Commit 1f678277 authored by Nick Mathewson's avatar Nick Mathewson 🥔
Browse files

Merge remote-tracking branch 'public/bug3122_memcmp_squashed' into maint-0.2.1

parents d1c7f65a 59f9097d

changes/bug3122_memcmp

0 → 100644
+7 −0
Original line number Diff line number Diff line 
  o Security fixes

    - Replace all potentially sensitive memory comparison operations

      with versions whose runtime does not depend on the data being

      compared. This will help resist a class of attacks where an

      adversary can use variations in timing information to learn

      sensitive data.  Fix for one case of bug 3122.  (Safe memcmp

      implementation by Robert Ransom based partially on code by DJB.)

configure.in

+18 −0
Original line number Diff line number Diff line
@@ -626,6 +626,24 @@ if test "$tor_cv_twos_complement" != no ; then 
            [Define to 1 iff we represent negative integers with two's complement])

fi



# What does shifting a negative value do?

AC_CACHE_CHECK([whether right-shift on negative values does sign-extension], tor_cv_sign_extend,

[AC_RUN_IFELSE([AC_LANG_SOURCE(

[[int main () { int okay = (-60 >> 8) == -1; return okay ? 0 : 1; }]])],

       [tor_cv_sign_extend=yes],

       [tor_cv_sign_extend=no],

       [tor_cv_sign_extend=cross])])



if test "$tor_cv_sign_extend" = cross ; then

  # Cross-compiling; let's hope that the target isn't raving mad.

  AC_MSG_NOTICE([Cross-compiling: we'll assume that right-shifting negative integers causes sign-extension])

fi



if test "$tor_cv_sign_extend" != no ; then

  AC_DEFINE([RSHIFT_DOES_SIGN_EXTEND], 1,

            [Define to 1 iff right-shifting a negative value performs sign-extension])

fi



# Whether we should use the dmalloc memory allocation debugging library.

AC_MSG_CHECKING(whether to use dmalloc (debug memory allocation library))

AC_ARG_WITH(dmalloc,

src/common/Makefile.am

+2 −2
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@@ -10,7 +10,7 @@ libor_extra_source= 
endif



libor_a_SOURCES = address.c log.c util.c compat.c container.c mempool.c \

	memarea.c $(libor_extra_source)

	memarea.c di_ops.c $(libor_extra_source)

libor_crypto_a_SOURCES = crypto.c aes.c tortls.c torgzip.c



noinst_HEADERS = address.h log.h crypto.h test.h util.h compat.h aes.h torint.h tortls.h strlcpy.c strlcat.c torgzip.h container.h ht.h mempool.h memarea.h ciphers.inc
 
noinst_HEADERS = address.h log.h crypto.h test.h util.h compat.h aes.h torint.h tortls.h strlcpy.c strlcat.c torgzip.h container.h ht.h mempool.h memarea.h di_ops.h ciphers.inc

src/common/address.c

+1 −1
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@@ -830,7 +830,7 @@ tor_addr_compare_masked(const tor_addr_t *addr1, const tor_addr_t *addr2, 
        const uint8_t *a2 = tor_addr_to_in6_addr8(addr2);

        const int bytes = mbits >> 3;

        const int leftover_bits = mbits & 7;

        if (bytes && (r = memcmp(a1, a2, bytes))) {

        if (bytes && (r = tor_memcmp(a1, a2, bytes))) {

          return r;

        } else if (leftover_bits) {

          uint8_t b1 = a1[bytes] >> (8-leftover_bits);

src/common/compat.c

+3 −1
Original line number Diff line number Diff line
@@ -312,6 +312,8 @@ tor_vsnprintf(char *str, size_t size, const char *format, va_list args) 
 * <b>needle</b>, return a pointer to the first occurrence of the needle

 * within the haystack, or NULL if there is no such occurrence.

 *

 * This function is <em>not</em> timing-safe.

 *

 * Requires that nlen be greater than zero.

 */

const void *
@@ -336,7 +338,7 @@ tor_memmem(const void *_haystack, size_t hlen, 
  while ((p = memchr(p, first, end-p))) {

    if (p+nlen > end)

      return NULL;

    if (!memcmp(p, needle, nlen))

    if (fast_memeq(p, needle, nlen))

      return p;

    ++p;

  }