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authorArnd Bergmann <arnd@arndb.de>2020-10-26 17:06:13 +0100
committerMartin K. Petersen <martin.petersen@oracle.com>2020-10-29 21:49:25 -0400
commit8fd9efca86d083bb6fe8676ed4edd1c626d19367 (patch)
treef8e44be302d811cbee19a959a5ac6bc703f82759 /drivers/scsi/libfc
parente31ac898ac298b7a0451b0406769a024bd286e4d (diff)
scsi: libfc: Work around -Warray-bounds warning
Building libfc with gcc -Warray-bounds identifies a number of cases in one file where a strncpy() is performed into a single-byte character array: In file included from include/linux/bitmap.h:9, from include/linux/cpumask.h:12, from include/linux/smp.h:13, from include/linux/lockdep.h:14, from include/linux/spinlock.h:59, from include/linux/debugobjects.h:6, from include/linux/timer.h:8, from include/scsi/libfc.h:11, from drivers/scsi/libfc/fc_elsct.c:17: In function 'strncpy', inlined from 'fc_ct_ms_fill.constprop' at drivers/scsi/libfc/fc_encode.h:235:3: include/linux/string.h:290:30: warning: '__builtin_strncpy' offset [56, 135] from the object at 'pp' is out of the bounds of referenced subobject 'value' with type '__u8[1]' {aka 'unsigned char[1]'} at offset 56 [-Warray-bounds] 290 | #define __underlying_strncpy __builtin_strncpy | ^ include/linux/string.h:300:9: note: in expansion of macro '__underlying_strncpy' 300 | return __underlying_strncpy(p, q, size); | ^~~~~~~~~~~~~~~~~~~~ This is not a bug because the 1-byte array is used as an odd way to express a variable-length data field here. I tried to convert it to a flexible-array member, but in the end could not figure out why the sizeof(struct fc_fdmi_???) are used the way they are, and how to properly convert those. Work around this instead by abstracting the string copy in a slightly higher-level function fc_ct_hdr_fill() helper that strscpy() and memset() to achieve the same result as strncpy() but does not require a zero-terminated input and does not get checked for the array overflow because gcc (so far) does not understand the behavior of strscpy(). Link: https://lore.kernel.org/r/20201026160705.3706396-2-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/libfc')
-rw-r--r--drivers/scsi/libfc/fc_encode.h30
1 files changed, 19 insertions, 11 deletions
diff --git a/drivers/scsi/libfc/fc_encode.h b/drivers/scsi/libfc/fc_encode.h
index 18203cae04b2..602c97a651bc 100644
--- a/drivers/scsi/libfc/fc_encode.h
+++ b/drivers/scsi/libfc/fc_encode.h
@@ -163,6 +163,14 @@ static inline int fc_ct_ns_fill(struct fc_lport *lport,
return 0;
}
+static inline void fc_ct_ms_fill_attr(struct fc_fdmi_attr_entry *entry,
+ const char *in, size_t len)
+{
+ int copied = strscpy(entry->value, in, len);
+ if (copied > 0)
+ memset(entry->value, copied, len - copied);
+}
+
/**
* fc_ct_ms_fill() - Fill in a mgmt service request frame
* @lport: local port.
@@ -232,7 +240,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
put_unaligned_be16(FC_FDMI_HBA_ATTR_MANUFACTURER,
&entry->type);
put_unaligned_be16(len, &entry->len);
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_manufacturer(lport->host),
FC_FDMI_HBA_ATTR_MANUFACTURER_LEN);
@@ -244,7 +252,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
put_unaligned_be16(FC_FDMI_HBA_ATTR_SERIALNUMBER,
&entry->type);
put_unaligned_be16(len, &entry->len);
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_serial_number(lport->host),
FC_FDMI_HBA_ATTR_SERIALNUMBER_LEN);
@@ -256,7 +264,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
put_unaligned_be16(FC_FDMI_HBA_ATTR_MODEL,
&entry->type);
put_unaligned_be16(len, &entry->len);
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_model(lport->host),
FC_FDMI_HBA_ATTR_MODEL_LEN);
@@ -268,7 +276,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
put_unaligned_be16(FC_FDMI_HBA_ATTR_MODELDESCRIPTION,
&entry->type);
put_unaligned_be16(len, &entry->len);
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_model_description(lport->host),
FC_FDMI_HBA_ATTR_MODELDESCR_LEN);
@@ -280,7 +288,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
put_unaligned_be16(FC_FDMI_HBA_ATTR_HARDWAREVERSION,
&entry->type);
put_unaligned_be16(len, &entry->len);
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_hardware_version(lport->host),
FC_FDMI_HBA_ATTR_HARDWAREVERSION_LEN);
@@ -292,7 +300,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
put_unaligned_be16(FC_FDMI_HBA_ATTR_DRIVERVERSION,
&entry->type);
put_unaligned_be16(len, &entry->len);
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_driver_version(lport->host),
FC_FDMI_HBA_ATTR_DRIVERVERSION_LEN);
@@ -304,7 +312,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
put_unaligned_be16(FC_FDMI_HBA_ATTR_OPTIONROMVERSION,
&entry->type);
put_unaligned_be16(len, &entry->len);
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_optionrom_version(lport->host),
FC_FDMI_HBA_ATTR_OPTIONROMVERSION_LEN);
@@ -316,7 +324,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
put_unaligned_be16(FC_FDMI_HBA_ATTR_FIRMWAREVERSION,
&entry->type);
put_unaligned_be16(len, &entry->len);
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_firmware_version(lport->host),
FC_FDMI_HBA_ATTR_FIRMWAREVERSION_LEN);
@@ -411,7 +419,7 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
&entry->type);
put_unaligned_be16(len, &entry->len);
/* Use the sysfs device name */
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
dev_name(&lport->host->shost_gendev),
strnlen(dev_name(&lport->host->shost_gendev),
FC_FDMI_PORT_ATTR_HOSTNAME_LEN));
@@ -425,12 +433,12 @@ static inline int fc_ct_ms_fill(struct fc_lport *lport,
&entry->type);
put_unaligned_be16(len, &entry->len);
if (strlen(fc_host_system_hostname(lport->host)))
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
fc_host_system_hostname(lport->host),
strnlen(fc_host_system_hostname(lport->host),
FC_FDMI_PORT_ATTR_HOSTNAME_LEN));
else
- strncpy((char *)&entry->value,
+ fc_ct_ms_fill_attr(entry,
init_utsname()->nodename,
FC_FDMI_PORT_ATTR_HOSTNAME_LEN);
break;