AWS KMS InvalidSignatureException when usign correct signature

Question

The sequence of commands I am running is:

$ aws kms sign --key-id 29245e92-1763-4369-871b-d8646e23c40a --message "Hello world!" --signing-algorithm RSASSA_PSS_SHA_256
{
    "KeyId": "arn:aws:kms:eu-west-2:445875827267:key/29245e92-1763-4369-871b-d8646e23c40a",
    "Signature": "T8eYRCTFuigdnHCuYytLscu9EGcdg9UJupPwVB1F3vEENgnkQR37ZPbn5nPr6CTahX+AXTXLFXf8trxRHKoy8997vfuyMaH3RwhFYBDJiAYdJQeBWSyqw5TIwOAnjAYNwJHuX2N8RY2+yKA1vHARNtOiHUesrc/+6eMbaf+ZTJEhY3aIuThW3cjCjnWSoaC44NIMuXfTOVMBhfoKuMW+IZSjH4cCxgj1MaR2sumnCwRW6irTRQOo/NBaxV/8NUWO9RMavDyFpeoxotNGFK0MNhbia4wkady5Dw0orWZSMI30kly66I5ubu+wVgX14GLIiSZofd9Y7RzHmvxL2MTxiQ==",
    "SigningAlgorithm": "RSASSA_PSS_SHA_256"
}

$ aws kms verify --key-id 29245e92-1763-4369-871b-d8646e23c40a --message "Hello world!" --signature T8eYRCTFuigdnHCuYytLscu9EGcdg9UJupPwVB1F3vEENgnkQR37ZPbn5nPr6CTahX+AXTXLFXf8trxRHKoy8997vfuyMaH3RwhFYBDJiAYdJQeBWSyqw5TIwOAnjAYNwJHuX2N8RY2+yKA1vHARNtOiHUesrc/+6eMbaf+ZTJEhY3aIuThW3cjCjnWSoaC44NIMuXfTOVMBhfoKuMW+IZSjH4cCxgj1MaR2sumnCwRW6irTRQOo/NBaxV/8NUWO9RMavDyFpeoxotNGFK0MNhbia4wkady5Dw0orWZSMI30kly66I5ubu+wVgX14GLIiSZofd9Y7RzHmvxL2MTxiQ== --signing-algorithm RSASSA_PSS_SHA_256

An error occurred (KMSInvalidSignatureException) when calling the Verify operation:

Surely this should work? What am I missing here?

Answer 1

Solved from Anon's Comment except need to use fileb:// instead: e.g.

$aws kms verify --key-id 29245e92-1763-4369-871b-d8646e23c40a --message "Hello world!" --signature fileb://raw.sig --signing-algorithm RSASSA_PSS_SHA_256
{
    "KeyId": "arn:aws:kms:eu-west-2:445875827267:key/29245e92-1763-4369-871b-d8646e23c40a",
    "SignatureValid": true,
    "SigningAlgorithm": "RSASSA_PSS_SHA_256"
}