Add a test for signing content with a long ECDSA key
Due to the way the current PK API works, it may have not been clear
for the library clients, how big output buffers they should pass
to the signing functions. Depending on the key type they depend on
MPI or EC specific compile-time constants.
Inside the library, there were places, where it was assumed that
the MPI size will always be enough, even for ECDSA signatures.
However, for very small sizes of the MBEDTLS_MPI_MAX_SIZE and
sufficiently large key, the EC signature could exceed the MPI size
and cause a stack overflow.
This test establishes both conditions -- small MPI size and the use
of a long ECDSA key -- and attempts to sign an arbitrary file.
This can cause a stack overvlow if the signature buffers are not
big enough, therefore the test is performed for an ASan build.
diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index d1af18c..0aa78eb 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -786,6 +786,14 @@
$(OPENSSL) pkey -in $< -inform DER -out $@
all_final += ec_prv.pk8param.pem
+###
+### A generic SECP521R1 private key
+###
+
+secp521r1_prv.der:
+ $(OPENSSL) ecparam -genkey -name secp521r1 -noout -out secp521r1_prv.der
+all_final += secp521r1_prv.der
+
################################################################
### Generate CSRs for X.509 write test suite
################################################################
diff --git a/tests/data_files/secp521r1_prv.der b/tests/data_files/secp521r1_prv.der
new file mode 100644
index 0000000..4d342bd
--- /dev/null
+++ b/tests/data_files/secp521r1_prv.der
Binary files differ
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 369df15..b222ff5 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -611,6 +611,24 @@
#### Build and test many configurations and targets
################################################################
+component_test_large_ecdsa_key_signature () {
+
+ SMALL_MPI_MAX_SIZE=136 # Small enough to interfere with the EC signatures
+
+ msg "build: cmake + MBEDTLS_MPI_MAX_SIZE=${SMALL_MPI_MAX_SIZE}, gcc, ASan" # ~ 1 min 50s
+ scripts/config.pl set MBEDTLS_MPI_MAX_SIZE $SMALL_MPI_MAX_SIZE
+ crypto/scripts/config.pl set MBEDTLS_MPI_MAX_SIZE $SMALL_MPI_MAX_SIZE
+ CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+ make
+
+ INEVITABLY_PRESENT_FILE=Makefile
+ SIGNATURE_FILE="${INEVITABLY_PRESENT_FILE}.sig" # Warning, this is rm -f'ed below
+
+ msg "test: pk_sign secp521r1_prv.der for MBEDTLS_MPI_MAX_SIZE=${SMALL_MPI_MAX_SIZE} (ASan build)" # ~ 5s
+ if_build_succeeded programs/pkey/pk_sign tests/data_files/secp521r1_prv.der $INEVITABLY_PRESENT_FILE
+ rm -f $SIGNATURE_FILE
+}
+
component_test_default_out_of_box () {
msg "build: make, default config (out-of-box)" # ~1min
make