A search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 +/- 0.5 inverse femtobarns collected with the CMS detector in proton-proton collisions at sqrt(s) = 8 TeV. The charged Higgs boson is searched for in top quark decays for m(H+/-) < m(t) - m(b), and in the direct production pp -> t (b) H+/- for m(H+/-) > m(t) - m(b). The H+/- -> tau+/- nu[tau] and H+/- -> t b decay modes in the final states tau[h]+jets, mu tau[h], l+jets, and ll' (l = e, mu) are considered in the search. No signal is observed and 95% confidence level upper limits are set on the charged Higgs boson production. A model-independent upper limit on the product branching fraction B( t -> H+/- b ) B( H+/- -> tau+/- nu[tau] )= 1.2-0.15% is obtained in the mass range m(H+/-) = 80-160 GeV, while the upper limit on the cross section times branching fraction sigma( pp -> t (b) H+/- ) B( H+/- -> tau+/- nu[tau] ) = 0.38-0.025 pb is set in the mass range m(H+/-) = 180-600 GeV. Here, cross section sigma( pp -> t (b) H+/- ) stands for the sum sigma( pp -> t-bar (b) H+ ) + sigma( pp -> t (b-bar) H- ). Assuming B( H+/- -> t b ) = 1, an upper limit on sigma ( pp -> t (b) H+/- ) of 2.0-0.13 pb is set for m(H+/-) = 180-600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the m(H+/-)-tan(beta) parameter space in different MSSM benchmark scenarios.