libtuee: allow NULL output coefficients in TEE_BigIntComputeExtendedG…

…cd() Fix TEE_BigIntComputeExtendedGcd() for when only one of u and v output coefficients reference is NULL as allowed by the GP TEE Internal Core API specification. Reported-by: Stefan Schmidt <[email protected]> Closes: OP-TEE#7217 Signed-off-by: Etienne Carriere <[email protected]> Reviewed-by: Jerome Forissier <[email protected]> Reviewed-by: Jens Wiklander <[email protected]>
gagachang · Jan 13, 2025 · 703ebb7 · 703ebb7
1 parent defc9e0
commit 703ebb7
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/lib/libutee/tee_api_arith_mpi.c b/lib/libutee/tee_api_arith_mpi.c
@@ -864,8 +864,10 @@ void TEE_BigIntComputeExtendedGcd(TEE_BigInt *gcd, TEE_BigInt *u,
 		mpi_u.s *= s1;
 		mpi_v.s *= s2;
 
-		MPI_CHECK(copy_mpi_to_bigint(&mpi_u, u));
-		MPI_CHECK(copy_mpi_to_bigint(&mpi_v, v));
+		if (u)
+			MPI_CHECK(copy_mpi_to_bigint(&mpi_u, u));
+		if (v)
+			MPI_CHECK(copy_mpi_to_bigint(&mpi_v, v));
 		mbedtls_mpi_free(&mpi_u);
 		mbedtls_mpi_free(&mpi_v);
 	}