[PATCH] nfsd: fix memory leak of async_copy

[PATCH] nfsd: fix memory leak of async_copy

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

In the case where async_copy is successfully allocated but
the call to nfs4_init_cp_state fails, async_copy is not
currently freed and the memory is leaked. Fix this by kfree'ing
it before returning.

Detected by CoverityScan, CID#1471823 ("Resource leak")

Fixes: beb1814d5a8a ("NFSD create new stateid for async copy")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 fs/nfsd/nfs4proc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 8f3368353aaf..3fb96a2708b9 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1295,8 +1295,10 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
 		if (!async_copy)
 			goto out;
-		if (!nfs4_init_cp_state(nn, copy))
+		if (!nfs4_init_cp_state(nn, copy)) {
+			kfree(async_copy);
 			goto out;
+		}
 		refcount_set(&async_copy->refcount, 1);
 		memcpy(&copy->cp_res.cb_stateid, &copy->cp_stateid,
 			sizeof(copy->cp_stateid));
-- 
2.17.1

Re: [PATCH] nfsd: fix memory leak of async_copy

[Dan Carpenter]

On Mon, Jul 16, 2018 at 01:09:54PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> In the case where async_copy is successfully allocated but
> the call to nfs4_init_cp_state fails, async_copy is not
> currently freed and the memory is leaked. Fix this by kfree'ing
> it before returning.
> 
> Detected by CoverityScan, CID#1471823 ("Resource leak")
> 
> Fixes: beb1814d5a8a ("NFSD create new stateid for async copy")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  fs/nfsd/nfs4proc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 8f3368353aaf..3fb96a2708b9 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1295,8 +1295,10 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>  		async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
>  		if (!async_copy)
>  			goto out;
> -		if (!nfs4_init_cp_state(nn, copy))
> +		if (!nfs4_init_cp_state(nn, copy)) {
> +			kfree(async_copy);
>  			goto out;

It really feels like both this and the kzalloc() failure should be doing
an of fput() of copy->file_src and copy->file_dst.  The goto out_err
does an list_del(&copy->copies); but it happens before the
"list_add(&async_copy->copies ..." so that's likely wrong as well.

regards,
dan carpenter

Re: [PATCH] nfsd: fix memory leak of async_copy

[Colin Ian King]

On 17/07/18 10:30, Dan Carpenter wrote:
> On Mon, Jul 16, 2018 at 01:09:54PM +0100, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> In the case where async_copy is successfully allocated but
>> the call to nfs4_init_cp_state fails, async_copy is not
>> currently freed and the memory is leaked. Fix this by kfree'ing
>> it before returning.
>>
>> Detected by CoverityScan, CID#1471823 ("Resource leak")
>>
>> Fixes: beb1814d5a8a ("NFSD create new stateid for async copy")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>>  fs/nfsd/nfs4proc.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
>> index 8f3368353aaf..3fb96a2708b9 100644
>> --- a/fs/nfsd/nfs4proc.c
>> +++ b/fs/nfsd/nfs4proc.c
>> @@ -1295,8 +1295,10 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>>  		async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
>>  		if (!async_copy)
>>  			goto out;
>> -		if (!nfs4_init_cp_state(nn, copy))
>> +		if (!nfs4_init_cp_state(nn, copy)) {
>> +			kfree(async_copy);
>>  			goto out;
> 
> It really feels like both this and the kzalloc() failure should be doing
> an of fput() of copy->file_src and copy->file_dst.  The goto out_err
> does an list_del(&copy->copies); but it happens before the
> "list_add(&async_copy->copies ..." so that's likely wrong as well.

Good observation, thanks for spotting that. I suspect I'm a bit out of
my depth figuring out the exact error handling reaping steps here.
Perhaps this is one for the maintainers to figure out a safe cleanup on
these error paths.

> 
> regards,
> dan carpenter
> 
> --
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> 

Re: [PATCH] nfsd: fix memory leak of async_copy

[J . Bruce Fields]

Cc'ing Olga.--b.

On Tue, Jul 17, 2018 at 10:33:59AM +0100, Colin Ian King wrote:
> On 17/07/18 10:30, Dan Carpenter wrote:
> > On Mon, Jul 16, 2018 at 01:09:54PM +0100, Colin King wrote:
> >> From: Colin Ian King <colin.king@canonical.com>
> >>
> >> In the case where async_copy is successfully allocated but
> >> the call to nfs4_init_cp_state fails, async_copy is not
> >> currently freed and the memory is leaked. Fix this by kfree'ing
> >> it before returning.
> >>
> >> Detected by CoverityScan, CID#1471823 ("Resource leak")
> >>
> >> Fixes: beb1814d5a8a ("NFSD create new stateid for async copy")
> >> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> >> ---
> >>  fs/nfsd/nfs4proc.c | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> >> index 8f3368353aaf..3fb96a2708b9 100644
> >> --- a/fs/nfsd/nfs4proc.c
> >> +++ b/fs/nfsd/nfs4proc.c
> >> @@ -1295,8 +1295,10 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> >>  		async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
> >>  		if (!async_copy)
> >>  			goto out;
> >> -		if (!nfs4_init_cp_state(nn, copy))
> >> +		if (!nfs4_init_cp_state(nn, copy)) {
> >> +			kfree(async_copy);
> >>  			goto out;
> > 
> > It really feels like both this and the kzalloc() failure should be doing
> > an of fput() of copy->file_src and copy->file_dst.  The goto out_err
> > does an list_del(&copy->copies); but it happens before the
> > "list_add(&async_copy->copies ..." so that's likely wrong as well.
> 
> Good observation, thanks for spotting that. I suspect I'm a bit out of
> my depth figuring out the exact error handling reaping steps here.
> Perhaps this is one for the maintainers to figure out a safe cleanup on
> these error paths.
> 
> > 
> > regards,
> > dan carpenter
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >