fix (normal, narrow) printf erroneously processing %n after output errors

[musl] / src / stdio / vfprintf.c

diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c
index 4555795..2dbdb5e 100644 (file)
--- a/src/stdio/vfprintf.c
+++ b/src/stdio/vfprintf.c
@@ -530,6 +530,9 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
 
                if (!f) continue;
 
+               /* Do not process any new directives once in error state. */
+               if (ferror(f)) return -1;
+
                z = buf + sizeof(buf);
                prefix = "-+   0X0x";
                pl = 0;