commit e94ce889f011b15f7f98b16ae4ddb2123c7c9b0f
author Vadim Yanitskiy <axilirator@gmail.com> Sat Apr 06 20:01:43 2019 +0700
committer Harald Welte <laforge@gnumonks.org> Mon Apr 08 07:30:45 2019 +0000
tree a152cdfa43b6eae6b1389ec44662b8316c321965
parent c53ca915943e29207e40abc79f72ae6a16f3ed66

ipaccess-config: use POSIX regex for Unit ID format check

Instead of counting digits and slashes of the IPA Unit ID manually,
use POSIX regex functions, so the code is easier to maintain and
read. As a bonus, this fixes CID#188854: variable 'remain_slash'
was of type 'uint8_t', so it could never be lower than zero.

Change-Id: Id613bf650833dd38eaad08fdfffdf8dbe2f002b1
Related: CID#188854 Unsigned integer overflow

src/ipaccess/ipaccess-config.c

diff --git a/src/ipaccess/ipaccess-config.c b/src/ipaccess/ipaccess-config.c
index da19ce2..54e4efd 100644
--- a/src/ipaccess/ipaccess-config.c
+++ b/src/ipaccess/ipaccess-config.c
@@ -27,6 +27,7 @@
 #include <getopt.h>
 #include <errno.h>
 #include <ctype.h>
+#include <regex.h>
 #include <inttypes.h>
 #include <sys/fcntl.h>
 #include <sys/stat.h>
@@ -842,33 +843,20 @@
 
 static bool check_unitid_fmt(const char* unit_id)
 {
-	const char *p = unit_id;
-	bool must_digit = true;
-	uint8_t remain_slash = 2;
+	regex_t regexp;
+	int rc;
 
 	if (strlen(unit_id) < 5)
 		goto wrong_fmt;
 
-	while (*p != '\0') {
-		if (*p != '/' && !isdigit(*p))
-			goto wrong_fmt;
-		if (*p == '/' && must_digit)
-			goto wrong_fmt;
-		if (*p == '/') {
-			must_digit = true;
-			remain_slash--;
-			if (remain_slash < 0)
-				goto wrong_fmt;
-		} else {
-			must_digit = false;
-		}
-		p++;
-	}
+	rc = regcomp(&regexp, "^[0-9]+/[0-9]+/[0-9]+$", REG_EXTENDED | REG_NOSUB);
+	OSMO_ASSERT(!rc);
 
-	if (*(p-1) == '/')
-		goto wrong_fmt;
+	rc = regexec(&regexp, unit_id, 0, NULL, 0);
+	regfree(&regexp);
 
-	return true;
+	if (rc == 0)
+		return true;
 
 wrong_fmt:
 	fprintf(stderr, "ERROR: unit-id wrong format. Must be '\\d+/\\d+/\\d+'\n");