strncpy() is deprecated [1] and as such we should use different apis to
copy string data.
We can see that ct is NUL-initialized with fc_ct_hdr_fill:
| ct = fc_ct_hdr_fill(fp, op, sizeof(struct fc_ns_rspn) + len,
...
In fc_ct_hdr_fill():
| memset(ct, 0, ct_plen);
We also calculate the length of the source string:
| len = strnlen(fc_host_symbolic_name(lport->host), 255);
then this argument is used in strncpy(), which is bad because the
pattern of (dest, src, strlen(src)) usually leaves the destination
buffer without NUL-termination. However, this seems to be correct in
this instance since fr_name is part of a seq_buf-like structure
monitoring the length:
| struct fc_ns_rspn {
| struct fc_ns_fid fr_fid; /* port ID object */
| __u8 fr_name_len;
| char fr_name[];
| } __attribute__((__packed__));
So, this is really just a byte copy into a length-bounded string. Let's
use memcpy() and mark the buffers as __nonstring.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@xxxxxxxxxxxxxxx
Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>
---
Note: build-tested only.
Found with: $ rg "strncpy\("
---
drivers/scsi/libfc/fc_encode.h | 8 ++++----
include/uapi/scsi/fc/fc_ns.h | 6 +++---
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/scsi/libfc/fc_encode.h b/drivers/scsi/libfc/fc_encode.h
index 7dcac3b6baa7..ba8cc4ee650c 100644
--- a/drivers/scsi/libfc/fc_encode.h
+++ b/drivers/scsi/libfc/fc_encode.h
@@ -140,8 +140,8 @@ static inline int fc_ct_ns_fill(struct fc_lport *lport,
ct = fc_ct_hdr_fill(fp, op, sizeof(struct fc_ns_rspn) + len,
FC_FST_DIR, FC_NS_SUBTYPE);
hton24(ct->payload.spn.fr_fid.fp_fid, lport->port_id);
- strncpy(ct->payload.spn.fr_name,
- fc_host_symbolic_name(lport->host), len);
+ memcpy(ct->payload.spn.fr_name,
+ fc_host_symbolic_name(lport->host), len);
ct->payload.spn.fr_name_len = len;
break;
@@ -150,8 +150,8 @@ static inline int fc_ct_ns_fill(struct fc_lport *lport,
ct = fc_ct_hdr_fill(fp, op, sizeof(struct fc_ns_rsnn) + len,
FC_FST_DIR, FC_NS_SUBTYPE);
put_unaligned_be64(lport->wwnn, &ct->payload.snn.fr_wwn);
- strncpy(ct->payload.snn.fr_name,
- fc_host_symbolic_name(lport->host), len);
+ memcpy(ct->payload.snn.fr_name,
+ fc_host_symbolic_name(lport->host), len);
ct->payload.snn.fr_name_len = len;
break;
diff --git a/include/uapi/scsi/fc/fc_ns.h b/include/uapi/scsi/fc/fc_ns.h
index 4cf0a40a099a..8a6f6c6b5213 100644
--- a/include/uapi/scsi/fc/fc_ns.h
+++ b/include/uapi/scsi/fc/fc_ns.h
@@ -145,7 +145,7 @@ struct fc_gid_pn_resp {
*/
struct fc_gspn_resp {
__u8 fp_name_len;
- char fp_name[];
+ char fp_name[] __nonstring;
};
/*
@@ -171,7 +171,7 @@ struct fc_ns_rn_id {
struct fc_ns_rsnn {
__be64 fr_wwn; /* node name */
__u8 fr_name_len;
- char fr_name[];
+ char fr_name[] __nonstring;
} __attribute__((__packed__));
/*
@@ -180,7 +180,7 @@ struct fc_ns_rsnn {
struct fc_ns_rspn {
struct fc_ns_fid fr_fid; /* port ID object */
__u8 fr_name_len;
- char fr_name[];
+ char fr_name[] __nonstring;
} __attribute__((__packed__));
/*
---
base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
change-id: 20231030-strncpy-drivers-scsi-libfc-fc_encode-h-5ad629f6de9c
Best regards,
--
Justin Stitt <justinstitt@xxxxxxxxxx>
