When HeaderDigest is enabled on aarch64 machines target triggers
a lot of failed crc checksum errors:
example of output in dmesg:
[ 154.495031] HeaderDigest CRC32C failed, received 0x60571c8d, computed 0x288c3ab9
[ 154.583821] Got unknown iSCSI OpCode: 0xff
[ 162.979857] HeaderDigest CRC32C failed, received 0x0712e57c, computed 0x288c3ab9
...
The problem is that the iscsit_get_rx_pdu() function uses
a stack buffer as input for the scatterlist crypto library.
This should be avoided on kernels >= 4.9 because stack buffers
may not be directly mappable to struct page when the
CONFIG_VMAP_STACK option is enabled.
This patch modifies the code so the buffer will be allocated on the heap
and adds a pointer to it in the iscsi_conn structure.
Signed-off-by: Maurizio Lombardi <mlombard@xxxxxxxxxx>
---
drivers/target/iscsi/iscsi_target.c | 4 +++-
drivers/target/iscsi/iscsi_target_login.c | 28 +++++++++++++++++++++-------
include/target/iscsi/iscsi_target_core.h | 1 +
3 files changed, 25 insertions(+), 8 deletions(-)
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 9eb10d3..a3feb9e 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -3937,10 +3937,12 @@ static bool iscsi_target_check_conn_state(struct iscsi_conn *conn)
static void iscsit_get_rx_pdu(struct iscsi_conn *conn)
{
int ret;
- u8 buffer[ISCSI_HDR_LEN], opcode;
+ u8 *buffer, opcode;
u32 checksum = 0, digest = 0;
struct kvec iov;
+ buffer = conn->conn_rx_buf;
+
while (!kthread_should_stop()) {
/*
* Ensure that both TX and RX per connection kthreads
diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index 64c5a57..11aadeb 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -129,28 +129,41 @@ int iscsi_login_setup_crypto(struct iscsi_conn *conn)
tfm = crypto_alloc_ahash("crc32c", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm)) {
pr_err("crypto_alloc_ahash() failed\n");
- return -ENOMEM;
+ goto err_exit;
+ }
+
+ conn->conn_rx_buf = kmalloc(ISCSI_HDR_LEN, GFP_KERNEL);
+ if (!conn->conn_rx_buf) {
+ pr_err("kmalloc() failed for conn_rx_buf\n");
+ goto err_free_ahash;
}
conn->conn_rx_hash = ahash_request_alloc(tfm, GFP_KERNEL);
if (!conn->conn_rx_hash) {
pr_err("ahash_request_alloc() failed for conn_rx_hash\n");
- crypto_free_ahash(tfm);
- return -ENOMEM;
+ goto err_free_rxbuf;
}
ahash_request_set_callback(conn->conn_rx_hash, 0, NULL, NULL);
conn->conn_tx_hash = ahash_request_alloc(tfm, GFP_KERNEL);
if (!conn->conn_tx_hash) {
pr_err("ahash_request_alloc() failed for conn_tx_hash\n");
- ahash_request_free(conn->conn_rx_hash);
- conn->conn_rx_hash = NULL;
- crypto_free_ahash(tfm);
- return -ENOMEM;
+ goto err_free_ahash_req;
}
ahash_request_set_callback(conn->conn_tx_hash, 0, NULL, NULL);
return 0;
+
+err_free_ahash_req:
+ ahash_request_free(conn->conn_rx_hash);
+ conn->conn_rx_hash = NULL;
+err_free_rxbuf:
+ kfree(conn->conn_rx_buf);
+ conn->conn_rx_buf = NULL;
+err_free_ahash:
+ crypto_free_ahash(tfm);
+err_exit:
+ return -ENOMEM;
}
static int iscsi_login_check_initiator_version(
@@ -1202,6 +1215,7 @@ void iscsi_target_login_sess_out(struct iscsi_conn *conn,
ahash_request_free(conn->conn_rx_hash);
crypto_free_ahash(tfm);
}
+ kfree(conn->conn_rx_buf);
free_cpumask_var(conn->conn_cpumask);
diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
index cf5f3ff..70ecbb7 100644
--- a/include/target/iscsi/iscsi_target_core.h
+++ b/include/target/iscsi/iscsi_target_core.h
@@ -584,6 +584,7 @@ struct iscsi_conn {
/* libcrypto RX and TX contexts for crc32c */
struct ahash_request *conn_rx_hash;
struct ahash_request *conn_tx_hash;
+ u8 *conn_rx_buf;
/* Used for scheduling TX and RX connection kthreads */
cpumask_var_t conn_cpumask;
unsigned int conn_rx_reset_cpumask:1;
--
Maurizio Lombardi
--
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