Salah nabbed his fourth goal of the tournament - Egypt's third of Saturday's game in Agadir, Morocco - in the 52nd minute and the Pharaohs needed it as Ivory Coast threatened to twice come back from two goals down.
But Egypt, seeking a record-extending eight title, held on and booked a semi-final date with 2021 champions Senegal in Tangier on Wednesday.
Ivory Coast had a woeful start as Franck Kessie lost the ball in midfield after a poor touch and Odilon Kossounou fell over instead of cutting out Emam Ashour's ball for Omar Marmoush, who scored in the fourth minute.
Ramy Rabia produced a brilliant block to preserve the lead then scored himself with a header from a corner in the 32nd.
Ivory Coast finally pulled one back in the 40th when Ahmed Abou El Fotouh bundled in a dangerous Yan Diomande free kick that Kossounou headed on.
Salah restored Egypt's two-goal cushion early in the second half when Rabia caught the Ivorian defence out with a long ball for Ashour, who set up Salah with the outside of his boot.
Guéla Doué pulled one back again with his heel in a goalmouth scramble after goalkeeper Mohamed El-Shenawy clawed the ball away in the 73rd, but the equaliser never came.
Victor Osimhen scored one goal and set up another for Nigeria to down Algeria 2-0 in Marrakech for their place in the semi-finals.
The Super Eagles, who had a far from ideal preparation with reports of bonuses not being paid, will face hosts Morocco in the second semi in Rabat on Wednesday.
They needed patience against the team with the best defence in the tournament after failing to take their chances in the first half — Akor Adams fired over when he had only Luca Zidane in the Algeria goal to beat, and Calvin Bassey had another effort cleared off the line.
Osimhen finally scored after the break when he headed the ball back across Zidane's direction of movement from Bruno Onyemaechi's cross.
It was the first goal at the tournament conceded by Zidane, whose parents were in the stands again.
But it was quickly followed by the second.
Patient buildup play preceded Alex Iwobi's pass to Osimhen, who unselfishly played across for Adams, who eluded the out-rushing Zidane and poked the ball into the empty net in the 57th.
Algeria coach Vladimir Petković reacted with three changes including the withdrawals of captain Riyad Mahrez and star forward Ibrahim Maza but there was nothing the Fennec Foxes could do to get back in the game against the confident and assured Nigerians, who remained in control throughout.
Three-time champion Nigeria, who lost the final to Ivory Coast in the last edition, are bidding to win the title for the first time since 2013. It would help make up for the disappointment of failing to qualify for the World Cup — in contrast to Algeria.
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