OpenGL 4.1 not using entire vertex attributes at locations above 0 - c++

Question

I was drawing a 2D image on screen, and it was working successfully until I decided to add a color attribute. When I did this, I noticed the shader set the color of the entire image only to the first four components of my color buffer (which has 24 components).
Initialization:
//These are scaled before drawing
GLfloat vertex_buffer_data[] = {
0.0f, 0.0f, 1.0f,
1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 1.0f,
0.0f, 1.0f, 1.0f
};
glGenBuffers( 1, &m_2DVertexBuffer );
glBindBuffer( GL_ARRAY_BUFFER, m_2DVertexBuffer );
glBufferData( GL_ARRAY_BUFFER, sizeof( vertex_buffer_data ), vertex_buffer_data, GL_STATIC_DRAW );
//Simply test values to see which values the shader uses. Only uses the first 4.
GLfloat color_buffer_data[] = {
1.0f, 0.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 1.0f, 1.0f,
1.0f, 0.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f, 1.0f
};
glGenBuffers( 1, &m_2DColorBuffer );
glBindBuffer( GL_ARRAY_BUFFER, m_2DColorBuffer );
glBufferData( GL_ARRAY_BUFFER, sizeof( color_buffer_data ), color_buffer_data, GL_STATIC_DRAW );
Binding:
glEnableVertexAttribArray( 0 );
glEnableVertexAttribArray( 1 );
glBindBuffer( GL_ARRAY_BUFFER, m_2DVertexBuffer );
glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, 0, ( void * )0 );
glBindBuffer( GL_ARRAY_BUFFER, m_2DColorBuffer );
glVertexAttribPointer( 1, 4, GL_FLOAT, GL_FALSE, 0, ( void * )0 );
Drawing:
glDrawArrays( GL_TRIANGLE_STRIP, 0, 6 );
Vertex Shader:
#version 410
layout( location = 0 ) in vec3 position;
layout( location = 1 ) in vec4 color;
out vec2 textureCoord;
out vec4 textureColor;
uniform mat4 ProjView;
uniform mat4 ModelMat;
uniform mat4 ViewMat;
void main()
{
vec4 pos = vec4( position.x, position.y, position.z, 1 );
textureColor = color;
textureCoord = pos.xy;
gl_Position = ProjView * ModelMat * ViewMat * pos;
}
Fragment shader:
#version 410
in vec2 textureCoord;
in vec4 textureColor;
uniform sampler2D texUnit;
out vec4 outputColor;
void main()
{
outputColor = texture( texUnit, textureCoord ) * textureColor;
}
I'm on OSX 10.9, if it matters.