make exec_permission(dir) really equivalent to inode_permission(dir, MAY_EXEC)

capability overrides apply only to the default case; if fs has ->permission()
that does _not_ call generic_permission(), we have no business doing them.
Moreover, if it has ->permission() that does call generic_permission(), we
have no need to recheck capabilities.

Besides, the capability overrides should apply only if we got EACCES from
acl_permission_check(); any other value (-EIO, etc.) should be returned
to caller, capabilities or not capabilities.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2011-06-19 01:50:08 -04:00
parent 43e15cdbef
commit 4cf27141cb

View file

@ -584,19 +584,19 @@ static inline int exec_permission(struct inode *inode, unsigned int flags)
if (inode->i_op->permission) {
ret = inode->i_op->permission(inode, MAY_EXEC, flags);
if (likely(!ret))
goto ok;
} else {
ret = acl_permission_check(inode, MAY_EXEC, flags,
inode->i_op->check_acl);
if (likely(!ret))
goto ok;
if (ret != -EACCES)
return ret;
if (ns_capable(ns, CAP_DAC_OVERRIDE) ||
ns_capable(ns, CAP_DAC_READ_SEARCH))
goto ok;
}
if (likely(!ret))
goto ok;
if (ret == -ECHILD)
return ret;
if (ns_capable(ns, CAP_DAC_OVERRIDE) ||
ns_capable(ns, CAP_DAC_READ_SEARCH))
goto ok;
return ret;
ok:
return security_inode_exec_permission(inode, flags);