[PATCH] fmtmsg: verify that label is in the correct format.

[Isaac Dunham <ibid.ag@gmail.com>]

According to POSIX, "the format is two fields separated by a colon.
The first field is up to 10 bytes, the second is up to 14 bytes."
The original implementation assumed that the application provided
a valid label.
---
 src/misc/fmtmsg.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/misc/fmtmsg.c b/src/misc/fmtmsg.c
index 69170b2..956fa5d 100644
--- a/src/misc/fmtmsg.c
+++ b/src/misc/fmtmsg.c
@@ -33,12 +33,20 @@ int fmtmsg(long classification, const char *label, int severity,
 
 	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 
+	if (label) {
+		char *col = strchr(label, ':');
+		i = strlen(label);
+		if (!col || (col-label)>10 || (label+i-col)>15 ||
+		    col==label || label+i-1==col)
+			ret = MM_NOTOK;
+	}
+
 	if (severity == MM_HALT) errstring = "HALT: ";
 	else if (severity == MM_ERROR) errstring = "ERROR: ";
 	else if (severity == MM_WARNING) errstring = "WARNING: ";
 	else if (severity == MM_INFO) errstring = "INFO: ";
 
-	if (classification & MM_CONSOLE) {
+	if (!ret && classification & MM_CONSOLE) {
 		consolefd = open("/dev/console", O_WRONLY);
 		if (consolefd < 0) {
 			ret = MM_NOCON;
@@ -54,7 +62,7 @@ int fmtmsg(long classification, const char *label, int severity,
 		}
 	}
 
-	if (classification & MM_PRINT) {
+	if (ret != MM_NOTOK && classification & MM_PRINT) {
 		while (cmsg && cmsg[0]) {
 			for(i=0; msgs[i]; i++) {
 				if (!_strcolcmp(msgs[i], cmsg)) break;
-- 
2.3.6