From: Harald Freudenberger freude@linux.ibm.com
[ Upstream commit b43088f30db1a7bff61c8486238c195c77788d6d ]
This patch fixes the warning
memcpy: detected field-spanning write (size 60) of single field "to" at drivers/s390/crypto/zcrypt_api.h:173 (size 2) WARNING: CPU: 1 PID: 2114 at drivers/s390/crypto/zcrypt_api.h:173 prep_ep11_ap_msg+0x2c6/0x2e0 [zcrypt]
The code has been rewritten to use a union in combination with a flex array to clearly state which part of the buffer the payload is to be copied in via z_copy_from_user function (which may call memcpy() in case of in-kernel calls).
Signed-off-by: Harald Freudenberger freude@linux.ibm.com Suggested-by: Jürgen Christ jchrist@linux.ibm.com Reviewed-by: Jürgen Christ jchrist@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/s390/crypto/zcrypt_msgtype6.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/s390/crypto/zcrypt_msgtype6.c b/drivers/s390/crypto/zcrypt_msgtype6.c index 8fb34b8eeb18..5ad251477593 100644 --- a/drivers/s390/crypto/zcrypt_msgtype6.c +++ b/drivers/s390/crypto/zcrypt_msgtype6.c @@ -342,7 +342,10 @@ static int xcrb_msg_to_type6cprb_msgx(bool userspace, struct ap_message *ap_msg, }; struct { struct type6_hdr hdr; - struct CPRBX cprbx; + union { + struct CPRBX cprbx; + DECLARE_FLEX_ARRAY(u8, userdata); + }; } __packed * msg = ap_msg->msg;
int rcblen = CEIL4(xcrb->request_control_blk_length); @@ -403,7 +406,8 @@ static int xcrb_msg_to_type6cprb_msgx(bool userspace, struct ap_message *ap_msg, msg->hdr.fromcardlen2 = xcrb->reply_data_length;
/* prepare CPRB */ - if (z_copy_from_user(userspace, &msg->cprbx, xcrb->request_control_blk_addr, + if (z_copy_from_user(userspace, msg->userdata, + xcrb->request_control_blk_addr, xcrb->request_control_blk_length)) return -EFAULT; if (msg->cprbx.cprb_len + sizeof(msg->hdr.function_code) > @@ -469,9 +473,14 @@ static int xcrb_msg_to_type6_ep11cprb_msgx(bool userspace, struct ap_message *ap
struct { struct type6_hdr hdr; - struct ep11_cprb cprbx; - unsigned char pld_tag; /* fixed value 0x30 */ - unsigned char pld_lenfmt; /* payload length format */ + union { + struct { + struct ep11_cprb cprbx; + unsigned char pld_tag; /* fixed value 0x30 */ + unsigned char pld_lenfmt; /* length format */ + } __packed; + DECLARE_FLEX_ARRAY(u8, userdata); + }; } __packed * msg = ap_msg->msg;
struct pld_hdr { @@ -500,7 +509,7 @@ static int xcrb_msg_to_type6_ep11cprb_msgx(bool userspace, struct ap_message *ap msg->hdr.fromcardlen1 = xcrb->resp_len;
/* Import CPRB data from the ioctl input parameter */ - if (z_copy_from_user(userspace, &msg->cprbx.cprb_len, + if (z_copy_from_user(userspace, msg->userdata, (char __force __user *)xcrb->req, xcrb->req_len)) { return -EFAULT; }