Given a $0,1$ (binary) integer program of the form:
$$ \begin{array}{lll} \text{min} & f(x) & \\ \text{s.t.} & A x = b \\ & x_i \ge 0 & \quad \forall i\\ & x_i \in \{0,1\} & \quad \forall i \end{array} $$
Note that the size of $A$ is not fixed in either dimension.
I believe this problem has been shown to be hard to approximate (strongly ${\sf NP}$-Complete) by Garey & Johnson. If so, is this still the case when $A, b$ have binary entries and $f(x)$ is a linear function ( $f(x) = \sum_i c_i x_i$ )?