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Fix ksym buffer overflow on 32 bit platforms #1660

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Fix ksym buffer overflow on 32 bit platforms #1660

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23 changes: 20 additions & 3 deletions info.go
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Original file line number Diff line number Diff line change
Expand Up @@ -185,7 +185,7 @@ type programJitedInfo struct {
// subprograms.
//
// Available from 4.18.
ksyms []uintptr
ksyms []uint64
numKsyms uint32

// insns holds the JITed machine native instructions of the program,
Expand Down Expand Up @@ -344,7 +344,7 @@ func newProgramInfoFromFd(fd *sys.FD) (*ProgramInfo, error) {

if info.NrJitedKsyms > 0 {
pi.jitedInfo.numKsyms = info.NrJitedKsyms
pi.jitedInfo.ksyms = make([]uintptr, info.NrJitedKsyms)
pi.jitedInfo.ksyms = make([]uint64, info.NrJitedKsyms)
info2.JitedKsyms = sys.NewSlicePointer(pi.jitedInfo.ksyms)
info2.NrJitedKsyms = info.NrJitedKsyms
makeSecondCall = true
Expand Down Expand Up @@ -630,8 +630,25 @@ func (pi *ProgramInfo) VerifiedInstructions() (uint32, bool) {
// programs without subprograms (bpf2bpf calls).
//
// The bool return value indicates whether this optional field is available.
//
// When a kernel address can't fit into uintptr (which is usually the case when
// running 32 bit program on a 64 bit kernel), this returns an empty slice and
// a false.
func (pi *ProgramInfo) JitedKsymAddrs() ([]uintptr, bool) {
return pi.jitedInfo.ksyms, len(pi.jitedInfo.ksyms) > 0
ksyms := make([]uintptr, 0, len(pi.jitedInfo.ksyms))
if cap(ksyms) == 0 {
return ksyms, false
}
// Check if a kernel address fits into uintptr (it might not when
// using a 32 bit binary on a 64 bit kernel). This check should work
// with any kernel address, since they have 1s at the highest bits.
if a := pi.jitedInfo.ksyms[0]; uint64(uintptr(a)) != a {
return nil, false
}
for _, ksym := range pi.jitedInfo.ksyms {
ksyms = append(ksyms, uintptr(ksym))
}
return ksyms, true
}

// JitedInsns returns the JITed machine native instructions of the program.
Expand Down