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Don't assert when parsing a CommitmentTreeWitness

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This commit is contained in:
Jack Grigg 2019-03-19 22:10:34 +13:00
parent 9b4186705a
commit 98d7621135
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GPG Key ID: 9E8255172BBF9898
1 changed files with 19 additions and 12 deletions
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31
zcash_primitives/src/merkle_tree.rs
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@ -436,9 +436,11 @@ impl CommitmentTreeWitness {
} }
pub fn from_slice_with_depth(mut witness: &[u8], depth: usize) -> Result<Self, ()> { pub fn from_slice_with_depth(mut witness: &[u8], depth: usize) -> Result<Self, ()> {
// Skip the first byte, which should be "32" to signify the length of // Skip the first byte, which should be "depth" to signify the length of
// the following vector of Pedersen hashes. // the following vector of Pedersen hashes.
assert_eq!(witness[0], depth as u8); if witness[0] != depth as u8 {
return Err(());
}
witness = &witness[1..]; witness = &witness[1..];
// Begin to construct the authentication path // Begin to construct the authentication path
@ -447,7 +449,9 @@ impl CommitmentTreeWitness {
// The vector works in reverse // The vector works in reverse
for i in (0..depth).rev() { for i in (0..depth).rev() {
// skip length of inner vector // skip length of inner vector
assert_eq!(witness[0], 32); // the length of a pedersen hash if witness[0] != 32 { // the length of a pedersen hash
return Err(());
}
witness = &witness[1..]; witness = &witness[1..];
// Grab the sibling node at this depth in the tree // Grab the sibling node at this depth in the tree
@ -472,9 +476,10 @@ impl CommitmentTreeWitness {
} }
// Read the position from the witness // Read the position from the witness
let position = witness let position = match witness.read_u64::<LittleEndian>() {
.read_u64::<LittleEndian>() Ok(pos) => pos,
.expect("should have had index at the end"); Err(_) => return Err(()),
};
// Given the position, let's finish constructing the authentication // Given the position, let's finish constructing the authentication
// path // path
@ -488,12 +493,14 @@ impl CommitmentTreeWitness {
// The witness should be empty now; if it wasn't, the caller would // The witness should be empty now; if it wasn't, the caller would
// have provided more information than they should have, indicating // have provided more information than they should have, indicating
// a bug downstream // a bug downstream
assert_eq!(witness.len(), 0); if witness.is_empty() {
Ok(CommitmentTreeWitness {
Ok(CommitmentTreeWitness { auth_path,
auth_path, position,
position, })
}) } else {
Err(())
}
} }
} }