In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
returns NULL when fails. So 'arg' should be checked.
Signed-off-by: Gen Zhang <[email protected]>
---
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3ec702c..5a9e959 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2635,6 +2635,8 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
*q++ = c;
}
arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
+ if (!arg)
+ return 0;
}
rc = selinux_add_opt(token, arg, mnt_opts);
if (unlikely(rc)) {
On Wed, May 29, 2019 at 8:55 PM Gen Zhang <[email protected]> wrote:
>
> In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
> returns NULL when fails. So 'arg' should be checked.
>
> Signed-off-by: Gen Zhang <[email protected]>
> ---
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 3ec702c..5a9e959 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2635,6 +2635,8 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
> *q++ = c;
> }
> arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
> + if (!arg)
> + return 0;
The routine seems to return 0 on success, why would it return 0 on ENOMEM?
> }
> rc = selinux_add_opt(token, arg, mnt_opts);
> if (unlikely(rc)) {
On Wed, May 29, 2019 at 09:39:50PM -0700, William Roberts wrote:
> On Wed, May 29, 2019 at 8:55 PM Gen Zhang <[email protected]> wrote:
> >
> > In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
> > returns NULL when fails. So 'arg' should be checked.
> >
> > Signed-off-by: Gen Zhang <[email protected]>
> > ---
> > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> > index 3ec702c..5a9e959 100644
> > --- a/security/selinux/hooks.c
> > +++ b/security/selinux/hooks.c
> > @@ -2635,6 +2635,8 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
> > *q++ = c;
> > }
> > arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
> > + if (!arg)
> > + return 0;
>
> The routine seems to return 0 on success, why would it return 0 on ENOMEM?
>
Thanks for your reply, William. I re-examined the source code and didn't
figure out what the return value should be in this situation. Could it
be a -ENOMEM? Do you have any idea?
Thanks
Gen
> > }
> > rc = selinux_add_opt(token, arg, mnt_opts);
> > if (unlikely(rc)) {
On Thu, May 30, 2019 at 5:53 AM Gen Zhang <[email protected]> wrote:
> In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
> returns NULL when fails. So 'arg' should be checked.
>
> Signed-off-by: Gen Zhang <[email protected]>
Since it looks like you are going to respin this patch, please add:
Fixes: 99dbbb593fe6 ("selinux: rewrite selinux_sb_eat_lsm_opts()")
to the commit message so that there is a record of which commit
introduced the issue (then it can be picked up automatically for
backport into the relevant stable kernels).
Thanks for spotting the issue and sending the patch(es)!
> ---
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 3ec702c..5a9e959 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2635,6 +2635,8 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
> *q++ = c;
> }
> arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
> + if (!arg)
> + return 0;
> }
> rc = selinux_add_opt(token, arg, mnt_opts);
> if (unlikely(rc)) {
--
Ondrej Mosnacek <omosnace at redhat dot com>
Software Engineer, Security Technologies
Red Hat, Inc.
In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
returns NULL when fails. So 'arg' should be checked.
Signed-off-by: Gen Zhang <[email protected]>
Fixes: 99dbbb593fe6 ("selinux: rewrite selinux_sb_eat_lsm_opts()")
---
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3ec702c..5a9e959 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2635,6 +2635,8 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
*q++ = c;
}
arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
+ if (!arg)
+ return -ENOMEM;
}
rc = selinux_add_opt(token, arg, mnt_opts);
if (unlikely(rc)) {
On Thu, May 30, 2019 at 10:51 AM Gen Zhang <[email protected]> wrote:
> In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
> returns NULL when fails. So 'arg' should be checked.
>
> Signed-off-by: Gen Zhang <[email protected]>
> Fixes: 99dbbb593fe6 ("selinux: rewrite selinux_sb_eat_lsm_opts()")
> ---
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 3ec702c..5a9e959 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2635,6 +2635,8 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
> *q++ = c;
> }
> arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
> + if (!arg)
> + return -ENOMEM;
> }
> rc = selinux_add_opt(token, arg, mnt_opts);
> if (unlikely(rc)) {
Looking at the callers of security_sb_eat_lsm_opts() (which is the
function that eventually calls the selinux_sb_eat_lsm_opts() hook),
-ENOMEM should be appropriate here.
Reviewed-by: Ondrej Mosnacek <[email protected]>
--
Ondrej Mosnacek <omosnace at redhat dot com>
Software Engineer, Security Technologies
Red Hat, Inc.
On Thu, May 30, 2019 at 4:52 AM Ondrej Mosnacek <[email protected]> wrote:
>
> On Thu, May 30, 2019 at 10:51 AM Gen Zhang <[email protected]> wrote:
> > In selinux_sb_eat_lsm_opts(), 'arg' is allocated by kmemdup_nul(). It
> > returns NULL when fails. So 'arg' should be checked.
> >
> > Signed-off-by: Gen Zhang <[email protected]>
> > Fixes: 99dbbb593fe6 ("selinux: rewrite selinux_sb_eat_lsm_opts()")
> > ---
> > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> > index 3ec702c..5a9e959 100644
> > --- a/security/selinux/hooks.c
> > +++ b/security/selinux/hooks.c
> > @@ -2635,6 +2635,8 @@ static int selinux_sb_eat_lsm_opts(char *options, void **mnt_opts)
> > *q++ = c;
> > }
> > arg = kmemdup_nul(arg, q - arg, GFP_KERNEL);
> > + if (!arg)
> > + return -ENOMEM;
Yeah -ENOMEM is correct here. Ack by me.
> > }
> > rc = selinux_add_opt(token, arg, mnt_opts);
> > if (unlikely(rc)) {
>
> Looking at the callers of security_sb_eat_lsm_opts() (which is the
> function that eventually calls the selinux_sb_eat_lsm_opts() hook),
> -ENOMEM should be appropriate here.
>
> Reviewed-by: Ondrej Mosnacek <[email protected]>
>
> --
> Ondrej Mosnacek <omosnace at redhat dot com>
> Software Engineer, Security Technologies
> Red Hat, Inc.