Ensure that the {,v}swprintf functions always null-terminate the

output string, even if an encoding error or malloc failure occurs.

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/libc/stdio/vswprintf.c b/lib/libc/stdio/vswprintf.c
index 023c537..4b1e382 100644
--- a/lib/libc/stdio/vswprintf.c
+++ b/lib/libc/stdio/vswprintf.c
@@ -66,6 +66,7 @@ vswprintf_l(wchar_t * __restrict s, size_t n, locale_t locale,
 	f._bf._base = f._p = (unsigned char *)malloc(128);
 	if (f._bf._base == NULL) {
 		errno = ENOMEM;
+		*s = L'\0';
 		return (-1);
 	}
 	f._bf._size = f._w = 127;		/* Leave room for the NUL */
@@ -74,6 +75,7 @@ vswprintf_l(wchar_t * __restrict s, size_t n, locale_t locale,
 		sverrno = errno;
 		free(f._bf._base);
 		errno = sverrno;
+		*s = L'\0';
 		return (-1);
 	}
 	*f._p = '\0';
@@ -87,6 +89,7 @@ vswprintf_l(wchar_t * __restrict s, size_t n, locale_t locale,
 	free(f._bf._base);
 	if (nwc == (size_t)-1) {
 		errno = EILSEQ;
+		*s = L'\0';
 		return (-1);
 	}
 	if (nwc == n) {