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melib/nntp: limit LIST ACTIVE command length to 512 octets 

According to RFC 3977:

> Command lines MUST NOT exceed 512 octets, which includes the
> terminating CRLF pair

Sending a `LIST ACTIVE` command with lots of newgroups and passing the
512 byte limit is therefore invalid. This commit splits the mailboxes in
chunks and sends a separate command for each maximal chunk that has
a valid length.

Fixes #269.

Reported-by: r3k2
pull/270/head
Manos Pitsidianakis 2023-08-10 18:30:59 +03:00
parent 40d4ecefa0
commit 4e654d2d02
Signed by: Manos Pitsidianakis
GPG Key ID: 7729C7707F7E09D0
1 changed files with 54 additions and 28 deletions
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82
melib/src/nntp/mod.rs
View File

@ -731,39 +731,65 @@ impl NntpType {
pub async fn nntp_mailboxes(connection: &Arc<FutureMutex<NntpConnection>>) -> Result<()> {
let mut res = String::with_capacity(8 * 1024);
let mut conn = connection.lock().await;
let command = {
let mut mailboxes = {
let mailboxes_lck = conn.uid_store.mailboxes.lock().await;
mailboxes_lck
.values()
.fold("LIST ACTIVE ".to_string(), |mut acc, x| {
if acc.len() != "LIST ACTIVE ".len() {
acc.push(',');
}
acc.push_str(x.name());
acc
})
.map(|m| m.name().to_string())
.collect::<SmallVec<[String; 16]>>()
};
conn.send_command(command.as_bytes()).await?;
conn.read_response(&mut res, true, &["215 "])
.await
.chain_err_summary(|| {
format!(
"Could not get newsgroups {}: expected LIST ACTIVE response but got: {}",
&conn.uid_store.account_name, res
)
})?;
debug!(&res);
let mut mailboxes_lck = conn.uid_store.mailboxes.lock().await;
for l in res.split_rn().skip(1) {
let s = l.split_whitespace().collect::<SmallVec<[&str; 4]>>();
if s.len() != 3 {
continue;
mailboxes.reverse();
while !mailboxes.is_empty() {
let mut command = "LIST ACTIVE ".to_string();
'batch: while let Some(m) = mailboxes.pop() {
/* first check if the group name itself is too big for `LIST ACTIVE`. */
if "LIST ACTIVE ".len() + m.len() + "\r\n".len() >= 512 {
log::warn!(
"{}: Newsgroup named {} has a name that exceeds RFC 3977 limits of \
maximum command lines (512 octets) with LIST ACTIVE. Skipping it.",
&conn.uid_store.account_name,
m
);
continue 'batch;
}
if command.len() != "LIST ACTIVE ".len() {
command.push(',');
}
// RFC 3977
// 3. Basic Concepts
// 3.1. Commands and Responses
// Command lines MUST NOT exceed 512 octets, which includes the terminating CRLF
// pair.
if command.len() + m.len() + "\r\n".len() >= 512 {
mailboxes.push(m);
if command.ends_with(',') {
command.pop();
}
break 'batch;
}
command.push_str(&m);
}
conn.send_command(command.as_bytes()).await?;
conn.read_response(&mut res, true, &["215 "])
.await
.chain_err_summary(|| {
format!(
"Could not get newsgroups {}: expected LIST ACTIVE response but got: {}",
&conn.uid_store.account_name, res
)
})?;
let mut mailboxes_lck = conn.uid_store.mailboxes.lock().await;
for l in res.split_rn().skip(1) {
let s = l.split_whitespace().collect::<SmallVec<[&str; 4]>>();
if s.len() != 3 {
continue;
}
let mailbox_hash = MailboxHash(get_path_hash!(&s[0]));
mailboxes_lck.entry(mailbox_hash).and_modify(|m| {
*m.high_watermark.lock().unwrap() = usize::from_str(s[1]).unwrap_or(0);
*m.low_watermark.lock().unwrap() = usize::from_str(s[2]).unwrap_or(0);
});
}
let mailbox_hash = MailboxHash(get_path_hash!(&s[0]));
mailboxes_lck.entry(mailbox_hash).and_modify(|m| {
*m.high_watermark.lock().unwrap() = usize::from_str(s[1]).unwrap_or(0);
*m.low_watermark.lock().unwrap() = usize::from_str(s[2]).unwrap_or(0);
});
}
Ok(())
}