diff options
| -rw-r--r-- | src/include/k5-platform.h | 8 | ||||
| -rw-r--r-- | src/util/support/Makefile.in | 5 | ||||
| -rw-r--r-- | src/util/support/bcmp.c | 44 | ||||
| -rw-r--r-- | src/util/support/libkrb5support-fixed.exports | 1 |
4 files changed, 57 insertions, 1 deletions
diff --git a/src/include/k5-platform.h b/src/include/k5-platform.h index ad7888ab1..7203a994a 100644 --- a/src/include/k5-platform.h +++ b/src/include/k5-platform.h @@ -40,6 +40,7 @@ * + [v]asprintf * + mkstemp * + zap (support function; macro is in k5-int.h) + * + constant time memory comparison * + path manipulation * + _, N_, dgettext, bindtextdomain (for localization) */ @@ -1049,6 +1050,13 @@ extern int krb5int_gettimeofday(struct timeval *tp, void *ignore); extern void krb5int_zap(void *ptr, size_t len); /* + * Return 0 if the n-byte memory regions p1 and p2 are equal, and nonzero if + * they are not. The function is intended to take the same amount of time + * regardless of how many bytes of p1 and p2 are equal. + */ +int k5_bcmp(const void *p1, const void *p2, size_t n); + +/* * Split a path into parent directory and basename. Either output parameter * may be NULL if the caller doesn't need it. parent_out will be empty if path * has no basename. basename_out will be empty if path ends with a path diff --git a/src/util/support/Makefile.in b/src/util/support/Makefile.in index 01be06d21..979b4cd3e 100644 --- a/src/util/support/Makefile.in +++ b/src/util/support/Makefile.in @@ -71,6 +71,7 @@ STLIBOBJS= \ path.o \ base64.o \ json.o \ + bcmp.o \ $(GETTIMEOFDAY_ST_OBJ) \ $(IPC_ST_OBJ) \ $(STRLCPY_ST_OBJ) \ @@ -92,6 +93,7 @@ LIBOBJS= \ $(OUTPRE)path.$(OBJEXT) \ $(OUTPRE)base64.$(OBJEXT) \ $(OUTPRE)json.$(OBJEXT) \ + $(OUTPRE)bcmp.$(OBJEXT) \ $(GETTIMEOFDAY_OBJ) \ $(IPC_OBJ) \ $(STRLCPY_OBJ) \ @@ -121,7 +123,8 @@ SRCS=\ $(srcdir)/zap.c \ $(srcdir)/path.c \ $(srcdir)/base64.c \ - $(srcdir)/json.c + $(srcdir)/json.c \ + $(srcdir)/bcmp.c SHLIB_EXPDEPS = # Add -lm if dumping thread stats, for sqrt. diff --git a/src/util/support/bcmp.c b/src/util/support/bcmp.c new file mode 100644 index 000000000..71728a687 --- /dev/null +++ b/src/util/support/bcmp.c @@ -0,0 +1,44 @@ +/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */ +/* util/support/bitcmp.c - Constant-time byte comparison function */ +/* + * Copyright (C) 2013 by the Massachusetts Institute of Technology. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "k5-platform.h" + +int +k5_bcmp(const void *p1, const void *p2, size_t n) +{ + const unsigned char *c1 = p1, *c2 = p2; + unsigned char x = 0; + + for (; n > 0; c1++, c2++, n--) + x |= *c1 ^ *c2; + return x; +} diff --git a/src/util/support/libkrb5support-fixed.exports b/src/util/support/libkrb5support-fixed.exports index 876f360e4..2f38242d9 100644 --- a/src/util/support/libkrb5support-fixed.exports +++ b/src/util/support/libkrb5support-fixed.exports @@ -1,5 +1,6 @@ k5_base64_decode k5_base64_encode +k5_bcmp k5_buf_init_fixed k5_buf_init_dynamic k5_buf_add |