summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--gtests/freebl_gtest/mpi_unittest.cc82
-rw-r--r--lib/freebl/mpi/mpi.c61
-rw-r--r--lib/freebl/mpi/mpi.h3
3 files changed, 122 insertions, 24 deletions
diff --git a/gtests/freebl_gtest/mpi_unittest.cc b/gtests/freebl_gtest/mpi_unittest.cc
index 4fed1a40e..2ccb8c351 100644
--- a/gtests/freebl_gtest/mpi_unittest.cc
+++ b/gtests/freebl_gtest/mpi_unittest.cc
@@ -15,7 +15,7 @@
#include "mpi.h"
namespace nss_test {
-void gettime(struct timespec *tp) {
+void gettime(struct timespec* tp) {
#ifdef __MACH__
clock_serv_t cclock;
mach_timespec_t mts;
@@ -69,6 +69,39 @@ class MPITest : public ::testing::Test {
mp_clear(&b);
mp_clear(&c);
}
+
+ void dump(const std::string& prefix, const uint8_t* buf, size_t len) {
+ auto flags = std::cerr.flags();
+ std::cerr << prefix << ": [" << std::dec << len << "] ";
+ for (size_t i = 0; i < len; ++i) {
+ std::cerr << std::hex << std::setw(2) << std::setfill('0')
+ << static_cast<int>(buf[i]);
+ }
+ std::cerr << std::endl << std::resetiosflags(flags);
+ }
+
+ void TestToFixedOctets(const std::vector<uint8_t>& ref, size_t len) {
+ mp_int a;
+ ASSERT_EQ(MP_OKAY, mp_init(&a));
+ ASSERT_EQ(MP_OKAY, mp_read_unsigned_octets(&a, ref.data(), ref.size()));
+ uint8_t buf[len];
+ ASSERT_EQ(MP_OKAY, mp_to_fixlen_octets(&a, buf, len));
+ size_t compare;
+ if (len > ref.size()) {
+ for (size_t i = 0; i < len - ref.size(); ++i) {
+ ASSERT_EQ(0U, buf[i]) << "index " << i << " should be zero";
+ }
+ compare = ref.size();
+ } else {
+ compare = len;
+ }
+ dump("value", ref.data(), ref.size());
+ dump("output", buf, len);
+ ASSERT_EQ(0, memcmp(buf + len - compare, ref.data() + ref.size() - compare,
+ compare))
+ << "comparing " << compare << " octets";
+ mp_clear(&a);
+ }
};
TEST_F(MPITest, MpiCmp01Test) { TestCmp("0", "1", -1); }
@@ -113,6 +146,47 @@ TEST_F(MPITest, MpiCmpUnalignedTest) {
}
#endif
+TEST_F(MPITest, MpiFixlenOctetsZero) {
+ std::vector<uint8_t> zero = {0};
+ TestToFixedOctets(zero, 1);
+ TestToFixedOctets(zero, 2);
+ TestToFixedOctets(zero, sizeof(mp_digit));
+ TestToFixedOctets(zero, sizeof(mp_digit) + 1);
+}
+
+TEST_F(MPITest, MpiFixlenOctetsVarlen) {
+ std::vector<uint8_t> packed;
+ for (size_t i = 0; i < sizeof(mp_digit) * 2; ++i) {
+ packed.push_back(0xa4); // Any non-zero value will do.
+ TestToFixedOctets(packed, packed.size());
+ TestToFixedOctets(packed, packed.size() + 1);
+ TestToFixedOctets(packed, packed.size() + sizeof(mp_digit));
+ }
+}
+
+TEST_F(MPITest, MpiFixlenOctetsTooSmall) {
+ uint8_t buf[sizeof(mp_digit) * 3];
+ std::vector<uint8_t> ref;
+ for (size_t i = 0; i < sizeof(mp_digit) * 2; i++) {
+ ref.push_back(3); // Any non-zero value will do.
+ dump("ref", ref.data(), ref.size());
+
+ mp_int a;
+ ASSERT_EQ(MP_OKAY, mp_init(&a));
+ ASSERT_EQ(MP_OKAY, mp_read_unsigned_octets(&a, ref.data(), ref.size()));
+#ifdef DEBUG
+ // ARGCHK maps to assert() in a debug build.
+ EXPECT_DEATH(mp_to_fixlen_octets(&a, buf, ref.size() - 1), "");
+#else
+ EXPECT_EQ(MP_BADARG, mp_to_fixlen_octets(&a, buf, ref.size() - 1));
+#endif
+ ASSERT_EQ(MP_OKAY, mp_to_fixlen_octets(&a, buf, ref.size()));
+ ASSERT_EQ(0, memcmp(buf, ref.data(), ref.size()));
+
+ mp_clear(&a);
+ }
+}
+
// This test is slow. Disable it by default so we can run these tests on CI.
class DISABLED_MPITest : public ::testing::Test {};
@@ -127,17 +201,17 @@ TEST_F(DISABLED_MPITest, MpiCmpConstTest) {
mp_read_radix(
&a,
- const_cast<char *>(
+ const_cast<char*>(
"FFFFFFFF00000000FFFFFFFFFFFFFFFFBCE6FAADA7179E84F3B9CAC2FC632551"),
16);
mp_read_radix(
&b,
- const_cast<char *>(
+ const_cast<char*>(
"FF0FFFFF00000000FFFFFFFFFFFFFFFFBCE6FAADA7179E84F3B9CAC2FC632551"),
16);
mp_read_radix(
&c,
- const_cast<char *>(
+ const_cast<char*>(
"FFFFFFFF00000000FFFFFFFFFFFFFFFFBCE6FAADA7179E84F3B9CAC2FC632550"),
16);
diff --git a/lib/freebl/mpi/mpi.c b/lib/freebl/mpi/mpi.c
index 8c893fb5f..401eac51d 100644
--- a/lib/freebl/mpi/mpi.c
+++ b/lib/freebl/mpi/mpi.c
@@ -4775,38 +4775,61 @@ mp_to_signed_octets(const mp_int *mp, unsigned char *str, mp_size maxlen)
/* }}} */
/* {{{ mp_to_fixlen_octets(mp, str) */
-/* output a buffer of big endian octets exactly as long as requested. */
+/* output a buffer of big endian octets exactly as long as requested.
+ constant time on the value of mp. */
mp_err
mp_to_fixlen_octets(const mp_int *mp, unsigned char *str, mp_size length)
{
- int ix, pos = 0;
+ int ix, jx;
unsigned int bytes;
- ARGCHK(mp != NULL && str != NULL && !SIGN(mp), MP_BADARG);
-
- bytes = mp_unsigned_octet_size(mp);
- ARGCHK(bytes <= length, MP_BADARG);
+ ARGCHK(mp != NULL, MP_BADARG);
+ ARGCHK(str != NULL, MP_BADARG);
+ ARGCHK(!SIGN(mp), MP_BADARG);
+ ARGCHK(length > 0, MP_BADARG);
+
+ /* Constant time on the value of mp. Don't use mp_unsigned_octet_size. */
+ bytes = USED(mp) * MP_DIGIT_SIZE;
+
+ /* If the output is shorter than the native size of mp, then check that any
+ * bytes not written have zero values. This check isn't constant time on
+ * the assumption that timing-sensitive callers can guarantee that mp fits
+ * in the allocated space. */
+ ix = USED(mp) - 1;
+ if (bytes > length) {
+ unsigned int zeros = bytes - length;
+
+ while (zeros >= MP_DIGIT_SIZE) {
+ ARGCHK(DIGIT(mp, ix) == 0, MP_BADARG);
+ zeros -= MP_DIGIT_SIZE;
+ ix--;
+ }
- /* place any needed leading zeros */
- for (; length > bytes; --length) {
- *str++ = 0;
+ if (zeros > 0) {
+ mp_digit d = DIGIT(mp, ix);
+ mp_digit m = ~0ULL << ((MP_DIGIT_SIZE - zeros) * CHAR_BIT);
+ ARGCHK((d & m) == 0, MP_BADARG);
+ for (jx = MP_DIGIT_SIZE - zeros - 1; jx >= 0; jx--) {
+ *str++ = d >> (jx * CHAR_BIT);
+ }
+ ix--;
+ }
+ } else if (bytes < length) {
+ /* Place any needed leading zeros. */
+ unsigned int zeros = length - bytes;
+ memset(str, 0, zeros);
+ str += zeros;
}
- /* Iterate over each digit... */
- for (ix = USED(mp) - 1; ix >= 0; ix--) {
+ /* Iterate over each whole digit... */
+ for (; ix >= 0; ix--) {
mp_digit d = DIGIT(mp, ix);
- int jx;
/* Unpack digit bytes, high order first */
- for (jx = sizeof(mp_digit) - 1; jx >= 0; jx--) {
- unsigned char x = (unsigned char)(d >> (jx * CHAR_BIT));
- if (!pos && !x) /* suppress leading zeros */
- continue;
- str[pos++] = x;
+ for (jx = MP_DIGIT_SIZE - 1; jx >= 0; jx--) {
+ *str++ = d >> (jx * CHAR_BIT);
}
}
- if (!pos)
- str[pos++] = 0;
return MP_OKAY;
} /* end mp_to_fixlen_octets() */
/* }}} */
diff --git a/lib/freebl/mpi/mpi.h b/lib/freebl/mpi/mpi.h
index 97af0f069..d5aef46d7 100644
--- a/lib/freebl/mpi/mpi.h
+++ b/lib/freebl/mpi/mpi.h
@@ -128,7 +128,8 @@ typedef int mp_sword;
#define MP_WORD_MAX UINT_MAX
#endif
-#define MP_DIGIT_BIT (CHAR_BIT * sizeof(mp_digit))
+#define MP_DIGIT_SIZE sizeof(mp_digit)
+#define MP_DIGIT_BIT (CHAR_BIT * MP_DIGIT_SIZE)
#define MP_WORD_BIT (CHAR_BIT * sizeof(mp_word))
#define MP_RADIX (1 + (mp_word)MP_DIGIT_MAX)
View Lorry Controller Status