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/**
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 * @file
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 * @brief
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 *
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 * @author  Anton Kozlov
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 * @date    14.02.2013
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 */
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#include <errno.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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#include <fs/vfs.h>
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#include <fs/inode.h>
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#include <fs/inode_operation.h>
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#include <fs/hlpr_path.h>
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#include <security/security.h>
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int fs_perm_mask(struct inode *node) {
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	int perm = node->i_mode & S_IRWXA;
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	uid_t uid = getuid();
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	if (uid == 0) {
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		/* super user */
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		return S_IRWXO;
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	}
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	if (node->i_owner_id == uid) {
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		perm >>= 6;
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	} else if (node->i_group_id == getgid()) {
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		perm >>= 3;
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	}
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	perm &= S_IRWXO;
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	return perm;
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}
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int fs_perm_check(struct inode *node, int fd_flags) {
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	/* Here, we rely on the fact that fd_flags correspond to OTH perm bits. */
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	return (fd_flags & ~fs_perm_mask(node)) ? -EACCES :
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		security_node_permissions(node, fd_flags);
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}
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int fs_perm_lookup(const char *path, const char **pathlast,
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		struct path *nodelast) {
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	struct path node_path;
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	struct path dir_path;
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	size_t len = 0;
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	int ret;
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	if (!path) {
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		return -EINVAL;
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	}
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	if (path[0] == '/') {
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		vfs_get_root_path(&node_path);
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	} else {
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		vfs_get_leaf_path(&node_path);
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	}
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	do {
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		struct inode *dnode;
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		path = path_next(path + len, &len);
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		*nodelast = node_path;
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		if (pathlast != NULL) {
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			*pathlast = path;
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		}
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		if (!path) {
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			return 0;
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		}
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		if (0 != (ret = fs_perm_check(node_path.node, S_IXOTH))) {
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			return ret;
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		}
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		dir_path = node_path;
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		if_mounted_follow_down(&node_path);
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		dnode = node_path.node;
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		vfs_lookup_childn(&node_path, path, len, &node_path);
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		if (NULL != node_path.node) {
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			if (dnode && dnode->i_ops && dnode->i_ops->ino_lookup) {
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				if (dnode->i_ops == dir_path.node->i_ops) {
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					dnode->i_ops->ino_lookup(node_path.node, path, dir_path.node);
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				} else {
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					/* find mount inode */
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					dnode->i_ops->ino_lookup(node_path.node, path, NULL);
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				}
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			}
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		}
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	} while (node_path.node);
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	return -ENOENT;
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}
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int fs_perm_lookup_relative(const char *path, const char **pathlast,
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		struct path *nodelast) {
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	int ret = 0;
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	if (0 != (ret = fs_perm_lookup(path, pathlast, nodelast))) {
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		return ret;
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	}
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	if (!S_ISDIR(nodelast->node->i_mode)) {
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		return 0;
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	}
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	return 0;
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}
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