Stop the War, a pacifist coalition once chaired by Corbyn, has called a demonstration outside the British parliament on Monday to protest about the strikes.
Mr Johnson said the United Kingdom has to "take every possible precaution" to prepare for possible revenge cyber attacks on targets such as the NHS and electrical facilities. "The opposition does not operate helicopters or use barrel bombs".
The government's legal position, drawn up with the advice of the attorney-general, Jeremy Wright, and presented to cabinet ministers last Wednesday, said force was justified to alleviate "overwhelming humanitarian suffering". However, that has been less the case in recent years.
May is not obliged to win parliament's approval before ordering military action, but a non-binding constitutional convention to do so has been established since a 2003 vote on joining the US -led invasion of Iraq.
Lawmakers backed action in Iraq in 2014, and again in Syria in 2015, strictly limiting strikes in both countries to targets of the Islamic State jihadist group.
British jets fired missiles at a Syrian military base suspected of holding chemical weapons ingredients on Saturday in Britain's first military action against President Bashar al-Assad's regime.
The Prime Minister is expected to face anger in the Commons after launching military action without securing the support of Parliament.More news: Shire to Sell Oncology Unit for $2.4 Billion to Servier
Theresa May will face MPs over her decision to launch air strikes against Syria as Labour questioned the legality of the bombing raid.
"We are prepared to sustain this response until the Syrian regime stops its use of prohibited chemical agents", the U.S. president said in a televised address. The strikes at 0100 GMT were 15 miles (24 kilometres) west of Homs.
"I believe that the action taken will have significantly degraded the Syrian regime's ability to use chemical weapons", she said.
"It is about a limited and targeted strike that does not further escalate tensions in the region and that does everything possible to prevent civilian casualties", she said.
Peter Felstead, editor of Jane's Defence Weekly, said he did not think May would face a "serious backlash", as the strikes ultimately were politically and operationally "the right thing to do".
"And we can not wait to alleviate further humanitarian suffering caused by chemical weapons attacks".