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sws_getcachedcontext

API Overview​

sws_getCachedContext is an API in ffmpeg. This rule belongs to the api pair type. This rule is generated using ChatDetector.

Rule Description​

tip

Parameter 1 of sws_getCachedContext must be released by calling sws_freeContext, with the same object passed as the 1-th argument to sws_freeContext

info
  • Tags: api pair
  • Parameter Index: 0
  • CWE Type: CWE-404

Rule Code​

import cpp
import semmle.code.cpp.dataflow.new.DataFlow


DataFlow::Node getSource(FunctionCall fc){
  fc.getTarget().hasName("sws_getCachedContext")
  and result.asExpr() = fc.getArgument(0)
}

DataFlow::Node getSink(FunctionCall fc){
  fc.getTarget().hasName("sws_freeContext")
  and result.asExpr() = fc.getArgument(0)
}

FunctionCall freeTarget(FunctionCall malloc){
  DataFlow::localFlow(getSource(malloc), getSink(result))
}

from FunctionCall fc
where fc.getTarget().hasName("sws_getCachedContext")
      and not exists(
        FunctionCall free| 
        free = freeTarget(fc)
      )
select fc.getLocation()