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swf: avm1: Ignore bad ActionTry opcodes and bad ConstantPool strings #11957

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Merged
merged 2 commits into from
Jul 15, 2023
Merged

swf: avm1: Ignore bad ActionTry opcodes and bad ConstantPool strings #11957

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a001519
swf: Ignore bad ActionTry opcodes
Lord-McSweeney Jul 8, 2023
d592f66
swf: Ignore bad ConstantPool string reads
Lord-McSweeney Jul 8, 2023
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14 changes: 13 additions & 1 deletion swf/src/avm1/read.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -207,7 +207,10 @@ impl<'a> Reader<'a> {
let count = self.read_u16()?;
let mut strings = Vec::with_capacity(count as usize);
for _ in 0..count {
strings.push(self.read_str()?);
let string = self.read_str();
if let Ok(string) = string {
strings.push(string);
}
}
Ok(ConstantPool { strings })
}
Expand Down Expand Up @@ -350,6 +353,15 @@ impl<'a> Reader<'a> {
}

fn read_try(&mut self, length: &mut usize) -> Result<Try<'a>> {
// All Try opcodes must be at least 7 bytes long. If it's shorter, it's a bogus opcode; return an empty Try.
if *length < 7 {
return Ok(Try {
try_body: &[],
catch_body: None,
finally_body: None,
});
}

let flags = TryFlags::from_bits_truncate(self.read_u8()?);
let try_size: usize = self.read_u16()?.into();
let catch_size: usize = self.read_u16()?.into();
Expand Down