Skip to contentSkip to conversation

setproctitle: fix out of boundary access

PATCH Applied Tobias Stoeckmann 2 participants 2 messages Sep 25, 2017 – Sep 26, 2017

Subsystems (2)
Library code Util-Linux package
lore
Share & tools
lore

Tobias Stoeckmann

author
#0 lore raw

PATCH 1/1 setproctitle: fix out of boundary access

A program using setproctitle can trigger an out of boundary access if an attacker was able to clear the environment before execution.

The check in setproctitle prevents overflows, but does not take into account that the whole length of the arguments could be 1, which is possible by supplying such a program name to execlp(3) or using a symbolic link, e.g. argv[0] = "l", argv[1] = NULL.

Only login uses setproctitle, which is not affected by this problem due to initializing the environment right before the call.

---
 lib/setproctitle.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
lib/setproctitle.c +6 -5
index 93bc82e47..7168e4658 100644
@@ -17,7 +17,7 @@
 extern char **environ;
 
 static char **argv0;
-static int argv_lth;
+static size_t argv_lth;
 
 void initproctitle (int argc, char **argv)
 {

@@ -42,16 +42,17 @@ void initproctitle (int argc, char **argv)
 			return;
 	environ[i] = NULL;
 
-	argv0 = argv;
 	if (i > 0)
-		argv_lth = envp[i-1] + strlen(envp[i-1]) - argv0[0];
+		argv_lth = envp[i-1] + strlen(envp[i-1]) - argv[0];
 	else
-		argv_lth = argv0[argc-1] + strlen(argv0[argc-1]) - argv0[0];
+		argv_lth = argv[argc-1] + strlen(argv[argc-1]) - argv[0];
+	if (argv_lth > 1)
+		argv0 = argv;
 }
 
 void setproctitle (const char *prog, const char *txt)
 {
-        int i;
+        size_t i;
         char buf[SPT_BUFSIZE];
 
         if (!argv0)
Signature · 1 line
2.14.1
maintainer Applied
#1 lore raw
Quoted 2 lines · Tobias Stoeckmann
 lib/setproctitle.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

Applied, thanks.

Signature · 2 lines
 Karel Zak  <[email protected]>
 http://karelzak.blogspot.com