diff --git a/ChangeLog b/ChangeLog
index 4d27320..df9e1a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -23,6 +23,8 @@
      Changes were introduced in multiple places in the library.
    * Set PEM buffer to zero before freeing it, to avoid decoded private keys
      being leaked to memory after release.
+   * Fix dhm_check_range() failing to detect trivial subgroups and potentially
+     leaking 1 bit of the private key. Reported by prashantkspatil.
 
 Features
    * Allow comments in test data files.
diff --git a/library/dhm.c b/library/dhm.c
index 7076e68..668d5f7 100644
--- a/library/dhm.c
+++ b/library/dhm.c
@@ -93,6 +93,9 @@
  *
  * Parameter should be: 2 <= public_param <= P - 2
  *
+ * This means that we need to return an error if
+ *              public_param < 2 or public_param > P-2
+ *
  * For more information on the attack, see:
  *  http://www.cl.cam.ac.uk/~rja14/Papers/psandqs.pdf
  *  http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2005-2643
@@ -100,17 +103,17 @@
 static int dhm_check_range( const mbedtls_mpi *param, const mbedtls_mpi *P )
 {
     mbedtls_mpi L, U;
-    int ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA;
+    int ret = 0;
 
     mbedtls_mpi_init( &L ); mbedtls_mpi_init( &U );
 
     MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &L, 2 ) );
     MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &U, P, 2 ) );
 
-    if( mbedtls_mpi_cmp_mpi( param, &L ) >= 0 &&
-        mbedtls_mpi_cmp_mpi( param, &U ) <= 0 )
+    if( mbedtls_mpi_cmp_mpi( param, &L ) < 0 ||
+        mbedtls_mpi_cmp_mpi( param, &U ) > 0 )
     {
-        ret = 0;
+        ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA;
     }
 
 cleanup:
diff --git a/tests/suites/test_suite_dhm.data b/tests/suites/test_suite_dhm.data
index f2cdeff..e351ebd 100644
--- a/tests/suites/test_suite_dhm.data
+++ b/tests/suites/test_suite_dhm.data
@@ -1,11 +1,23 @@
 Diffie-Hellman full exchange #1
-dhm_do_dhm:10:"23":10:"5"
+dhm_do_dhm:10:"23":10:"5":0
 
 Diffie-Hellman full exchange #2
-dhm_do_dhm:10:"93450983094850938450983409623":10:"9345098304850938450983409622"
+dhm_do_dhm:10:"93450983094850938450983409623":10:"9345098304850938450983409622":0
 
 Diffie-Hellman full exchange #3
-dhm_do_dhm:10:"93450983094850938450983409623982317398171298719873918739182739712938719287391879381271":10:"9345098309485093845098340962223981329819812792137312973297123912791271"
+dhm_do_dhm:10:"93450983094850938450983409623982317398171298719873918739182739712938719287391879381271":10:"9345098309485093845098340962223981329819812792137312973297123912791271":0
+
+Diffie-Hellman trivial subgroup #1
+dhm_do_dhm:10:"23":10:"1":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
+
+Diffie-Hellman trivial subgroup #2
+dhm_do_dhm:10:"23":10:"-1":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
+
+Diffie-Hellman small modulus
+dhm_do_dhm:10:"3":10:"5":MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED
+
+Diffie-Hellman zero modulus
+dhm_do_dhm:10:"0":10:"5":MBEDTLS_ERR_DHM_BAD_INPUT_DATA
 
 Diffie-Hallman load parameters from file
 dhm_file:"data_files/dhparams.pem":"9e35f430443a09904f3a39a979797d070df53378e79c2438bef4e761f3c714553328589b041c809be1d6c6b5f1fc9f47d3a25443188253a992a56818b37ba9de5a40d362e56eff0be5417474c125c199272c8fe41dea733df6f662c92ae76556e755d10c64e6a50968f67fc6ea73d0dca8569be2ba204e23580d8bca2f4975b3":"02":128
diff --git a/tests/suites/test_suite_dhm.function b/tests/suites/test_suite_dhm.function
index b9b8e19..4fd8fff 100644
--- a/tests/suites/test_suite_dhm.function
+++ b/tests/suites/test_suite_dhm.function
@@ -9,7 +9,7 @@
 
 /* BEGIN_CASE */
 void dhm_do_dhm( int radix_P, char *input_P,
-                 int radix_G, char *input_G )
+                 int radix_G, char *input_G, int result )
 {
     mbedtls_dhm_context ctx_srv;
     mbedtls_dhm_context ctx_cli;
@@ -44,7 +44,10 @@
     /*
      * First key exchange
      */
-    TEST_ASSERT( mbedtls_dhm_make_params( &ctx_srv, x_size, ske, &ske_len, &rnd_pseudo_rand, &rnd_info ) == 0 );
+    TEST_ASSERT( mbedtls_dhm_make_params( &ctx_srv, x_size, ske, &ske_len, &rnd_pseudo_rand, &rnd_info ) == result );
+    if ( result != 0 )
+        goto exit;
+
     ske[ske_len++] = 0;
     ske[ske_len++] = 0;
     TEST_ASSERT( mbedtls_dhm_read_params( &ctx_cli, &p, ske + ske_len ) == 0 );