[apparmor][PATCH] apparmor: fix incorrect success return value in unpack_tag_headers()

[apparmor][PATCH] apparmor: fix incorrect success return value in unpack_tag_headers()

[Massimiliano Pellizzer]

unpack_tag_headers() returns `true` (1) on success instead of 0.
Since it's caller unpack_tags() checks the return value with
`if (error)`, a non-zero success value is incorrectly treated as
a failure, causing tag header unpacking to always even if the data
is well-formed.

Change the success return in unpack_tag_headers() from `true` to 0.

Fixes: 3d28e2397af7 ("apparmor: add support loading per permission tagging")
Signed-off-by: Massimiliano Pellizzer <mpellizzer.dev@gmail.com>
---
 security/apparmor/policy_unpack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
index dc908e1f5a88..221208788025 100644
--- a/security/apparmor/policy_unpack.c
+++ b/security/apparmor/policy_unpack.c
@@ -825,7 +825,7 @@ static int unpack_tag_headers(struct aa_ext *e, struct aa_tags_struct *tags)
 	tags->hdrs.size = size;
 	tags->hdrs.table = hdrs;
 	AA_DEBUG(DEBUG_UNPACK, "headers %ld size %d", (long) hdrs, size);
-	return true;
+	return 0;
 
 fail:
 	kfree_sensitive(hdrs);
-- 
2.51.0

Re: [apparmor][PATCH] apparmor: fix incorrect success return value in unpack_tag_headers()

[John Johansen]

On 2/10/26 09:21, Massimiliano Pellizzer wrote:
> unpack_tag_headers() returns `true` (1) on success instead of 0.
> Since it's caller unpack_tags() checks the return value with
> `if (error)`, a non-zero success value is incorrectly treated as
> a failure, causing tag header unpacking to always even if the data
> is well-formed.
> 
> Change the success return in unpack_tag_headers() from `true` to 0.
> 
> Fixes: 3d28e2397af7 ("apparmor: add support loading per permission tagging")
> Signed-off-by: Massimiliano Pellizzer <mpellizzer.dev@gmail.com>

sorry, my reply to this seems to have failed. This was pulled in for the
7.0 PR

Acked-by: John Johansen <john.johansen@canonical.com>


> ---
>   security/apparmor/policy_unpack.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
> index dc908e1f5a88..221208788025 100644
> --- a/security/apparmor/policy_unpack.c
> +++ b/security/apparmor/policy_unpack.c
> @@ -825,7 +825,7 @@ static int unpack_tag_headers(struct aa_ext *e, struct aa_tags_struct *tags)
>   	tags->hdrs.size = size;
>   	tags->hdrs.table = hdrs;
>   	AA_DEBUG(DEBUG_UNPACK, "headers %ld size %d", (long) hdrs, size);
> -	return true;
> +	return 0;
>   
>   fail:
>   	kfree_sensitive(hdrs);

Re: [apparmor][PATCH] apparmor: fix incorrect success return value in unpack_tag_headers()

[Massimiliano Pellizzer]

On Wed, Mar 18, 2026 at 6:53 AM John Johansen
<john.johansen@canonical.com> wrote:
>
> On 2/10/26 09:21, Massimiliano Pellizzer wrote:
> > unpack_tag_headers() returns `true` (1) on success instead of 0.
> > Since it's caller unpack_tags() checks the return value with
> > `if (error)`, a non-zero success value is incorrectly treated as
> > a failure, causing tag header unpacking to always even if the data
> > is well-formed.
> >
> > Change the success return in unpack_tag_headers() from `true` to 0.
> >
> > Fixes: 3d28e2397af7 ("apparmor: add support loading per permission tagging")
> > Signed-off-by: Massimiliano Pellizzer <mpellizzer.dev@gmail.com>
>
> sorry, my reply to this seems to have failed. This was pulled in for the
> 7.0 PR
>
> Acked-by: John Johansen <john.johansen@canonical.com>
>
>
> > ---
> >   security/apparmor/policy_unpack.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c
> > index dc908e1f5a88..221208788025 100644
> > --- a/security/apparmor/policy_unpack.c
> > +++ b/security/apparmor/policy_unpack.c
> > @@ -825,7 +825,7 @@ static int unpack_tag_headers(struct aa_ext *e, struct aa_tags_struct *tags)
> >       tags->hdrs.size = size;
> >       tags->hdrs.table = hdrs;
> >       AA_DEBUG(DEBUG_UNPACK, "headers %ld size %d", (long) hdrs, size);
> > -     return true;
> > +     return 0;
> >
> >   fail:
> >       kfree_sensitive(hdrs);
>

Hello JJ,
I don't see this patch being part of v7.0-rc4:
$ git --no-pager log --grep "apparmor: fix incorrect success return
value in unpack"

I don't see the change applied to the apparmor-next branch either
(https://gitlab.com/apparmor/apparmor-kernel/-/blob/apparmor-next/security/apparmor/policy_unpack.c).

---
Massimiliano Pellizzer