From: Colin Ian King <[email protected]>
There are two error return paths where the call to path_put is
dereferencing the null pointer 'stack'. Fix this by avoiding the
error exit path via label 'out_err' that will lead to the path_put
calls and instead just return the error code directly.
Addresses-Coverity: ("Dereference after null check)"
Fixes: 4155c10a0309 ("ovl: clean up getting lower layers")
Signed-off-by: Colin Ian King <[email protected]>
---
fs/overlayfs/super.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 1094836f7e31..4be1b041b32c 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1594,20 +1594,18 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
unsigned int i;
struct ovl_entry *oe;
- err = -EINVAL;
if (!ofs->config.upperdir && numlower == 1) {
pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n");
- goto out_err;
+ return ERR_PTR(-EINVAL);
} else if (!ofs->config.upperdir && ofs->config.nfs_export &&
ofs->config.redirect_follow) {
pr_warn("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
ofs->config.nfs_export = false;
}
- err = -ENOMEM;
stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL);
if (!stack)
- goto out_err;
+ return ERR_PTR(-ENOMEM);
err = -EINVAL;
for (i = 0; i < numlower; i++) {
--
2.25.1
On Wed, Jun 3, 2020 at 6:46 PM Colin King <[email protected]> wrote:
>
> From: Colin Ian King <[email protected]>
>
> There are two error return paths where the call to path_put is
> dereferencing the null pointer 'stack'. Fix this by avoiding the
> error exit path via label 'out_err' that will lead to the path_put
> calls and instead just return the error code directly.
>
> Addresses-Coverity: ("Dereference after null check)"
> Fixes: 4155c10a0309 ("ovl: clean up getting lower layers")
> Signed-off-by: Colin Ian King <[email protected]>
Which branch is that based on?
Doesn't seem to apply to master nor next
> ---
> fs/overlayfs/super.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 1094836f7e31..4be1b041b32c 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -1594,20 +1594,18 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
> unsigned int i;
> struct ovl_entry *oe;
>
> - err = -EINVAL;
> if (!ofs->config.upperdir && numlower == 1) {
> pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n");
> - goto out_err;
> + return ERR_PTR(-EINVAL);
> } else if (!ofs->config.upperdir && ofs->config.nfs_export &&
> ofs->config.redirect_follow) {
> pr_warn("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
> ofs->config.nfs_export = false;
> }
>
> - err = -ENOMEM;
> stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL);
> if (!stack)
> - goto out_err;
> + return ERR_PTR(-ENOMEM);
>
> err = -EINVAL;
> for (i = 0; i < numlower; i++) {
> --
> 2.25.1
>
On Wed, Jun 3, 2020 at 7:15 PM Colin Ian King <[email protected]> wrote:
>
> On 03/06/2020 17:11, Amir Goldstein wrote:
> > On Wed, Jun 3, 2020 at 6:46 PM Colin King <[email protected]> wrote:
> >>
> >> From: Colin Ian King <[email protected]>
> >>
> >> There are two error return paths where the call to path_put is
> >> dereferencing the null pointer 'stack'. Fix this by avoiding the
> >> error exit path via label 'out_err' that will lead to the path_put
> >> calls and instead just return the error code directly.
> >>
> >> Addresses-Coverity: ("Dereference after null check)"
> >> Fixes: 4155c10a0309 ("ovl: clean up getting lower layers")
> >> Signed-off-by: Colin Ian King <[email protected]>
> >
> >
> > Which branch is that based on?
> > Doesn't seem to apply to master nor next
>
> It was based on today's linux-next
Oh, I'm behind.
Sorry for the noise.
Thanks,
Amir.
On 03/06/2020 17:11, Amir Goldstein wrote:
> On Wed, Jun 3, 2020 at 6:46 PM Colin King <[email protected]> wrote:
>>
>> From: Colin Ian King <[email protected]>
>>
>> There are two error return paths where the call to path_put is
>> dereferencing the null pointer 'stack'. Fix this by avoiding the
>> error exit path via label 'out_err' that will lead to the path_put
>> calls and instead just return the error code directly.
>>
>> Addresses-Coverity: ("Dereference after null check)"
>> Fixes: 4155c10a0309 ("ovl: clean up getting lower layers")
>> Signed-off-by: Colin Ian King <[email protected]>
>
>
> Which branch is that based on?
> Doesn't seem to apply to master nor next
It was based on today's linux-next
>
>> ---
>> fs/overlayfs/super.c | 6 ++----
>> 1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
>> index 1094836f7e31..4be1b041b32c 100644
>> --- a/fs/overlayfs/super.c
>> +++ b/fs/overlayfs/super.c
>> @@ -1594,20 +1594,18 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
>> unsigned int i;
>> struct ovl_entry *oe;
>>
>> - err = -EINVAL;
>> if (!ofs->config.upperdir && numlower == 1) {
>> pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n");
>> - goto out_err;
>> + return ERR_PTR(-EINVAL);
>> } else if (!ofs->config.upperdir && ofs->config.nfs_export &&
>> ofs->config.redirect_follow) {
>> pr_warn("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
>> ofs->config.nfs_export = false;
>> }
>>
>> - err = -ENOMEM;
>> stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL);
>> if (!stack)
>> - goto out_err;
>> + return ERR_PTR(-ENOMEM);
>>
>> err = -EINVAL;
>> for (i = 0; i < numlower; i++) {
>> --
>> 2.25.1
>>
On Wed, Jun 3, 2020 at 6:15 PM Colin Ian King <[email protected]> wrote:
>
> On 03/06/2020 17:11, Amir Goldstein wrote:
> > On Wed, Jun 3, 2020 at 6:46 PM Colin King <[email protected]> wrote:
> >>
> >> From: Colin Ian King <[email protected]>
> >>
> >> There are two error return paths where the call to path_put is
> >> dereferencing the null pointer 'stack'. Fix this by avoiding the
> >> error exit path via label 'out_err' that will lead to the path_put
> >> calls and instead just return the error code directly.
> >>
> >> Addresses-Coverity: ("Dereference after null check)"
> >> Fixes: 4155c10a0309 ("ovl: clean up getting lower layers")
> >> Signed-off-by: Colin Ian King <[email protected]>
> >
> >
> > Which branch is that based on?
> > Doesn't seem to apply to master nor next
>
> It was based on today's linux-next
Yeah, it's actually
Fixes: 73819e26c0f0 ("ovl: get rid of redundant members in struct ovl_fs")
So I'll just fold your patch. There's still a change in the loop
count for later errors, but that's okay, since
ovl_lower_dir()/ovl_mount_dir_noesc() use the path_put_init() variant.
Actually ovl_lower_dir() can get rid of that path_put_init()
completely, since now the only caller will take care of that...
Thanks for reporting!
Miklos
On 04/06/2020 08:25, Miklos Szeredi wrote:
> On Wed, Jun 3, 2020 at 6:15 PM Colin Ian King <[email protected]> wrote:
>>
>> On 03/06/2020 17:11, Amir Goldstein wrote:
>>> On Wed, Jun 3, 2020 at 6:46 PM Colin King <[email protected]> wrote:
>>>>
>>>> From: Colin Ian King <[email protected]>
>>>>
>>>> There are two error return paths where the call to path_put is
>>>> dereferencing the null pointer 'stack'. Fix this by avoiding the
>>>> error exit path via label 'out_err' that will lead to the path_put
>>>> calls and instead just return the error code directly.
>>>>
>>>> Addresses-Coverity: ("Dereference after null check)"
>>>> Fixes: 4155c10a0309 ("ovl: clean up getting lower layers")
>>>> Signed-off-by: Colin Ian King <[email protected]>
>>>
>>>
>>> Which branch is that based on?
>>> Doesn't seem to apply to master nor next
>>
>> It was based on today's linux-next
>
> Yeah, it's actually
>
> Fixes: 73819e26c0f0 ("ovl: get rid of redundant members in struct ovl_fs")
>
> So I'll just fold your patch. There's still a change in the loop
> count for later errors, but that's okay, since
> ovl_lower_dir()/ovl_mount_dir_noesc() use the path_put_init() variant.
> Actually ovl_lower_dir() can get rid of that path_put_init()
> completely, since now the only caller will take care of that...
>
> Thanks for reporting!
>
> Miklos
>
Is there a reason for folding the fix and hence losing the Signed-off-by
tag?
Colin
On Thu, Jun 4, 2020 at 11:27 AM Colin Ian King <[email protected]> wrote:
>
> On 04/06/2020 08:25, Miklos Szeredi wrote:
> > On Wed, Jun 3, 2020 at 6:15 PM Colin Ian King <[email protected]> wrote:
> >>
> >> On 03/06/2020 17:11, Amir Goldstein wrote:
> >>> On Wed, Jun 3, 2020 at 6:46 PM Colin King <[email protected]> wrote:
> >>>>
> >>>> From: Colin Ian King <[email protected]>
> >>>>
> >>>> There are two error return paths where the call to path_put is
> >>>> dereferencing the null pointer 'stack'. Fix this by avoiding the
> >>>> error exit path via label 'out_err' that will lead to the path_put
> >>>> calls and instead just return the error code directly.
> >>>>
> >>>> Addresses-Coverity: ("Dereference after null check)"
> >>>> Fixes: 4155c10a0309 ("ovl: clean up getting lower layers")
> >>>> Signed-off-by: Colin Ian King <[email protected]>
> >>>
> >>>
> >>> Which branch is that based on?
> >>> Doesn't seem to apply to master nor next
> >>
> >> It was based on today's linux-next
> >
> > Yeah, it's actually
> >
> > Fixes: 73819e26c0f0 ("ovl: get rid of redundant members in struct ovl_fs")
> >
> > So I'll just fold your patch. There's still a change in the loop
> > count for later errors, but that's okay, since
> > ovl_lower_dir()/ovl_mount_dir_noesc() use the path_put_init() variant.
> > Actually ovl_lower_dir() can get rid of that path_put_init()
> > completely, since now the only caller will take care of that...
> >
> > Thanks for reporting!
> >
> > Miklos
> >
> Is there a reason for folding the fix and hence losing the Signed-off-by
> tag?
I generally prefer to fold small fixes for not yet merged patches. In
this case it's more of a personal preference, but in other cases it
might have an effect on bisectability.
Thanks,
Miklos