sysfs.c: fix an theoretical issue with snprintf()

Again, code scanners really don't like C string functions, and warn about the potential for a buffer to possibly be too big for a snprintf() call as the checking wasn't quite correct. Fix the check for a buffer overflow up better and handle any potential issues that checking tools could come up with. No real functional change as the sysfs path should be just fine. And really, this is all just userspace code... Signed-off-by: Greg Kroah-Hartman <[email protected]>
gregkh · Oct 22, 2024 · 59f1fe1 · 59f1fe1
1 parent bb1e4b7
commit 59f1fe1
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/sysfs.c b/sysfs.c
@@ -44,8 +44,12 @@ int get_sysfs_name(char *buf, size_t size, libusb_device *dev)
 	}
 
 	len += snprintf(buf, size, "%d-", bnum);
-	for (int i = 0; i < num_pnums; i++)
-		len += snprintf(buf + len, size - len, i ? ".%d" : "%d", pnums[i]);
+	for (int i = 0; i < num_pnums; i++) {
+		int n = snprintf(buf + len, size - len, i ? ".%d" : "%d", pnums[i]);
+		if ((n < 0) || (n >= (int)(size - len)))
+			break;
+		len += n;
+	}
 
 	return len;
 }