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Tue, 30 Jan 2024 11:26:50 -0800 (PST) Date: Tue, 30 Jan 2024 19:26:39 +0000 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Developer-Key: i=rdbabiera@google.com; a=openpgp; fpr=639A331F1A21D691815CE090416E17CA2BBBD5C8 X-Developer-Signature: v=1; a=openpgp-sha256; l=2174; i=rdbabiera@google.com; h=from:subject; bh=B2kjYhFbSp4GX9YZwdN8eIiOyb3LTIyipZNOAiaztKA=; b=owGbwMvMwCFW0bfok0KS4TbG02pJDKk7ffM60yYd+Lhl7s6oww+lN4scPhCRv2uN2+mdVaHLu PJ04l7O7ChlYRDjYJAVU2TR9c8zuHEldcsczhpjmDmsTCBDGLg4BWAin98wMvyM+/HxveTGZr7Z eyfIn1z480L5hIvGsScvC7ZJfWF9X/eIkWGRTL7e9FreQ1I5WwubPlhl6tTz7xXsPbjTsi0ze9b XSbwA X-Mailer: git-send-email 2.43.0.429.g432eaa2c6b-goog Message-ID: <20240130192638.3557409-2-rdbabiera@google.com> Subject: [PATCH v1] usb: typec: altmodes/displayport: add null pointer check for sysfs nodes From: RD Babiera To: rdbabiera@google.com, heikki.krogerus@linux.intel.com, gregkh@linuxfoundation.org Cc: badhri@google.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org The DisplayPort driver's sysfs nodes may be present to the userspace before typec_altmode_set_drvdata() completes in dp_altmode_probe. This means that a sysfs read can trigger a NULL pointer error by deferencing dp->hpd in hpd_show or dp->lock in pin_assignment_show, as dev_get_drvdata() returns NULL in those cases. Verify dp drvdata is present in sysfs reads and writes before proceeding. Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode") Cc: stable@vger.kernel.org Signed-off-by: RD Babiera --- drivers/usb/typec/altmodes/displayport.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) base-commit: f1a27f081c1fa1eeebf38406e45f29636114470f diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c index 5a80776c7255..0423326219d8 100644 --- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -518,6 +518,9 @@ configuration_store(struct device *dev, struct device_attribute *attr, int con; int ret = 0; + if (!dp) + return -ENODEV; + con = sysfs_match_string(configurations, buf); if (con < 0) return con; @@ -563,6 +566,9 @@ static ssize_t configuration_show(struct device *dev, u8 cur; int i; + if (!dp) + return -ENODEV; + mutex_lock(&dp->lock); cap = DP_CAP_CAPABILITY(dp->alt->vdo); @@ -615,6 +621,9 @@ pin_assignment_store(struct device *dev, struct device_attribute *attr, u32 conf; int ret; + if (!dp) + return -ENODEV; + ret = sysfs_match_string(pin_assignments, buf); if (ret < 0) return ret; @@ -666,6 +675,9 @@ static ssize_t pin_assignment_show(struct device *dev, u8 cur; int i; + if (!dp) + return -ENODEV; + mutex_lock(&dp->lock); cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf)); @@ -698,6 +710,9 @@ static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char { struct dp_altmode *dp = dev_get_drvdata(dev); + if (!dp) + return -ENODEV; + return sysfs_emit(buf, "%d\n", dp->hpd); } static DEVICE_ATTR_RO(hpd);