fix: pad Poseidon hashv inputs to 32 bytes for syscall compatibility (#2373)

Solana mainnet now enforces all Poseidon syscall inputs to be exactly
32 bytes. Left-pad sub-32-byte inputs inside Poseidon::hashv() right
before the syscall/library call. This preserves field element values
(leading BE zeros are a no-op) and keeps AsByteVec and #[truncate]
backwards compatible.

Bumps light-hasher 1.1.0 -> 1.1.1, light-sdk 0.11.0 -> 0.11.1.

Author: ananas-block

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "light-hasher"
-version = "1.1.0"
+version = "1.1.1"
 description = "Trait for generic usage of hash functions on Solana"
 repository = "https://github.com/Lightprotocol/light-protocol"
 license = "Apache-2.0"

merkle-tree/hasher/Cargo.toml

@@ -12,6 +12,8 @@ pub enum HasherError {
     PoseidonSyscall(#[from] PoseidonSyscallError),
     #[error("Unknown Solana syscall error: {0}")]
     UnknownSolanaSyscall(u64),
+    #[error("Input length {0} exceeds maximum of {1} bytes")]
+    InputTooLarge(usize, usize),
 }
 
 // NOTE(vadorovsky): Unfortunately, we need to do it by hand. `num_derive::ToPrimitive`
@@ -23,6 +25,7 @@ impl From<HasherError> for u32 {
             HasherError::Poseidon(_) => 7002,
             HasherError::PoseidonSyscall(e) => (u64::from(e)).try_into().unwrap_or(7003),
             HasherError::UnknownSolanaSyscall(e) => e.try_into().unwrap_or(7004),
+            HasherError::InputTooLarge(_, _) => 7005,
         }
     }
 }

merkle-tree/hasher/src/errors.rs

@@ -14,6 +14,22 @@ impl Hasher for Poseidon {
     }
 
     fn hashv(vals: &[&[u8]]) -> Result<Hash, HasherError> {
+        // Poseidon syscall requires exactly 32-byte inputs.
+        // Leading zeros preserve big-endian field element values.
+        let padded_bufs: Vec<[u8; 32]> = vals
+            .iter()
+            .map(|v| {
+                if v.len() > 32 {
+                    return Err(HasherError::InputTooLarge(v.len(), 32));
+                }
+                let mut buf = [0u8; 32];
+                buf[32 - v.len()..].copy_from_slice(v);
+                Ok(buf)
+            })
+            .collect::<Result<Vec<_>, _>>()?;
+        let vals: Vec<&[u8]> = padded_bufs.iter().map(|b| b.as_slice()).collect();
+        let vals: &[&[u8]] = vals.as_slice();
+
         // Perform the calculation inline, calling this from within a program is
         // not supported.
         #[cfg(not(target_os = "solana"))]

merkle-tree/hasher/src/poseidon.rs

@@ -1,6 +1,6 @@
 [package]
 name = "light-sdk"
-version = "0.11.0"
+version = "0.11.1"
 description = "Rust SDK for ZK Compression on Solana"
 repository = "https://github.com/Lightprotocol/light-protocol"
 license = "Apache-2.0"
@@ -37,7 +37,7 @@ aligned-sized = { version = "1.1.0", path = "../macros/aligned-sized" }
 light-macros = { version = "1.1.0", path = "../macros/light" }
 light-sdk-macros = { version = "0.4.0", path = "../macros/light-sdk-macros" }
 bytemuck = "1.17"
-light-hasher = { version = "1.1.0", path = "../merkle-tree/hasher", features=["solana"] }
+light-hasher = { version = "1.1.1", path = "../merkle-tree/hasher", features=["solana"] }
 light-heap = { version = "1.1.0", path = "../heap", optional = true }
 light-indexed-merkle-tree = { workspace = true }
 account-compression = { workspace = true , optional = true }