Patch 1/2 fixes a potential string truncation issue in rebuild_show(). It is
intended to be minimal in order to ease potential backport.
Patch 2/2 is a bigger patch that turns some snprintf() usage in _show functions
into preferred sysfs_emit() calls.
This patch overrides the changes made in 1/2.
There is another warning when building with W=1:
1051 | "%u.%02u-%c-%02u",
| ^~~~~~~~~~~~~~~~~
drivers/scsi/myrb.c:1050:9: note: ‘snprintf’ output between 10 and 14 bytes into a destination of size 12
but I think that it is a false positive because snprintf() in Linux does not
strickly folows the standard C behavior of snprintf(). If I understand correctly
Linux handles %02u when C ignores it.
Christophe JAILLET (2):
scsi: myrb: Fix a potential string truncation in rebuild_show()
scsi: myrb: Use sysfs_emit()
drivers/scsi/myrb.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)
--
2.34.1
"physical device - not rebuilding\n" is 34 bytes long. When written in
'buf' with a limit of 32 bytes, it is truncated.
When building with W=1, it leads to:
drivers/scsi/myrb.c: In function ‘rebuild_show’:
drivers/scsi/myrb.c:1906:24: error: ‘physical device - not rebuil...’ directive output truncated writing 33 bytes into a region of size 32 [-Werror=format-truncation=]
1906 | return snprintf(buf, 32, "physical device - not rebuilding\n");
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/myrb.c:1906:24: note: ‘snprintf’ output 34 bytes into a destination of size 32
Change the allowed size to 64 to fix the issue.
Fixes: 081ff398c56c ("scsi: myrb: Add Mylex RAID controller (block interface)")
Signed-off-by: Christophe JAILLET <[email protected]>
---
drivers/scsi/myrb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/myrb.c b/drivers/scsi/myrb.c
index ca2e932dd9b7..ca2380d2d6d3 100644
--- a/drivers/scsi/myrb.c
+++ b/drivers/scsi/myrb.c
@@ -1903,15 +1903,15 @@ static ssize_t rebuild_show(struct device *dev,
unsigned char status;
if (sdev->channel < myrb_logical_channel(sdev->host))
- return snprintf(buf, 32, "physical device - not rebuilding\n");
+ return snprintf(buf, 64, "physical device - not rebuilding\n");
status = myrb_get_rbld_progress(cb, &rbld_buf);
if (rbld_buf.ldev_num != sdev->id ||
status != MYRB_STATUS_SUCCESS)
- return snprintf(buf, 32, "not rebuilding\n");
+ return snprintf(buf, 64, "not rebuilding\n");
- return snprintf(buf, 32, "rebuilding block %u of %u\n",
+ return snprintf(buf, 64, "rebuilding block %u of %u\n",
rbld_buf.ldev_size - rbld_buf.blocks_left,
rbld_buf.ldev_size);
}
--
2.34.1
In order to avoid hard-coded limits in _show() function, use the preferred
sysfs_emit() that knows better about it.
Signed-off-by: Christophe JAILLET <[email protected]>
---
drivers/scsi/myrb.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)
diff --git a/drivers/scsi/myrb.c b/drivers/scsi/myrb.c
index ca2380d2d6d3..06a5e6fb9f99 100644
--- a/drivers/scsi/myrb.c
+++ b/drivers/scsi/myrb.c
@@ -1767,7 +1767,7 @@ static ssize_t raid_state_show(struct device *dev,
int ret;
if (!sdev->hostdata)
- return snprintf(buf, 16, "Unknown\n");
+ return sysfs_emit(buf, "Unknown\n");
if (sdev->channel == myrb_logical_channel(sdev->host)) {
struct myrb_ldev_info *ldev_info = sdev->hostdata;
@@ -1775,10 +1775,10 @@ static ssize_t raid_state_show(struct device *dev,
name = myrb_devstate_name(ldev_info->state);
if (name)
- ret = snprintf(buf, 32, "%s\n", name);
+ ret = sysfs_emit(buf, "%s\n", name);
else
- ret = snprintf(buf, 32, "Invalid (%02X)\n",
- ldev_info->state);
+ ret = sysfs_emit(buf, "Invalid (%02X)\n",
+ ldev_info->state);
} else {
struct myrb_pdev_state *pdev_info = sdev->hostdata;
unsigned short status;
@@ -1796,10 +1796,10 @@ static ssize_t raid_state_show(struct device *dev,
else
name = myrb_devstate_name(pdev_info->state);
if (name)
- ret = snprintf(buf, 32, "%s\n", name);
+ ret = sysfs_emit(buf, "%s\n", name);
else
- ret = snprintf(buf, 32, "Invalid (%02X)\n",
- pdev_info->state);
+ ret = sysfs_emit(buf, "Invalid (%02X)\n",
+ pdev_info->state);
}
return ret;
}
@@ -1886,11 +1886,11 @@ static ssize_t raid_level_show(struct device *dev,
name = myrb_raidlevel_name(ldev_info->raid_level);
if (!name)
- return snprintf(buf, 32, "Invalid (%02X)\n",
- ldev_info->state);
- return snprintf(buf, 32, "%s\n", name);
+ return sysfs_emit(buf, "Invalid (%02X)\n",
+ ldev_info->state);
+ return sysfs_emit(buf, "%s\n", name);
}
- return snprintf(buf, 32, "Physical Drive\n");
+ return sysfs_emit(buf, "Physical Drive\n");
}
static DEVICE_ATTR_RO(raid_level);
@@ -1903,17 +1903,17 @@ static ssize_t rebuild_show(struct device *dev,
unsigned char status;
if (sdev->channel < myrb_logical_channel(sdev->host))
- return snprintf(buf, 64, "physical device - not rebuilding\n");
+ return sysfs_emit(buf, "physical device - not rebuilding\n");
status = myrb_get_rbld_progress(cb, &rbld_buf);
if (rbld_buf.ldev_num != sdev->id ||
status != MYRB_STATUS_SUCCESS)
- return snprintf(buf, 64, "not rebuilding\n");
+ return sysfs_emit(buf, "not rebuilding\n");
- return snprintf(buf, 64, "rebuilding block %u of %u\n",
- rbld_buf.ldev_size - rbld_buf.blocks_left,
- rbld_buf.ldev_size);
+ return sysfs_emit(buf, "rebuilding block %u of %u\n",
+ rbld_buf.ldev_size - rbld_buf.blocks_left,
+ rbld_buf.ldev_size);
}
static ssize_t rebuild_store(struct device *dev,
@@ -2140,7 +2140,7 @@ static ssize_t ctlr_num_show(struct device *dev,
struct Scsi_Host *shost = class_to_shost(dev);
struct myrb_hba *cb = shost_priv(shost);
- return snprintf(buf, 20, "%u\n", cb->ctlr_num);
+ return sysfs_emit(buf, "%u\n", cb->ctlr_num);
}
static DEVICE_ATTR_RO(ctlr_num);
@@ -2150,7 +2150,7 @@ static ssize_t firmware_show(struct device *dev,
struct Scsi_Host *shost = class_to_shost(dev);
struct myrb_hba *cb = shost_priv(shost);
- return snprintf(buf, 16, "%s\n", cb->fw_version);
+ return sysfs_emit(buf, "%s\n", cb->fw_version);
}
static DEVICE_ATTR_RO(firmware);
@@ -2160,7 +2160,7 @@ static ssize_t model_show(struct device *dev,
struct Scsi_Host *shost = class_to_shost(dev);
struct myrb_hba *cb = shost_priv(shost);
- return snprintf(buf, 16, "%s\n", cb->model_name);
+ return sysfs_emit(buf, "%s\n", cb->model_name);
}
static DEVICE_ATTR_RO(model);
--
2.34.1
On 12/12/23 10:09, Christophe JAILLET wrote:
> "physical device - not rebuilding\n" is 34 bytes long. When written in
> 'buf' with a limit of 32 bytes, it is truncated.
>
> When building with W=1, it leads to:
> drivers/scsi/myrb.c: In function ‘rebuild_show’:
> drivers/scsi/myrb.c:1906:24: error: ‘physical device - not rebuil...’ directive output truncated writing 33 bytes into a region of size 32 [-Werror=format-truncation=]
> 1906 | return snprintf(buf, 32, "physical device - not rebuilding\n");
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/myrb.c:1906:24: note: ‘snprintf’ output 34 bytes into a destination of size 32
>
> Change the allowed size to 64 to fix the issue.
>
> Fixes: 081ff398c56c ("scsi: myrb: Add Mylex RAID controller (block interface)")
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> drivers/scsi/myrb.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/myrb.c b/drivers/scsi/myrb.c
> index ca2e932dd9b7..ca2380d2d6d3 100644
> --- a/drivers/scsi/myrb.c
> +++ b/drivers/scsi/myrb.c
> @@ -1903,15 +1903,15 @@ static ssize_t rebuild_show(struct device *dev,
> unsigned char status;
>
> if (sdev->channel < myrb_logical_channel(sdev->host))
> - return snprintf(buf, 32, "physical device - not rebuilding\n");
> + return snprintf(buf, 64, "physical device - not rebuilding\n");
>
> status = myrb_get_rbld_progress(cb, &rbld_buf);
>
> if (rbld_buf.ldev_num != sdev->id ||
> status != MYRB_STATUS_SUCCESS)
> - return snprintf(buf, 32, "not rebuilding\n");
> + return snprintf(buf, 64, "not rebuilding\n");
>
> - return snprintf(buf, 32, "rebuilding block %u of %u\n",
> + return snprintf(buf, 64, "rebuilding block %u of %u\n",
> rbld_buf.ldev_size - rbld_buf.blocks_left,
> rbld_buf.ldev_size);
> }
Anyone who sees the resulting code without having seen the above patch will
wonder where the magic number '64' comes from. Please use sysfs_emit() instead
of snprintf(buf, 64, ...).
Thanks,
Bart.
Le 12/12/2023 à 21:14, Bart Van Assche a écrit :
> On 12/12/23 10:09, Christophe JAILLET wrote:
>> "physical device - not rebuilding\n" is 34 bytes long. When written in
>> 'buf' with a limit of 32 bytes, it is truncated.
>>
>> When building with W=1, it leads to:
>> drivers/scsi/myrb.c: In function ‘rebuild_show’:
>> drivers/scsi/myrb.c:1906:24: error: ‘physical device - not
>> rebuil...’ directive output truncated writing 33 bytes into a region
>> of size 32 [-Werror=format-truncation=]
>> 1906 | return snprintf(buf, 32, "physical device
>> - not rebuilding\n");
>> |
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/scsi/myrb.c:1906:24: note: ‘snprintf’ output 34 bytes into
>> a destination of size 32
>>
>> Change the allowed size to 64 to fix the issue.
>>
>> Fixes: 081ff398c56c ("scsi: myrb: Add Mylex RAID controller (block
>> interface)")
>> Signed-off-by: Christophe JAILLET <[email protected]>
>> ---
>> drivers/scsi/myrb.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/scsi/myrb.c b/drivers/scsi/myrb.c
>> index ca2e932dd9b7..ca2380d2d6d3 100644
>> --- a/drivers/scsi/myrb.c
>> +++ b/drivers/scsi/myrb.c
>> @@ -1903,15 +1903,15 @@ static ssize_t rebuild_show(struct device *dev,
>> unsigned char status;
>> if (sdev->channel < myrb_logical_channel(sdev->host))
>> - return snprintf(buf, 32, "physical device - not rebuilding\n");
>> + return snprintf(buf, 64, "physical device - not rebuilding\n");
>> status = myrb_get_rbld_progress(cb, &rbld_buf);
>> if (rbld_buf.ldev_num != sdev->id ||
>> status != MYRB_STATUS_SUCCESS)
>> - return snprintf(buf, 32, "not rebuilding\n");
>> + return snprintf(buf, 64, "not rebuilding\n");
>> - return snprintf(buf, 32, "rebuilding block %u of %u\n",
>> + return snprintf(buf, 64, "rebuilding block %u of %u\n",
>> rbld_buf.ldev_size - rbld_buf.blocks_left,
>> rbld_buf.ldev_size);
>> }
>
> Anyone who sees the resulting code without having seen the above patch will
> wonder where the magic number '64' comes from. Please use sysfs_emit()
> instead
> of snprintf(buf, 64, ...).
Ok.
In this case, do you still prefer 2 patches (one to fix rebuild_show()
and one for all the other _show function) or only 1 with everything in it?
CJ
>
> Thanks,
>
> Bart.
>
On 12/12/23 10:20, Christophe JAILLET wrote:
> In this case, do you still prefer 2 patches (one to fix
> rebuild_show() and one for all the other _show function) or only 1
> with everything in it?
One patch with all the changes is probably better.
Thanks,
Bart.