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author | Mark H Weaver <mhw@netris.org> | 2019-04-01 22:11:35 -0400 |
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committer | Mark H Weaver <mhw@netris.org> | 2019-04-16 16:54:55 -0400 |
commit | 6b1de860ab2360e8679205aecdc1c837744a4b9c (patch) | |
tree | 0357dcee473b12ca590343ad513d876eca1e8199 /libguile/srfi-14.c | |
parent | 275c96dd1fbc392e43423e91f08d2cf2fcc538a1 (diff) | |
download | guile-6b1de860ab2360e8679205aecdc1c837744a4b9c.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/srfi-14.c')
-rw-r--r-- | libguile/srfi-14.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/libguile/srfi-14.c b/libguile/srfi-14.c index af7c1d95b..a4d71e8eb 100644 --- a/libguile/srfi-14.c +++ b/libguile/srfi-14.c @@ -1,6 +1,7 @@ /* srfi-14.c --- SRFI-14 procedures for Guile * - * Copyright (C) 2001, 2004, 2006, 2007, 2009, 2011 Free Software Foundation, Inc. + * Copyright (C) 2001, 2004, 2006, 2007, 2009, 2011, + * 2019 Free Software Foundation, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License @@ -363,6 +364,12 @@ charsets_equal (scm_t_char_set *a, scm_t_char_set *b) if (a->len != b->len) return 0; + /* Empty charsets may have ranges == NULL. We must avoid passing + NULL to memcmp, even if the length is zero, to avoid undefined + behavior. */ + if (a->len == 0) + return 1; + if (memcmp (a->ranges, b->ranges, sizeof (scm_t_char_range) * a->len) != 0) return 0; |