Headers (User-Agent) containing non UTF-8 are not well handled (502 http error) #509
Closed as not planned
Description
In one of my projects, created ages ago (prior to going async) I could handle the issue by myself:
use lambda_http::{
lambda_runtime::Context,
Body, Request, Response,
};
// snipped
// Call handler function based on path
fn run(&self, req: Request, ctx: Context) -> Result<Response<Body>, Error> {
let user_agent = req
.headers()
.get("User-Agent")
.map_or("(no user agent)", |ua| {
ua.to_str().unwrap_or("(non utf-8 user-agent)")
});I could then handle bad headers by simply ignoring them or return a 400 status code.
I should and will upgrade my code to version 0.6.0 but I can check that this is failing still in lambda_runtime even before it is made available for my code.
test.json
{
"requestContext": {
"elb": {
"targetGroupArn": "arn:aws:elasticloadbalancing:region:123456789012:targetgroup/my-target-group/6d0ecf831eec9f09"
}
},
"httpMethod": "OPTIONS",
"path": "",
"queryStringParameters": {},
"headers": {
"accept": "application/json",
"content-type": "application/json",
"host": "my-app-287742195.eu-west-3.elb.amazonaws.com:443",
"user-agent": "Beno\xEEt's User-Agent",
"x-amzn-trace-id": "Root=1-5bdb40ca-556d8b0c50dc66f0511bf520",
"x-forwarded-for": "72.21.198.66",
"x-forwarded-port": "443",
"x-forwarded-proto": "https",
"origin": "example.com"
},
"isBase64Encoded": false,
"body": ""
}Testing the above payload gives the error:
cargo lambda start &
cargo lambda invoke --data-file test.json
Error: Error("invalid escape", line: 14, column: 27)
[Finished running. Exit status: 1]
I could check the same behavior on a real lambda instance to which I sent an actual request and not a crafted payload as above.
curl https://example.com/myaws-fsafs/test --header "User-Agent: Beno`echo -ne '\xEE'`t's User-Agent"