cifs: Support for an upcall to map SID to an uid and a gid

Commit Message

Shirish Pargaonkar Dec. 7, 2010, 5:11 p.m. UTC

None

Patch

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index a520091..d3ac6c8 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -23,6 +23,9 @@ 
 
 #include <linux/fs.h>
 #include <linux/slab.h>
+#include <linux/string.h>
+#include <keys/user-type.h>
+#include <linux/key-type.h>
 #include "cifspdu.h"
 #include "cifsglob.h"
 #include "cifsacl.h"
@@ -52,6 +55,102 @@  static const struct cifs_sid sid_authusers = {
 /* group users */
 static const struct cifs_sid sid_user = {1, 2 , {0, 0, 0, 0, 0, 5}, {} };
 
+static int
+cifs_acl_key_instantiate(struct key *key, const void *data, size_t datalen)
+{
+	char *payload;
+
+	payload = kmalloc(datalen, GFP_KERNEL);
+	if (!payload)
+		return -ENOMEM;
+
+	memcpy(payload, data, datalen);
+	key->payload.data = payload;
+	return 0;
+}
+
+static void
+cifs_acl_key_destroy(struct key *key)
+{
+	kfree(key->payload.data);
+}
+
+struct key_type cifs_acl_key_type = {
+	.name        = "cifs.cifs_acl",
+	.instantiate = cifs_acl_key_instantiate,
+	.destroy     = cifs_acl_key_destroy,
+	.describe    = user_describe,
+	.match       = user_match,
+};
+
+static void
+sid_to_str(struct cifs_sid *sidptr, char *sidstr)
+{
+	int i;
+	unsigned long saval;
+	char *strptr;
+
+	strptr = sidstr;
+
+	sprintf(strptr, "%s", "S");
+	strptr = sidstr + strlen(sidstr);
+
+	sprintf(strptr, "-%d", sidptr->revision);
+	strptr = sidstr + strlen(sidstr);
+
+	for (i = 0; i < 6; ++i) {
+		if (sidptr->authority[i]) {
+			sprintf(strptr, "-%d", sidptr->authority[i]);
+			strptr = sidstr + strlen(sidstr);
+		}
+	}
+
+	for (i = 0; i < sidptr->num_subauth; ++i) {
+		saval = le32_to_cpu(sidptr->sub_auth[i]);
+		sprintf(strptr, "-%ld", saval);
+		strptr = sidstr + strlen(sidstr);
+	}
+}
+
+static int
+sid_to_id(struct cifs_sid *psid, struct cifs_fattr *fattr, uint sidtype)
+{
+	int rc = 0;
+	char *sidstr, *strptr;
+	struct key *idkey;
+
+	sidstr = kzalloc(SIDLEN, GFP_KERNEL);
+	if (!sidstr)
+		return -ENOMEM;
+	strptr = sidstr;
+
+	if (sidtype == SIDOWNER)
+		sprintf(strptr, "%s", "os:");
+	else if (sidtype == SIDGROUP)
+		sprintf(strptr, "%s", "gs:");
+	else {
+		rc = -EINVAL;
+		goto idresolve_err;
+	}
+	strptr = sidstr + strlen(sidstr);
+
+	sid_to_str(psid, strptr);
+
+	idkey = request_key(&cifs_acl_key_type, sidstr, "");
+	if (IS_ERR(idkey))
+		cFYI(1, "%s: idkey error: %d\n", __func__, -ENOKEY);
+	else {
+		if (sidtype == SIDOWNER)
+			fattr->cf_uid = *(unsigned long *)idkey->payload.value;
+		else if (sidtype == SIDGROUP)
+			fattr->cf_gid = *(unsigned long *)idkey->payload.value;
+		key_put(idkey);
+	}
+
+idresolve_err:
+	kfree(sidstr);
+	return rc;
+}
 
 int match_sid(struct cifs_sid *ctsid)
 {
@@ -438,7 +537,6 @@  static int set_chmod_dacl(struct cifs_acl *pndacl, struct cifs_sid *pownersid,
 	return 0;
 }
 
-
 static int parse_sid(struct cifs_sid *psid, char *end_of_acl)
 {
 	/* BB need to add parm so we can store the SID BB */
@@ -476,7 +574,7 @@  static int parse_sid(struct cifs_sid *psid, char *end_of_acl)
 static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
 			  struct cifs_fattr *fattr)
 {
-	int rc;
+	int rc = 0;
 	struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
 	struct cifs_acl *dacl_ptr; /* no need for SACL ptr */
 	char *end_of_acl = ((char *)pntsd) + acl_len;
@@ -500,10 +598,16 @@  static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
 	rc = parse_sid(owner_sid_ptr, end_of_acl);
 	if (rc)
 		return rc;
+	rc = sid_to_id(owner_sid_ptr, fattr, SIDOWNER);
+	if (rc)
+		cFYI(1, "Can't resolve SID to an uid");
 
 	rc = parse_sid(group_sid_ptr, end_of_acl);
 	if (rc)
 		return rc;
+	rc = sid_to_id(group_sid_ptr, fattr, SIDGROUP);
+	if (rc)
+		cFYI(1, "Can't resolve SID to a gid");
 
 	if (dacloffset)
 		parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr,
@@ -511,14 +615,7 @@  static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
 	else
 		cFYI(1, "no ACL"); /* BB grant all or default perms? */
 
-/*	cifscred->uid = owner_sid_ptr->rid;
-	cifscred->gid = group_sid_ptr->rid;
-	memcpy((void *)(&(cifscred->osid)), (void *)owner_sid_ptr,
-			sizeof(struct cifs_sid));
-	memcpy((void *)(&(cifscred->gsid)), (void *)group_sid_ptr,
-			sizeof(struct cifs_sid)); */
-
-	return 0;
+	return rc;
 }
 
 
diff --git a/fs/cifs/cifsacl.h b/fs/cifs/cifsacl.h
index 6c8096c..74e69ca 100644
--- a/fs/cifs/cifsacl.h
+++ b/fs/cifs/cifsacl.h
@@ -39,6 +39,10 @@ 
 #define ACCESS_ALLOWED	0
 #define ACCESS_DENIED	1
 
+#define SIDOWNER 1
+#define SIDGROUP 2
+#define SIDLEN 150 /* S- 1 revision- 6 authorities- max 5 sub authorities */
+
 struct cifs_ntsd {
 	__le16 revision; /* revision level */
 	__le16 type;
@@ -76,6 +80,10 @@  struct cifs_wksid {
 
 #ifdef CONFIG_CIFS_EXPERIMENTAL
 
+#ifdef __KERNEL__
+extern struct key_type cifs_acl_key_type;
+#endif /* KERNEL */
+
 extern int match_sid(struct cifs_sid *);
 extern int compare_sids(const struct cifs_sid *, const struct cifs_sid *);
 
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 56a4b75..2753d54 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -46,6 +46,7 @@ 
 #include <linux/mm.h>
 #include <linux/key-type.h>
 #include "cifs_spnego.h"
+#include "cifsacl.h"
 #include "fscache.h"
 #define CIFS_MAGIC_NUMBER 0xFF534D42	/* the first four bytes of SMB PDUs */
 
@@ -973,11 +974,16 @@  init_cifs(void)
 	rc = register_key_type(&cifs_spnego_key_type);
 	if (rc)
 		goto out_unregister_filesystem;
+	rc = register_key_type(&cifs_acl_key_type);
+	if (rc)
+		goto out_unregister_keytype;
 #endif
 
 	return 0;
 
 #ifdef CONFIG_CIFS_UPCALL
+out_unregister_keytype:
+	unregister_key_type(&cifs_spnego_key_type);
 out_unregister_filesystem:
 	unregister_filesystem(&cifs_fs_type);
 #endif
@@ -1004,6 +1010,7 @@  exit_cifs(void)
 	cifs_dfs_release_automount_timer();
 #endif
 #ifdef CONFIG_CIFS_UPCALL
+	unregister_key_type(&cifs_acl_key_type);
 	unregister_key_type(&cifs_spnego_key_type);
 #endif
 	unregister_filesystem(&cifs_fs_type);