X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fnamei.c;h=87f97ba90ad17d271baf15b2b2e65381a583c163;hb=471452104b8520337ae2fb48c4e61cd4896e025d;hp=fcfc5539252c2acec1bb80c71216e17baa86d8d5;hpb=a3c8b97396ef42edfb845788ba6f53b2a93ce980;p=safe%2Fjmp%2Flinux-2.6

diff --git a/fs/namei.c b/fs/namei.c
index fcfc553..87f97ba 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -169,19 +169,10 @@ void putname(const char *name)
 EXPORT_SYMBOL(putname);
 #endif
 
-
-/**
- * generic_permission  -  check for access rights on a Posix-like filesystem
- * @inode:	inode to check access rights for
- * @mask:	right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
- * @check_acl:	optional callback to check for Posix ACLs
- *
- * Used to check for read/write/execute permissions on a file.
- * We use "fsuid" for this, letting us set arbitrary permissions
- * for filesystem access without changing the "normal" uids which
- * are used for other things..
+/*
+ * This does basic POSIX ACL permission checking
  */
-int generic_permission(struct inode *inode, int mask,
+static int acl_permission_check(struct inode *inode, int mask,
 		int (*check_acl)(struct inode *inode, int mask))
 {
 	umode_t			mode = inode->i_mode;
@@ -193,9 +184,7 @@ int generic_permission(struct inode *inode, int mask,
 	else {
 		if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) {
 			int error = check_acl(inode, mask);
-			if (error == -EACCES)
-				goto check_capabilities;
-			else if (error != -EAGAIN)
+			if (error != -EAGAIN)
 				return error;
 		}
 
@@ -208,8 +197,32 @@ int generic_permission(struct inode *inode, int mask,
 	 */
 	if ((mask & ~mode) == 0)
 		return 0;
+	return -EACCES;
+}
+
+/**
+ * generic_permission  -  check for access rights on a Posix-like filesystem
+ * @inode:	inode to check access rights for
+ * @mask:	right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
+ * @check_acl:	optional callback to check for Posix ACLs
+ *
+ * Used to check for read/write/execute permissions on a file.
+ * We use "fsuid" for this, letting us set arbitrary permissions
+ * for filesystem access without changing the "normal" uids which
+ * are used for other things..
+ */
+int generic_permission(struct inode *inode, int mask,
+		int (*check_acl)(struct inode *inode, int mask))
+{
+	int ret;
+
+	/*
+	 * Do the basic POSIX ACL permission checks.
+	 */
+	ret = acl_permission_check(inode, mask, check_acl);
+	if (ret != -EACCES)
+		return ret;
 
- check_capabilities:
 	/*
 	 * Read/write DACs are always overridable.
 	 * Executable DACs are overridable if at least one exec bit is set.
@@ -262,7 +275,7 @@ int inode_permission(struct inode *inode, int mask)
 	if (inode->i_op->permission)
 		retval = inode->i_op->permission(inode, mask);
 	else
-		retval = generic_permission(inode, mask, NULL);
+		retval = generic_permission(inode, mask, inode->i_op->check_acl);
 
 	if (retval)
 		return retval;
@@ -432,29 +445,22 @@ static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name,
  */
 static int exec_permission_lite(struct inode *inode)
 {
-	umode_t	mode = inode->i_mode;
-
-	if (inode->i_op->permission)
-		return -EAGAIN;
-
-	if (current_fsuid() == inode->i_uid)
-		mode >>= 6;
-	else if (in_group_p(inode->i_gid))
-		mode >>= 3;
-
-	if (mode & MAY_EXEC)
-		goto ok;
+	int ret;
 
-	if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE))
-		goto ok;
-
-	if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE))
+	if (inode->i_op->permission) {
+		ret = inode->i_op->permission(inode, MAY_EXEC);
+		if (!ret)
+			goto ok;
+		return ret;
+	}
+	ret = acl_permission_check(inode, MAY_EXEC, inode->i_op->check_acl);
+	if (!ret)
 		goto ok;
 
-	if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH))
+	if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH))
 		goto ok;
 
-	return -EACCES;
+	return ret;
 ok:
 	return security_inode_permission(inode, MAY_EXEC);
 }
@@ -853,12 +859,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd)
 
 		nd->flags |= LOOKUP_CONTINUE;
 		err = exec_permission_lite(inode);
-		if (err == -EAGAIN)
-			err = inode_permission(nd->path.dentry->d_inode,
-					       MAY_EXEC);
-		if (!err)
-			err = ima_path_check(&nd->path, MAY_EXEC,
-				             IMA_COUNT_UPDATE);
  		if (err)
 			break;
 
@@ -1279,28 +1279,6 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 	return __lookup_hash(&this, base, NULL);
 }
 
-/**
- * lookup_one_noperm - bad hack for sysfs
- * @name:	pathname component to lookup
- * @base:	base directory to lookup from
- *
- * This is a variant of lookup_one_len that doesn't perform any permission
- * checks.   It's a horrible hack to work around the braindead sysfs
- * architecture and should not be used anywhere else.
- *
- * DON'T USE THIS FUNCTION EVER, thanks.
- */
-struct dentry *lookup_one_noperm(const char *name, struct dentry *base)
-{
-	int err;
-	struct qstr this;
-
-	err = __lookup_one_len(name, &this, base, strlen(name));
-	if (err)
-		return ERR_PTR(err);
-	return __lookup_hash(&this, base, NULL);
-}
-
 int user_path_at(int dfd, const char __user *name, unsigned flags,
 		 struct path *path)
 {
@@ -1678,6 +1656,15 @@ struct file *do_filp_open(int dfd, const char *pathname,
 	int will_write;
 	int flag = open_to_namei_flags(open_flag);
 
+	/*
+	 * O_SYNC is implemented as __O_SYNC|O_DSYNC.  As many places only
+	 * check for O_DSYNC if the need any syncing at all we enforce it's
+	 * always set instead of having to deal with possibly weird behaviour
+	 * for malicious applications setting only __O_SYNC.
+	 */
+	if (open_flag & __O_SYNC)
+		open_flag |= O_DSYNC;
+
 	if (!acc_mode)
 		acc_mode = MAY_OPEN | ACC_MODE(flag);