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bug#10904: 24.0.93; Infinite loop in GnuTLS code during Gnus nnimap-init
From: |
Ted Zlatanov |
Subject: |
bug#10904: 24.0.93; Infinite loop in GnuTLS code during Gnus nnimap-initiated SSL handshake |
Date: |
Sun, 08 Apr 2012 20:37:32 -0400 |
User-agent: |
Gnus/5.130004 (Ma Gnus v0.4) Emacs/24.0.95 (gnu/linux) |
On Sun, 08 Apr 2012 13:46:56 -0400 Thomas Fitzsimmons <fitzsim@fitzsim.org>
wrote:
TF> The loop happens when the GnuTLS handshake fails for some reason, within
TF> a network process. I use the attached patch to limit the number of
TF> iterations. I'm not familiar enough with the Emacs process code to
TF> suggest a fix though.
Thanks again for the help and provided patch. I modified it to keep the
number of handshakes tried per connection, not globally. Please try
it. I will also propose it on emacs-devel for inclusion in the upcoming
24.1 release.
Ted
=== modified file 'src/gnutls.c'
--- src/gnutls.c 2012-02-13 20:39:46 +0000
+++ src/gnutls.c 2012-04-09 00:34:32 +0000
@@ -259,6 +259,12 @@
message ("gnutls.c: [%d] %s %s", level, string, extra);
}
+static void
+gnutls_log_function2i (int level, const char* string, int extra)
+{
+ message ("gnutls.c: [%d] %s %d", level, string, extra);
+}
+
static int
emacs_gnutls_handshake (struct Lisp_Process *proc)
{
@@ -399,10 +405,22 @@
ssize_t rtnval;
gnutls_session_t state = proc->gnutls_state;
+ int log_level = proc->gnutls_log_level;
+
if (proc->gnutls_initstage != GNUTLS_STAGE_READY)
{
- emacs_gnutls_handshake (proc);
- return -1;
+ if (proc->gnutls_handshakes_tried < GNUTLS_EMACS_HANDSHAKES_LIMIT)
+ {
+ proc->gnutls_handshakes_tried++;
+ emacs_gnutls_handshake (proc);
+ GNUTLS_LOG2i (5, log_level, "Retried handshake",
+ proc->gnutls_handshakes_tried);
+ return -1;
+ }
+
+ GNUTLS_LOG (2, log_level, "Giving up on handshake; resetting retries");
+ proc->gnutls_handshakes_tried = 0;
+ return 0;
}
rtnval = fn_gnutls_record_recv (state, buf, nbyte);
if (rtnval >= 0)
=== modified file 'src/gnutls.h'
--- src/gnutls.h 2012-01-05 09:46:05 +0000
+++ src/gnutls.h 2012-04-09 00:29:27 +0000
@@ -23,6 +23,8 @@
#include <gnutls/gnutls.h>
#include <gnutls/x509.h>
+#define GNUTLS_EMACS_HANDSHAKES_LIMIT 100
+
typedef enum
{
/* Initialization stages. */
@@ -53,6 +55,8 @@
#define GNUTLS_LOG2(level, max, string, extra) do { if (level <= max) {
gnutls_log_function2 (level, "(Emacs) " string, extra); } } while (0)
+#define GNUTLS_LOG2i(level, max, string, extra) do { if (level <= max) {
gnutls_log_function2i (level, "(Emacs) " string, extra); } } while (0)
+
extern EMACS_INT
emacs_gnutls_write (struct Lisp_Process *proc, const char *buf, EMACS_INT
nbyte);
extern EMACS_INT
=== modified file 'src/process.c'
--- src/process.c 2012-03-23 12:23:14 +0000
+++ src/process.c 2012-04-09 00:24:07 +0000
@@ -641,6 +641,7 @@
#ifdef HAVE_GNUTLS
p->gnutls_initstage = GNUTLS_STAGE_EMPTY;
p->gnutls_log_level = 0;
+ p->gnutls_handshakes_tried = 0;
p->gnutls_p = 0;
p->gnutls_state = NULL;
p->gnutls_x509_cred = NULL;
=== modified file 'src/process.h'
--- src/process.h 2012-01-19 07:21:25 +0000
+++ src/process.h 2012-04-09 00:23:24 +0000
@@ -134,6 +134,7 @@
gnutls_certificate_client_credentials gnutls_x509_cred;
gnutls_anon_client_credentials_t gnutls_anon_cred;
int gnutls_log_level;
+ int gnutls_handshakes_tried;
int gnutls_p;
#endif
};