the LSM policy. (3) set_security_override_from_ctx() As (2), but takes the security context as a string. (4) set_create_files_as() Set the file creation LSM security ID in a set of credentials to be the same as that on a particular inode. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [Smack changes] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/security.c')
-rw-r--r--security/security.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/security/security.c b/security/security.c
index dc5babb2d6d..038ef04b2c7 100644
--- a/security/security.c
+++ b/security/security.c
@@ -616,6 +616,16 @@ void security_commit_creds(struct cred *new, const struct cred *old)
return security_ops->cred_commit(new, old);
}
+int security_kernel_act_as(struct cred *new, u32 secid)
+{
+ return security_ops->kernel_act_as(new, secid);
+}
+
+int security_kernel_create_files_as(struct cred *new, struct inode *inode)
+{
+ return security_ops->kernel_create_files_as(new, inode);
+}
+
int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags)
{
return security_ops->task_setuid(id0, id1, id2, flags);