[PATCH 32/32] esas2r: Use __mem_to_flex() with struct atto_ioctl

[Kees Cook]

As part of the work to perform bounds checking on all memcpy() uses,
replace the open-coded a deserialization of bytes out of memory into a
trailing flexible array by using a flex_array.h helper to perform the
allocation, bounds checking, and copying. This requires adding the
flexible array explicitly.

Cc: Bradley Grove <linuxdrivers at attotech.com>
Cc: "James E.J. Bottomley" <jejb at linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen at oracle.com>
Cc: linux-scsi at vger.kernel.org
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/scsi/esas2r/atioctl.h      |  1 +
 drivers/scsi/esas2r/esas2r_ioctl.c | 11 +++++++----
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/esas2r/atioctl.h b/drivers/scsi/esas2r/atioctl.h
index ff2ad9b38575..dd3437412ffc 100644
--- a/drivers/scsi/esas2r/atioctl.h
+++ b/drivers/scsi/esas2r/atioctl.h
@@ -831,6 +831,7 @@ struct __packed atto_hba_trace {
 	u32 total_length;
 	u32 trace_mask;
 	u8 reserved2[48];
+	u8 contents[];
 };
 
 #define ATTO_FUNC_SCSI_PASS_THRU     0x04
diff --git a/drivers/scsi/esas2r/esas2r_ioctl.c b/drivers/scsi/esas2r/esas2r_ioctl.c
index 08f4e43c7d9e..9310b54b1575 100644
--- a/drivers/scsi/esas2r/esas2r_ioctl.c
+++ b/drivers/scsi/esas2r/esas2r_ioctl.c
@@ -947,11 +947,14 @@ static int hba_ioctl_callback(struct esas2r_adapter *a,
 					break;
 				}
 
-				memcpy(trc + 1,
-				       a->fw_coredump_buff + offset,
-				       len);
+				if (__mem_to_flex(hi, data.trace.contents,
+						  data_length,
+						  a->fw_coredump_buff + offset,
+						  len)) {
+					hi->status = ATTO_STS_INV_FUNC;
+					break;
+				}
 
-				hi->data_length = len;
 			} else if (trc->trace_func == ATTO_TRC_TF_RESET) {
 				memset(a->fw_coredump_buff, 0,
 				       ESAS2R_FWCOREDUMP_SZ);
-- 
2.32.0