From 83da7e926c6b5d728cee35415f6a79510fb853c9 Mon Sep 17 00:00:00 2001
From: Zdenek Dohnal <zdohnal@redhat.com>
Date: Tue, 10 Mar 2026 13:00:32 +0100
Subject: [PATCH] RHEL-154276 endless poll loop in http_write when POLLHUP is
 returned

Resolves: RHEL-154276
---
 ...not-check-for-errno-after-I-O-operat.patch | 44 +++++++++++++++++++
 cups.spec                                     |  9 +++-
 2 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 0001-tls-gnutls.c-Do-not-check-for-errno-after-I-O-operat.patch

diff --git a/0001-tls-gnutls.c-Do-not-check-for-errno-after-I-O-operat.patch b/0001-tls-gnutls.c-Do-not-check-for-errno-after-I-O-operat.patch
new file mode 100644
index 0000000..1ddfebd
--- /dev/null
+++ b/0001-tls-gnutls.c-Do-not-check-for-errno-after-I-O-operat.patch
@@ -0,0 +1,44 @@
+From e2419c698922fb65ef62250a4588104021449b55 Mon Sep 17 00:00:00 2001
+From: Zdenek Dohnal <zdohnal@redhat.com>
+Date: Fri, 6 Mar 2026 08:31:47 +0100
+Subject: [PATCH] tls-gnutls.c: Do not check for errno after I/O operations
+
+Based on gnutls_record_send/recv man pages, we should use the return
+value of the functions as indicator what happened in the function and do
+not look into errno at all.
+
+Checking the errno value caused infinity loop in cupsd on busy servers
+if there were enough connection errors when cupsd wrote the response.
+
+The patch is provided by Paul Zirnik from SUSE - thank you for the
+patch!
+
+Fixes #827
+---
+ cups/tls-gnutls.c | 4 ++--
+
+diff --git a/cups/tls-gnutls.c b/cups/tls-gnutls.c
+index 64f2af372..5769d6313 100644
+--- a/cups/tls-gnutls.c
++++ b/cups/tls-gnutls.c
+@@ -1208,7 +1208,7 @@ _httpTLSRead(http_t *http,		/* I - Connection to server */
+ 
+   result = gnutls_record_recv(http->tls, buf, (size_t)len);
+ 
+-  if (result < 0 && !errno)
++  if (result < 0)
+   {
+    /*
+     * Convert GNU TLS error to errno value...
+@@ -1669,7 +1669,7 @@ _httpTLSWrite(http_t     *http,		/* I - Connection to server */
+ 
+   result = gnutls_record_send(http->tls, buf, (size_t)len);
+ 
+-  if (result < 0 && !errno)
++  if (result < 0)
+   {
+    /*
+     * Convert GNU TLS error to errno value...
+-- 
+2.53.0
+
diff --git a/cups.spec b/cups.spec
index ca4896c..0545e5f 100644
--- a/cups.spec
+++ b/cups.spec
@@ -22,7 +22,7 @@ Summary: CUPS printing system
 Name: cups
 Epoch: 1
 Version: 2.4.10
-Release: 16%{?dist}
+Release: 17%{?dist}
 # backend/failover.c - BSD-3-Clause
 # cups/md5* - Zlib
 # scheduler/colorman.c - Apache-2.0 WITH LLVM-exception AND BSD-2-Clause
@@ -127,6 +127,8 @@ Patch1021: 0001-conf.c-Fix-stopping-scheduler-on-unknown-directive.patch
 # fix use-after-free reported after fix for CVE-2025-58436
 # https://github.com/OpenPrinting/cups/pull/1454
 Patch1022: 0001-scheduler-Fix-possible-use_after_free-in-cupsdReadCl.patch
+# RHEL-154276 endless poll loop in http_write when POLLHUP is returned
+Patch1023: 0001-tls-gnutls.c-Do-not-check-for-errno-after-I-O-operat.patch
 
 
 ##### Patches removed because IMHO they aren't no longer needed
@@ -401,6 +403,8 @@ to CUPS daemon. This solution will substitute printer drivers and raw queues in
 %patch -P 1021 -p1 -b .ignore-unknown
 # fix use-after-free reported after fix for CVE-2025-58436
 %patch -P 1022 -p1 -b .osh-use-after-free
+# RHEL-154276 endless poll loop in http_write when POLLHUP is returned
+%patch -P 1023 -p1 -b .http-endless-poll-loop
 
 
 # Log to the system journal by default (bug #1078781, bug #1519331).
@@ -872,6 +876,9 @@ rm -f %{cups_serverbin}/backend/smb
 %{_mandir}/man7/ippeveps.7.gz
 
 %changelog
+* Mon Mar 09 2026 Zdenek Dohnal <zdohnal@redhat.com> - 1:2.4.10-17
+- RHEL-154276 endless poll loop in http_write when POLLHUP is returned
+
 * Fri Dec 12 2025 Zdenek Dohnal <zdohnal@redhat.com> - 1:2.4.10-16
 - fix use-after-free reported by OSH