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fix: mem cache out of range panic caused by overflow #3761

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merged 1 commit into from
Jul 1, 2024
Merged

fix: mem cache out of range panic caused by overflow #3761

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11 changes: 10 additions & 1 deletion pkg/proc/mem.go
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,12 @@ type memCache struct {
}

func (m *memCache) contains(addr uint64, size int) bool {
return addr >= m.cacheAddr && addr <= (m.cacheAddr+uint64(len(m.cache)-size))
end := addr + uint64(size)
if end < addr {
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This branch is never exercised by any test. Can you add a case for it?

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Done, please take a look again.

// overflow
return false
}
return addr >= m.cacheAddr && end <= m.cacheAddr+uint64(len(m.cache))
}

func (m *memCache) ReadMemory(data []byte, addr uint64) (n int, err error) {
Expand Down Expand Up @@ -69,6 +74,10 @@ func cacheMemory(mem MemoryReadWriter, addr uint64, size int) MemoryReadWriter {
if size <= 0 {
return mem
}
if addr+uint64(size) < addr {
// overflow
return mem
}
switch cacheMem := mem.(type) {
case *memCache:
if cacheMem.contains(addr, size) {
Expand Down
20 changes: 20 additions & 0 deletions pkg/proc/proc_general_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,26 @@ func TestIssue554(t *testing.T) {
}
}

func TestIssue3760(t *testing.T) {
// unsigned integer overflow if len(m.cache) < size
mem := memCache{true, 0x20, make([]byte, 100), nil}
if mem.contains(0x20, 200) {
t.Fatalf("should be false")
}
// test overflow of end addr
mem = memCache{true, 0xfffffffffffffff0, make([]byte, 15), nil}
if !mem.contains(0xfffffffffffffff0, 15) {
t.Fatalf("should contain it")
}
if mem.contains(0xfffffffffffffff0, 16) {
t.Fatalf("shoud be false")
}
cm := cacheMemory(nil, 0xffffffffffffffff, 1)
if cm != nil {
t.Fatalf("should be nil")
}
}

type dummyMem struct {
t *testing.T
mem []byte
Expand Down