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ced1775490
emulate strlcat and strlcpy, which support size-bounded string copying and concatenation for improved security. * libltdl/Makefile.am: Optionally build source files libltdl/lt__strl.c and libltdl/libltdl/lt__strl.h. * m4/ltdl.m4 (LTDL_INIT): Add checks for strlcat and strlcpy.
127 lines
3.4 KiB
C
127 lines
3.4 KiB
C
/* lt__strl.c -- size-bounded string copying and concatenation
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Copyright (C) 2004 Free Software Foundation, Inc.
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Written by Bob Friesenhahn <bfriesen@simple.dallas.tx.us>
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NOTE: The canonical source of this file is maintained with the
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GNU Libtool package. Report bugs to bug-libtool@gnu.org.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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As a special exception to the GNU Lesser General Public License,
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if you distribute this file as part of a program or library that
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is built using GNU libtool, you may include it under the same
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distribution terms that you use for the rest of that program.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA
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*/
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#include <assert.h>
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#include <string.h>
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#include "lt__strl.h"
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/*
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lt_strlcat appends the NULL-terminated string src to the end of dst.
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It will append at most dstsize - strlen(dst) - 1 bytes,
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NULL-terminating the result. The total length of the string which
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would have been created given sufficient buffer size (may be longer
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than dstsize) is returned. This function substitutes for strlcat()
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which is available under NetBSD, FreeBSD and Solaris 9.
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Buffer overflow can be checked as follows:
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if (lt_strlcat(dst, src, dstsize) >= dstsize)
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return -1;
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*/
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#if !defined(HAVE_STRLCAT)
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size_t
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lt_strlcat(char *dst, const char *src, const size_t dstsize)
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{
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size_t length;
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char *p;
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const char *q;
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assert(dst != NULL);
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assert(src != (const char *) NULL);
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assert(dstsize >= 1);
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length=strlen(dst);
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/*
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Copy remaining characters from src while constraining length to
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size - 1.
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*/
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for ( p = dst + length, q = src;
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(*q != 0) && (length < dstsize - 1) ;
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length++, p++, q++ )
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*p = *q;
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dst[length]='\0';
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/*
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Add remaining length of src to length.
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*/
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while (*q++)
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length++;
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return length;
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}
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#endif /* !defined(HAVE_STRLCAT) */
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/*
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lt_strlcpy copies up to dstsize - 1 characters from the NULL-terminated
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string src to dst, NULL-terminating the result. The total length of
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the string which would have been created given sufficient buffer
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size (may be longer than dstsize) is returned. This function
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substitutes for strlcpy() which is available under OpenBSD, FreeBSD
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and Solaris 9.
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Buffer overflow can be checked as follows:
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if (lt_strlcpy(dst, src, dstsize) >= dstsize)
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return -1;
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*/
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#if !defined(HAVE_STRLCPY)
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size_t
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lt_strlcpy(char *dst, const char *src, const size_t dstsize)
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{
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size_t length=0;
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char *p;
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const char *q;
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assert(dst != NULL);
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assert(src != (const char *) NULL);
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assert(dstsize >= 1);
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/*
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Copy src to dst within bounds of size-1.
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*/
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for ( p=dst, q=src, length=0 ;
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(*q != 0) && (length < dstsize-1) ;
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length++, p++, q++ )
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*p = *q;
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dst[length]='\0';
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/*
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Add remaining length of src to length.
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*/
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while (*q++)
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length++;
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return length;
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}
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#endif /* !defined(HAVE_STRLCPY) */
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