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lua-lsm: add inode_setattr attributes #22

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100 changes: 98 additions & 2 deletions security/lua/lsm_defs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
#include <linux/security.h>
#include <linux/xattr.h>
#include <linux/cred.h>
#include <linux/mnt_idmapping.h>
#include <linux/prctl.h>
#include <linux/syscalls.h> /* for __MAP */
#include <linux/timekeeping.h> /* for ktime_get */
Expand Down Expand Up @@ -1020,16 +1021,111 @@ LUA_LSM_INT_DEFINE2(inode_permission, struct inode *, inode, int, mask)
lua_pushinteger(L, (lua_Integer)mask);
}

static void iattr_set_time(lua_State *L, const char *name,
const struct timespec64 *ts)
{
lua_createtable(L, 0, 2);
lua_pushinteger(L, ts->tv_sec);
lua_setfield(L, -2, "sec");
lua_pushinteger(L, ts->tv_nsec);
lua_setfield(L, -2, "nsec");
lua_setfield(L, -2, name);
}

static void iattr_set_integer(lua_State *L, const char *name, long long value)
{
lua_pushinteger(L, value);
lua_setfield(L, -2, name);
}

static void iattr_set_flags(lua_State *L, unsigned int mask)
{
static const struct cflag_opt fields[] = {
{ "atime_set", ATTR_ATIME_SET },
{ "mtime_set", ATTR_MTIME_SET },
{ "ctime_set", ATTR_CTIME_SET },
{ "times_set", ATTR_TIMES_SET },
{ "touch", ATTR_TOUCH },
{ "force", ATTR_FORCE },
{ "kill_suid", ATTR_KILL_SUID },
{ "kill_sgid", ATTR_KILL_SGID },
{ "kill_priv", ATTR_KILL_PRIV },
{ "from_file", ATTR_FILE },
{ "from_open", ATTR_OPEN },
{ "delegated", ATTR_DELEG },
{ NULL, 0 }
};
int i;

for (i = 0; fields[i].name; i++) {
if (mask & fields[i].flag) {
lua_pushboolean(L, 1);
lua_setfield(L, -2, fields[i].name);
}
}
}

static void iattr_set_ids(lua_State *L, struct mnt_idmap *idmap,
const struct inode *inode, const struct iattr *attr)
{
unsigned int ia_valid = attr->ia_valid;
kuid_t uid;
kgid_t gid;

if (ia_valid & ATTR_UID) {
uid = from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid);
if (uid_valid(uid)) {
lua_pushinteger(L, uid.val);
lua_setfield(L, -2, "uid");
}
}
if (ia_valid & ATTR_GID) {
gid = from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid);
if (gid_valid(gid)) {
lua_pushinteger(L, gid.val);
lua_setfield(L, -2, "gid");
}
}
}

static void newiattr(lua_State *L, struct mnt_idmap *idmap,
struct dentry *dentry, const struct iattr *attr)
{
struct inode *inode = d_backing_inode(dentry);
unsigned int ia_valid = attr->ia_valid;

luaL_checkstack(L, 32, "iattr");
lua_createtable(L, 0, 20);

iattr_set_integer(L, "valid", ia_valid);

if (ia_valid & ATTR_MODE)
iattr_set_integer(L, "mode", attr->ia_mode);
if (inode)
iattr_set_ids(L, idmap, inode, attr);
if (ia_valid & ATTR_SIZE)
iattr_set_integer(L, "size", attr->ia_size);

if (ia_valid & ATTR_ATIME)
iattr_set_time(L, "atime", &attr->ia_atime);
if (ia_valid & ATTR_MTIME)
iattr_set_time(L, "mtime", &attr->ia_mtime);
if (ia_valid & ATTR_CTIME)
iattr_set_time(L, "ctime", &attr->ia_ctime);

iattr_set_flags(L, ia_valid);
}

/**
* TODO: inode_setattr
* inode_setattr
* Default: 0
*/
LUA_LSM_INT_DEFINE3(inode_setattr, struct mnt_idmap *, idmap,
struct dentry *, dentry, struct iattr *, attr)
{
*newmntidmap(L) = idmap;
*newdentry(L) = dentry;
lua_pushnil(L); /* TODO: attr */
newiattr(L, idmap, dentry, attr);
}

/**
Expand Down