From 29534ad96a84966fc77bef75ef9dcca0ad75685f Mon Sep 17 00:00:00 2001
From: "Todd C. Miller" <Todd.Miller@sudo.ws>
Date: Mon, 19 Aug 2019 08:36:30 -0600
Subject: [PATCH] Fix handling of real-time signals.

---
 lib/util/sig2str.c | 17 +++++++++++++++--
 lib/util/str2sig.c | 35 ++++++++++++++++++++++++-----------
 2 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/lib/util/sig2str.c b/lib/util/sig2str.c
index 23237fa53..6049b1b2c 100644
--- a/lib/util/sig2str.c
+++ b/lib/util/sig2str.c
@@ -62,9 +62,22 @@ int
 sudo_sig2str(int signo, char *signame)
 {
 #if defined(SIGRTMIN) && defined(SIGRTMAX)
-    /* Realtime signal support as per Solaris. */
+    /* Realtime signal support. */
     if (signo >= SIGRTMIN && signo <= SIGRTMAX) {
-	(void)snprintf(signame, SIG2STR_MAX, "RTMIN+%d", (signo - SIGRTMIN));
+	const long rtmax = sysconf(_SC_RTSIG_MAX);
+	if (rtmax > 0) {
+	    if (signo == SIGRTMIN) {
+		strlcpy(signame, "RTMIN", SIG2STR_MAX);
+	    } else if (signo == SIGRTMAX) {
+		strlcpy(signame, "RTMAX", SIG2STR_MAX);
+	    } else if (signo <= SIGRTMIN + (rtmax / 2) - 1) {
+		(void)snprintf(signame, SIG2STR_MAX, "RTMIN+%d",
+		    (signo - SIGRTMIN));
+	    } else {
+		(void)snprintf(signame, SIG2STR_MAX, "RTMAX-%d",
+		    (SIGRTMAX - signo));
+	    }
+	}
 	return 0;
     }
 #endif
diff --git a/lib/util/str2sig.c b/lib/util/str2sig.c
index 236348b6a..68b12c6d2 100644
--- a/lib/util/str2sig.c
+++ b/lib/util/str2sig.c
@@ -36,8 +36,9 @@
 #ifdef HAVE_STRINGS_H
 # include <strings.h>
 #endif /* HAVE_STRINGS_H */
-#include <signal.h>
 #include <ctype.h>
+#include <signal.h>
+#include <unistd.h>
 
 #include "sudo_compat.h"
 
@@ -117,9 +118,14 @@ sudo_str2sig(const char *signame, int *result)
 		return 0;
 	    }
 	    if (signame[5] == '+') {
-		if (signame[6] == '1' || signame[6] == '2' || signame[6] == '3') {
-		    *result = SIGRTMIN + (signame[6] - '0');
-		    return 0;
+		if (isdigit((unsigned char)signame[6])) {
+		    const long rtmax = sysconf(_SC_RTSIG_MAX);
+		    const int off = signame[6] - '0';
+
+		    if (rtmax > 0 && off < rtmax / 2) {
+			*result = SIGRTMIN + off;
+			return 0;
+		    }
 		}
 	    }
 	}
@@ -131,9 +137,14 @@ sudo_str2sig(const char *signame, int *result)
 		return 0;
 	    }
 	    if (signame[5] == '-') {
-		if (signame[6] == '1' || signame[6] == '2' || signame[6] == '3') {
-		    *result = SIGRTMAX - (signame[6] - '0');
-		    return 0;
+		if (isdigit((unsigned char)signame[6])) {
+		    const long rtmax = sysconf(_SC_RTSIG_MAX);
+		    const int off = signame[6] - '0';
+
+		    if (rtmax > 0 && off < rtmax / 2) {
+			*result = SIGRTMAX - off;
+			return 0;
+		    }
 		}
 	    }
 	}
@@ -141,10 +152,12 @@ sudo_str2sig(const char *signame, int *result)
 	break;
     }
 
-    for (signo = 0; signo < NSIG; signo++) {
-	if (strcmp(signame, sudo_sys_signame[signo]) == 0) {
-	    *result = signo;
-	    return 0;
+    for (signo = 1; signo < NSIG; signo++) {
+	if (sudo_sys_signame[signo] != NULL) {
+	    if (strcmp(signame, sudo_sys_signame[signo]) == 0) {
+		*result = signo;
+		return 0;
+	    }
 	}
     }
 
-- 
2.40.0