From f52c033e566beafb4480c139eb18662a2870464f Mon Sep 17 00:00:00 2001
From: Philippe Antoine <pantoine@oisf.net>
Date: Tue, 17 Oct 2023 22:01:27 +0200
Subject: [PATCH] pgsql: parse auth message within its bound

If the next PDU is already in the slice next, do not use it and
restrict ourselves to the length of this PDU.
Avoids overconsumption of memory by quadratic complexity, when
having many small PDUS in one big chunk being parsed

Ticket: #6411
---
 rust/src/pgsql/parser.rs | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/rust/src/pgsql/parser.rs b/rust/src/pgsql/parser.rs
index 792fb23a13..4dbb2915c2 100644
--- a/rust/src/pgsql/parser.rs
+++ b/rust/src/pgsql/parser.rs
@@ -719,7 +719,6 @@ fn pgsql_parse_authentication_message<'a>(i: &'a [u8]) -> IResult<&'a [u8], Pgsq
     let (i, identifier) = verify(be_u8, |&x| x == b'R')(i)?;
     let (i, length) = verify(be_u32, |&x| x >= 8)(i)?;
     let (i, auth_type) = be_u32(i)?;
-    let (i, payload) = peek(rest)(i)?;
     let (i, message) = map_parser(
         take(length - 8),
         |b: &'a [u8]| {
@@ -729,14 +728,14 @@ fn pgsql_parse_authentication_message<'a>(i: &'a [u8]) -> IResult<&'a [u8], Pgsq
                                 identifier,
                                 length,
                                 auth_type,
-                                payload: payload.to_vec(),
+                                payload: b.to_vec(),
                             }))),
                 3 => Ok((b, PgsqlBEMessage::AuthenticationCleartextPassword(
                             AuthenticationMessage {
                                 identifier,
                                 length,
                                 auth_type,
-                                payload: payload.to_vec(),
+                                payload: b.to_vec(),
                             }))),
                 5 => {
                     let (b, salt) = all_consuming(take(4_usize))(b)?;
@@ -753,7 +752,7 @@ fn pgsql_parse_authentication_message<'a>(i: &'a [u8]) -> IResult<&'a [u8], Pgsq
                                 identifier,
                                 length,
                                 auth_type,
-                                payload: payload.to_vec(),
+                                payload: b.to_vec(),
                             }))),
                 // TODO - For SASL, should we parse specific details of the challenge itself? (as seen in: https://github.com/launchbadge/sqlx/blob/master/sqlx-core/src/postgres/message/authentication.rs )
                 10 => {
@@ -767,23 +766,21 @@ fn pgsql_parse_authentication_message<'a>(i: &'a [u8]) -> IResult<&'a [u8], Pgsq
                                 })))
                 }
                 11 => {
-                    let (b, sasl_challenge) = rest(i)?;
                     Ok((b, PgsqlBEMessage::AuthenticationSASLContinue(
                                 AuthenticationMessage {
                                     identifier,
                                     length,
                                     auth_type,
-                                    payload: sasl_challenge.to_vec(),
+                                    payload: b.to_vec(),
                                 })))
                 },
                 12 => {
-                    let (i, signature) = take(length - 8)(i)?;
-                    Ok((i, PgsqlBEMessage::AuthenticationSASLFinal(
+                    Ok((b, PgsqlBEMessage::AuthenticationSASLFinal(
                                 AuthenticationMessage {
                                     identifier,
                                     length,
                                     auth_type,
-                                    payload: signature.to_vec(),
+                                    payload: b.to_vec(),
                                 }
                                 )))
                 }
-- 
2.47.2