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From 7f4a743171f9e6b283207d448de6562219774fbf Mon Sep 17 00:00:00 2001
From: Salvatore Bonaccorso <carnil@debian.org>
Date: Tue, 25 Jun 2024 12:24:29 +0100
Subject: Disable async-signal-unsafe code from the sshsigdie() function
Address signal handler race condition: if a client does not authenticate
within LoginGraceTime seconds (120 by default, 600 in old OpenSSH
versions), then sshd's SIGALRM handler is called asynchronously, but
this signal handler calls various functions that are not
async-signal-safe (for example, syslog()).
This is a regression from CVE-2006-5051 ("Signal handler race condition
in OpenSSH before 4.4 allows remote attackers to cause a denial of
service (crash), and possibly execute arbitrary code")
Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
Patch-Name: sshsigdie-async-signal-unsafe.patch
---
log.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/log.c b/log.c
index 6a8b1fc4a..57256660f 100644
--- a/log.c
+++ b/log.c
@@ -452,12 +452,14 @@ void
sshsigdie(const char *file, const char *func, int line, int showfunc,
LogLevel level, const char *suffix, const char *fmt, ...)
{
+#if 0
va_list args;
va_start(args, fmt);
sshlogv(file, func, line, showfunc, SYSLOG_LEVEL_FATAL,
suffix, fmt, args);
va_end(args);
+#endif
_exit(1);
}
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