From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Badhri Jagan Sridharan <badhri@google.com>
Cc: gregkh@linuxfoundation.org, amitsd@google.com,
kyletso@google.com, rdbabiera@google.com,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [PATCH v1] usb: typec: tcpm: Defensively bound altmode array accesses
Date: Tue, 30 Jun 2026 12:55:27 +0300 [thread overview]
Message-ID: <akOSj0k8GTHh5fUy@kuha> (raw)
In-Reply-To: <20260629225729.2749896-1-badhri@google.com>
On Mon, Jun 29, 2026 at 10:57:29PM +0000, Badhri Jagan Sridharan wrote:
> While svdm_consume_modes() already prevents mode_data.altmodes from
> exceeding ALTMODE_DISCOVERY_MAX during SVDM discovery, defensively
> bounding array iteration indices against ALTMODE_DISCOVERY_MAX in altmode
> registration and unregistration helpers guarantees protection against
> out-of-bounds accesses in the event of memory corruption.
>
> Ensure that tcpm_register_plug_altmodes() is also bounded alongside
> tcpm_register_partner_altmodes() and tcpm_unregister_altmodes.
>
> Assisted-by: Antigravity:gemini-3.5-flash
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
> Reviewed-by: RD Babiera <rdbabiera@google.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
> drivers/usb/typec/tcpm/tcpm.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 7ef746a90a17..c9ac9381b17c 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -2029,7 +2029,7 @@ static void tcpm_register_partner_altmodes(struct tcpm_port *port)
> if (!port->partner)
> return;
>
> - for (i = 0; i < modep->altmodes; i++) {
> + for (i = 0; i < modep->altmodes && i < ALTMODE_DISCOVERY_MAX; i++) {
> altmode = typec_partner_register_altmode(port->partner,
> &modep->altmode_desc[i]);
> if (IS_ERR(altmode)) {
> @@ -2047,9 +2047,10 @@ static void tcpm_register_plug_altmodes(struct tcpm_port *port)
> struct typec_altmode *altmode;
> int i;
>
> - typec_plug_set_num_altmodes(port->plug_prime, modep->altmodes);
> + typec_plug_set_num_altmodes(port->plug_prime,
> + min(modep->altmodes, ALTMODE_DISCOVERY_MAX));
>
> - for (i = 0; i < modep->altmodes; i++) {
> + for (i = 0; i < modep->altmodes && i < ALTMODE_DISCOVERY_MAX; i++) {
> altmode = typec_plug_register_altmode(port->plug_prime,
> &modep->altmode_desc[i]);
> if (IS_ERR(altmode)) {
> @@ -4891,11 +4892,11 @@ static void tcpm_unregister_altmodes(struct tcpm_port *port)
> struct pd_mode_data *modep_prime = &port->mode_data_prime;
> int i;
>
> - for (i = 0; i < modep->altmodes; i++) {
> + for (i = 0; i < modep->altmodes && i < ALTMODE_DISCOVERY_MAX; i++) {
> typec_unregister_altmode(port->partner_altmode[i]);
> port->partner_altmode[i] = NULL;
> }
> - for (i = 0; i < modep_prime->altmodes; i++) {
> + for (i = 0; i < modep_prime->altmodes && i < ALTMODE_DISCOVERY_MAX; i++) {
> typec_unregister_altmode(port->plug_prime_altmode[i]);
> port->plug_prime_altmode[i] = NULL;
> }
>
> base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
> --
> 2.55.0.rc0.799.gd6f94ed593-goog
--
heikki
prev parent reply other threads:[~2026-06-30 9:55 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-29 22:57 [PATCH v1] usb: typec: tcpm: Defensively bound altmode array accesses Badhri Jagan Sridharan
2026-06-30 9:55 ` Heikki Krogerus [this message]
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