Merge branch 'IOTSSL-628-BufferOverread'
diff --git a/ChangeLog b/ChangeLog
index 96dfb37..fed72ba 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -11,6 +11,9 @@
* Fix potential integer overflow to buffer overflow in
mbedtls_rsa_rsaes_pkcs1_v15_encrypt and mbedtls_rsa_rsaes_oaep_encrypt
(not triggerable remotely in (D)TLS).
+ * Fix a potential integer underflow to buffer overread in
+ mbedtls_rsa_rsaes_oaep_decrypt. It is not triggerable remotely in
+ SSL/TLS.
Bugfix
* Fix bug in mbedtls_mpi_add_mpi() that caused wrong results when the three
diff --git a/library/rsa.c b/library/rsa.c
index 69db220..06f96ef 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -701,6 +701,12 @@
if( md_info == NULL )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+ hlen = mbedtls_md_get_size( md_info );
+
+ // checking for integer underflow
+ if( 2 * hlen + 2 > ilen )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
/*
* RSA operation
*/
@@ -714,8 +720,6 @@
/*
* Unmask data and generate lHash
*/
- hlen = mbedtls_md_get_size( md_info );
-
mbedtls_md_init( &md_ctx );
mbedtls_md_setup( &md_ctx, md_info, 0 );