Do I need to know how to draw or paint to be a graphic designer?

I don't think you need to be able to draw to be a graphic designer.
It is a useful skill to have, but it is not something that you need to be able to do.
I believe graphic design is more about having good ideas and being able to execute them well.

I don't think "you have to" but I think it will be much better if you can.

I think its not that important ...
on my opinion I think a good taste on art in general is the key

Drawing, sketching or painting is a skill.
A skill can be acquired through continuous practice.
Nobody has been born with an instant skill to draw.
Aside from being creative, graphic designers too should have exceptional technical knowledge as the job would require the knowledge on how to use a lot of different instruments such as computers, cameras, and a lot of other gadgets.

I think it's better to know, because drawing gives you a good idea of proportions of anatomy, light and shading, and more important things that are very useful for graphic designers.

of course, you have to know how you drew by graphic program to be a graphic designer .

The simple answer is "no"...
you don't need to be a fine artist to be a graphic designer.
While it could help your career and your creative side, it is not necessary to be a sketch artist, painter or other type of artist in the traditional sense.
Graphic design is about taking elements such as type, photos, illustrations, and color and combining them to create effective messages.
In many cases, an artist will be hired to create a painting, illustration or drawing for a project that will then be handed off to a graphic designer to incorporate into the piece, whether it be an album cover, poster, business card, book cover or other graphic work.
In some cases, a graphic designer may also create his or her own illustrations, drawings and paintings, but it is not considered an essential part of a designer’s skill set.
It can be beneficial to a career or business if you do create your own artwork, as you could save money by completing more tasks yourself and any additional creative skills can improve your chances at landing certain design positions.
It is important to understand that you should have an understanding of the artwork that may be incorporated into your work, as well as the creativity to bring it together with other elements effectively.
Even if you are not creating the drawing or painting, you will want to understand the use of color, shapes, lines and the other elements of graphic design.

of course, you have to know how you drew by graphic program to be a graphic designer

To Draw, yes absolutely ..but by drawing i dont mean realistic human/animal/ or even landscape figures.....
you need to be able to convey your ideas through drawing and sketching otherwise you wont be able to widen your imagination & designs to paint, well i wouldnt say you have to, it's just a plus that helps you understand how colours go togther and the process of building up until you reach the final picture and coherence.....it's beneficial, but not crucial....But to draw, Yes!

Paint? No.
Draw.
Absolutely.
If you cannot express your ideas visually, you will be a miserable designer.
There is a misnomer that learning software will make you adequate.
Software is a tool, like a pencil.

no, to be a good graphic designer you must be as creative as possible, which does not really involve paper and pencil unless you need to plan out what you are going to do which should be pretty general not detailed.
but a decent hand in drawing can be very helpful for creating new ideas.
teaching yourself graphic design is doable but not impossible, but its best to go to school because your teachers and classmates can critique you and help you become a better artist.