Sorry, I forgot to remove silly debugging code.
Attaching the *proper* patch.
Kind regards,
Krzysztof Piecuch
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‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, August 26, 2019 6:50 PM, Krzysztof Piecuch <piec...@protonmail.com>
wrote:
> Hello,
>
> I'm attaching a small patch to ftpfs. This fixes:
> * ftpfs null pointer dereference when provided with an invalid hostname
> * gethostbyname_r invocation
>
> Thank you,
> Chris
From 0c87f704a0355f3732d82d9703d7449f55436876 Mon Sep 17 00:00:00 2001
From: Krzysztof Piecuch <piec...@protonmail.com>
Date: Mon, 26 Aug 2019 13:43:18 -0400
Subject: [PATCH] ftpfs: fix host lookup error handling
---
ftpfs/host.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/ftpfs/host.c b/ftpfs/host.c
index cd6fd4c0..ba1689b1 100644
--- a/ftpfs/host.c
+++ b/ftpfs/host.c
@@ -101,7 +101,10 @@ split_server_name (const char *server, char **host, char **user, char **passwd)
error_t
lookup_server (const char *server, struct ftp_conn_params **params, int *h_err)
{
- char hostent_data[2048]; /* XXX what size should this be???? */
+ size_t bufsize = 64;
+ const size_t bufsizemax = 4096;
+ int retval;
+ char *hostent_data = NULL;
struct hostent _he, *he;
char *host, *user, *passwd;
error_t err = split_server_name (server, &host, &user, &passwd);
@@ -114,8 +117,16 @@ lookup_server (const char *server, struct ftp_conn_params **params, int *h_err)
thread could have inserted a duplicate entry for the same host name, but
this isn't really a problem, just annoying. */
- if (gethostbyname_r (host, &_he, hostent_data, sizeof hostent_data,
- &he, h_err) == 0)
+ do {
+ bufsize *= 2;
+ hostent_data = realloc(hostent_data, bufsize);
+ if (!hostent_data)
+ err = ENOMEM;
+ retval = gethostbyname_r (host, &_he, hostent_data, bufsize,
+ &he, h_err);
+ } while (!err && retval == ERANGE && bufsize < bufsizemax);
+
+ if (retval == 0 && he)
{
*params = malloc (sizeof (struct ftp_conn_params));
if (! *params)
@@ -143,6 +154,7 @@ lookup_server (const char *server, struct ftp_conn_params **params, int *h_err)
err = EINVAL;
free (host);
+ free (hostent_data);
if (err)
{
--
2.20.1
