[PATCH] gfs2: move from strlcpy with unused retval to strscpy

[PATCH] gfs2: move from strlcpy with unused retval to strscpy

[Wolfram Sang]

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 fs/gfs2/ops_fstype.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 549879929c84..b57d9bf4b123 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -381,8 +381,8 @@ static int init_names(struct gfs2_sbd *sdp, int silent)
 	if (!table[0])
 		table = sdp->sd_vfs->s_id;
 
-	strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
-	strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
+	strscpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
+	strscpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
 
 	table = sdp->sd_table_name;
 	while ((table = strchr(table, '/')))
@@ -1439,13 +1439,13 @@ static int gfs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
 
 	switch (o) {
 	case Opt_lockproto:
-		strlcpy(args->ar_lockproto, param->string, GFS2_LOCKNAME_LEN);
+		strscpy(args->ar_lockproto, param->string, GFS2_LOCKNAME_LEN);
 		break;
 	case Opt_locktable:
-		strlcpy(args->ar_locktable, param->string, GFS2_LOCKNAME_LEN);
+		strscpy(args->ar_locktable, param->string, GFS2_LOCKNAME_LEN);
 		break;
 	case Opt_hostdata:
-		strlcpy(args->ar_hostdata, param->string, GFS2_LOCKNAME_LEN);
+		strscpy(args->ar_hostdata, param->string, GFS2_LOCKNAME_LEN);
 		break;
 	case Opt_spectator:
 		args->ar_spectator = 1;
-- 
2.35.1

Re: [Cluster-devel] [PATCH] gfs2: move from strlcpy with unused retval to strscpy

[Andrew Price]

On 18/08/2022 22:01, Wolfram Sang wrote:
> Follow the advice of the below link and prefer 'strscpy' in this
> subsystem. Conversion is 1:1 because the return value is not used.
> Generated by a coccinelle script.
> 
> Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>   fs/gfs2/ops_fstype.c | 10 +++++-----
>   1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
> index 549879929c84..b57d9bf4b123 100644
> --- a/fs/gfs2/ops_fstype.c
> +++ b/fs/gfs2/ops_fstype.c
> @@ -381,8 +381,8 @@ static int init_names(struct gfs2_sbd *sdp, int silent)
>   	if (!table[0])
>   		table = sdp->sd_vfs->s_id;
>   
> -	strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> -	strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
> +	strscpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> +	strscpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);

Perhaps the size should be changed to GFS2_LOCKNAME_LEN to match the 
size of the destination, too.

With that addition, this patch fixes this syzkaller report:

https://listman.redhat.com/archives/cluster-devel/2022-August/022755.html

Andy

>   
>   	table = sdp->sd_table_name;
>   	while ((table = strchr(table, '/')))
> @@ -1439,13 +1439,13 @@ static int gfs2_parse_param(struct fs_context *fc, struct fs_parameter *param)
>   
>   	switch (o) {
>   	case Opt_lockproto:
> -		strlcpy(args->ar_lockproto, param->string, GFS2_LOCKNAME_LEN);
> +		strscpy(args->ar_lockproto, param->string, GFS2_LOCKNAME_LEN);
>   		break;
>   	case Opt_locktable:
> -		strlcpy(args->ar_locktable, param->string, GFS2_LOCKNAME_LEN);
> +		strscpy(args->ar_locktable, param->string, GFS2_LOCKNAME_LEN);
>   		break;
>   	case Opt_hostdata:
> -		strlcpy(args->ar_hostdata, param->string, GFS2_LOCKNAME_LEN);
> +		strscpy(args->ar_hostdata, param->string, GFS2_LOCKNAME_LEN);
>   		break;
>   	case Opt_spectator:
>   		args->ar_spectator = 1;

Re: [Cluster-devel] [PATCH] gfs2: move from strlcpy with unused retval to strscpy

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 921 bytes --]

Hi Andy.

> > -	strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> > -	strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
> > +	strscpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> > +	strscpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
> 
> Perhaps the size should be changed to GFS2_LOCKNAME_LEN to match the size of
> the destination, too.
> 
> With that addition, this patch fixes this syzkaller report:
> 
> https://listman.redhat.com/archives/cluster-devel/2022-August/022755.html

Linus wrote another summary about strlcpy vs. strscpy use[1]. So, the
size argument should be the size of the smaller buffer if the buffers
are of different size. GFS2_LOCKNAME_LEN is smaller, so that looks
suitable. Shall I resend the patch with the suggested change?

All the best,

   Wolfram

[1] https://lore.kernel.org/lkml/CAHk-=wi+xbVq++uqW9YgWpHjyBHNB8a-xad+Xp23-B+eodLCEA@mail.gmail.com/


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Re: [Cluster-devel] [PATCH] gfs2: move from strlcpy with unused retval to strscpy

[Andrew Price]

On 24/08/2022 21:08, Wolfram Sang wrote:
> Hi Andy.
> 
>>> -	strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
>>> -	strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
>>> +	strscpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
>>> +	strscpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
>>
>> Perhaps the size should be changed to GFS2_LOCKNAME_LEN to match the size of
>> the destination, too.
>>
>> With that addition, this patch fixes this syzkaller report:
>>
>> https://listman.redhat.com/archives/cluster-devel/2022-August/022755.html
> 
> Linus wrote another summary about strlcpy vs. strscpy use[1]. So, the
> size argument should be the size of the smaller buffer if the buffers
> are of different size. GFS2_LOCKNAME_LEN is smaller, so that looks
> suitable. Shall I resend the patch with the suggested change?

Yes, please. I can't speak for the gfs2 maintainers but I think it would 
be a good plan, as the combination of strscpy and the size change fixes 
a bug.

Andy

> 
> All the best,
> 
>     Wolfram
> 
> [1] https://lore.kernel.org/lkml/CAHk-=wi+xbVq++uqW9YgWpHjyBHNB8a-xad+Xp23-B+eodLCEA@mail.gmail.com/
> 

Re: [Cluster-devel] [PATCH] gfs2: move from strlcpy with unused retval to strscpy

[Andreas Gruenbacher]

Wolfram and Andy,

On Thu, Aug 25, 2022 at 11:33 AM Andrew Price <anprice@redhat.com> wrote:
> On 24/08/2022 21:08, Wolfram Sang wrote:
> > Hi Andy.
> >
> >>> -   strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> >>> -   strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
> >>> +   strscpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> >>> +   strscpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
> >>
> >> Perhaps the size should be changed to GFS2_LOCKNAME_LEN to match the size of
> >> the destination, too.
> >>
> >> With that addition, this patch fixes this syzkaller report:
> >>
> >> https://listman.redhat.com/archives/cluster-devel/2022-August/022755.html
> >
> > Linus wrote another summary about strlcpy vs. strscpy use[1]. So, the
> > size argument should be the size of the smaller buffer if the buffers
> > are of different size. GFS2_LOCKNAME_LEN is smaller, so that looks
> > suitable. Shall I resend the patch with the suggested change?
>
> Yes, please. I can't speak for the gfs2 maintainers but I think it would
> be a good plan, as the combination of strscpy and the size change fixes
> a bug.

thanks, I've fixed this in for-next now:

https://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git/commit/?h=for-next&id=204c0300c4e99707e9fb6e57840aa1127060e63f

Andreas