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| author | Mark H Weaver <mhw@netris.org> | 2019-04-01 22:11:35 -0400 |
|---|---|---|
| committer | Andy Wingo <wingo@pobox.com> | 2019-05-23 17:40:08 +0200 |
| commit | 980d8265c2dc35d6e02e540c9041cbf0975dfede (patch) | |
| tree | 067f18effb6989e30fa872310ff3bddd920a8ac8 /libguile/bytevectors.c | |
| parent | b38d9a1527a9d796034bf721c9a266d261db5ad0 (diff) | |
| download | guile-980d8265c2dc35d6e02e540c9041cbf0975dfede.tar.gz | |
Avoid passing NULL to 'memcpy' and 'memcmp'.
Reported by Jeffrey Walton <noloader@gmail.com> in
<https://lists.gnu.org/archive/html/guile-devel/2019-03/msg00001.html>.
Note that C11 section 7.1.4 (Use of library functions) states that:
"unless explicitly stated otherwise in the detailed descriptions [of
library functions] that follow: If an argument to a function has an
invalid value (such as ... a null pointer ...) ..., the behavior is
undefined." Note that 'strxfrm' is an example of a standard C function
that explicitly states otherwise, allowing NULL to be passed in the
first argument if the size argument is zero, but no similar allowance is
specified for 'memcpy' or 'memcmp'.
* libguile/bytevectors.c (scm_uniform_array_to_bytevector): Call memcpy
only if 'byte_len' is non-zero.
* libguile/srfi-14.c (charsets_equal): Call memcmp only if the number of
ranges is non-zero.
* libguile/stime.c (setzone): Pass 1-character buffer to
'scm_to_locale_stringbuf', instead of NULL.
* libguile/strings.c (scm_to_locale_stringbuf): Call memcpy only if the
number of bytes to copy is non-zero.
Diffstat (limited to 'libguile/bytevectors.c')
| -rw-r--r-- | libguile/bytevectors.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/libguile/bytevectors.c b/libguile/bytevectors.c index 6e3c9503d..b4dc2ea04 100644 --- a/libguile/bytevectors.c +++ b/libguile/bytevectors.c @@ -1,4 +1,4 @@ -/* Copyright 2009-2015,2018 +/* Copyright 2009-2015,2018-2019 Free Software Foundation, Inc. This file is part of Guile. @@ -671,7 +671,11 @@ SCM_DEFINE (scm_uniform_array_to_bytevector, "uniform-array->bytevector", SCM_MISC_ERROR ("uniform elements larger than 8 bits must fill whole bytes", SCM_EOL); ret = make_bytevector (byte_len, SCM_ARRAY_ELEMENT_TYPE_VU8); - memcpy (SCM_BYTEVECTOR_CONTENTS (ret), elts, byte_len); + if (byte_len != 0) + /* Empty arrays may have elements == NULL. We must avoid passing + NULL to memcpy, even if the length is zero, to avoid undefined + behavior. */ + memcpy (SCM_BYTEVECTOR_CONTENTS (ret), elts, byte_len); scm_array_handle_release (&h); |