Potentially dangerous key allowed for mass assignment Open
params.require(:user).permit(:role)
- Read upRead up
- Exclude checks
Mass assignment is a feature of Rails which allows an application to create a record from the values of a hash.
Example:
User.new(params[:user])
Unfortunately, if there is a user field called admin
which controls administrator access, now any user can make themselves an administrator.
attr_accessible
and attr_protected
can be used to limit mass assignment. However, Brakeman will warn unless attr_accessible
is used, or mass assignment is completely disabled.
There are two different mass assignment warnings which can arise. The first is when mass assignment actually occurs, such as the example above. This results in a warning like
Unprotected mass assignment near line 61: User.new(params[:user])
The other warning is raised whenever a model is found which does not use attr_accessible
. This produces generic warnings like
Mass assignment is not restricted using attr_accessible
with a list of affected models.
In Rails 3.1 and newer, mass assignment can easily be disabled:
config.active_record.whitelist_attributes = true
Unfortunately, it can also easily be bypassed:
User.new(params[:user], :without_protection => true)
Brakeman will warn on uses of without_protection
.
Favor modifier if
usage when having a single-line body. Another good alternative is the usage of control flow &&
/||
. Open
if @user.update(user_params)
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- Exclude checks
Checks for if and unless statements that would fit on one line
if written as a modifier if/unless. The maximum line length is
configured in the Metrics/LineLength
cop.
Example:
# bad
if condition
do_stuff(bar)
end
unless qux.empty?
Foo.do_something
end
# good
do_stuff(bar) if condition
Foo.do_something unless qux.empty?
Favor modifier if
usage when having a single-line body. Another good alternative is the usage of control flow &&
/||
. Open
if params[:search]
- Read upRead up
- Exclude checks
Checks for if and unless statements that would fit on one line
if written as a modifier if/unless. The maximum line length is
configured in the Metrics/LineLength
cop.
Example:
# bad
if condition
do_stuff(bar)
end
unless qux.empty?
Foo.do_something
end
# good
do_stuff(bar) if condition
Foo.do_something unless qux.empty?