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a=openpgp; fpr=169DEB6C0BC3C46013D2C79F11A72EA01471D772 X-Proofpoint-GUID: DavMJwp9ADytWePngWrxbukTY3gRrU5v X-Authority-Analysis: v=2.4 cv=dPczC+Zb c=1 sm=1 tr=0 ts=6ab129a6 cx=c_pps a=DUEm7b3gzWu7BqY5nP7+9g==:117 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=gowsoOTTUOVcmtlkKump:22 a=c92rfblmAAAA:8 a=VwQbUJbxAAAA:8 a=bC-a23v3AAAA:8 a=EUspDBNiAAAA:8 a=SbMoOReDAAAA:8 a=1lYKK9CxXCv_yy53LZkA:9 a=QEXdDO2ut3YA:10 a=-aSRE8QhW-JAV6biHavz:22 a=GvGzcOZaWPEFPQC_NcjD:22 a=FO4_E8m0qiDe52t0p3_H:22 a=9N8DiX9at80mjW8aGMU2:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTIxMDE4NyBTYWx0ZWRfX3zMi04VFF+Uu /AYpLGRvEy8N0FEZjIKVqWDzXcKrWJVQy+CXi1+YZ4VGBLj53d4rhJqlyYlXk7oqPJw40NZjQMm iocku/onvyBin/53/OxW6Eft+/tVMsf2H0bkqsHri7s+C8BNfI6uYSr9PYCFtMmtdiXiyb5RQu0 RxVYQHpOeh7XiotHebfzzWr6Cy2YKbI6Kw9r12oS6w3mJyrWaTJqbfM5NSD5XelVtGSgEsC9t/c NviSFvjWfP/l1q2lgD0h2kEZlTJMfn4wJNgIZNJ9fMmk/zlhqxNhyxHDIUnduxT44dO/Y6MNer4 2d20zTnC1FJYwX76jjN7PmoFWSDvBailnEaSuYdxRfR5/1Jc29vvwjrpRfGnTNLMiYrpP5J8oRS VPTQyKUJEL66OcRjUfN5+gRL/M4IfSAAhnflLg24aTuuxndBnN//EBvZMqtvfbCyrEbiRQ+aIFO fzbq/5/K7A1yEmPAPQw== X-Proofpoint-Spam-Info: AW1haW4tMjYwOTIxMDE4NyBTYWx0ZWRfX7edY6yBmZnmK 6buPL5RC961CoEfMbXId/+651DT1lsHSoTThCaxIIx0w0B41oUqopK1BxVkVg1mmmzc8GUtaDWC qax+moX5dRNLnvdaXb4cOR/SUG6Z2Ac= X-Proofpoint-ORIG-GUID: DavMJwp9ADytWePngWrxbukTY3gRrU5v X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-21_04,2026-09-16_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 malwarescore=0 phishscore=0 lowpriorityscore=0 priorityscore=1501 bulkscore=0 clxscore=1015 adultscore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609210187 If we fail to acquire the GPIO chip guard in gpio_desc_to_lineinfo(), we return immediately before zeroing the info struct we'll end up passing to the user-space later in lineinfo_get_v1(). This may leak the kernel stack contents. Make gpio_desc_to_lineinfo() return int so that the -ENODEV returned on failure to acquire the guard can be propagated to the callers. While not strictly necessary: move the memset() before trying to acquire the SRCU read lock too for good measure. Fixes: d83cee3d2bb1 ("gpio: protect the pointer to gpio_chip in gpio_device= with SRCU") Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://sashiko.dev/#/patchset/20260912123529.7951-1-tzungbi%40kern= el.org?part=3D3 Signed-off-by: Bartosz Golaszewski --- Changes in v2: - Make gpio_desc_to_lineinfo() return an integer return value so that the error code returned in case of a failure to acquire the guard can be propagated down the stack - Link to v1: https://patch.msgid.link/20260917-gpio-cdev-stack-leak-fixes-= v1-1-2bb52879e49c@oss.qualcomm.com --- drivers/gpio/gpiolib-cdev.c | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index b5da6e8566dcd777ef4e7784989b722416c07fd3..f8ef7367b8c856986237dcc3a42= 5a7152fc2db20 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -2174,18 +2174,19 @@ static void gpio_v2_line_info_changed_to_v1( =20 #endif /* CONFIG_GPIO_CDEV_V1 */ =20 -static void gpio_desc_to_lineinfo(struct gpio_desc *desc, - struct gpio_v2_line_info *info, bool atomic) +static int gpio_desc_to_lineinfo(struct gpio_desc *desc, + struct gpio_v2_line_info *info, bool atomic) { u32 debounce_period_us; unsigned long dflags; const char *label; =20 + memset(info, 0, sizeof(*info)); + CLASS(gpio_chip_guard, guard)(desc); if (!guard.gc) - return; + return -ENODEV; =20 - memset(info, 0, sizeof(*info)); info->offset =3D gpiod_hwgpio(desc); =20 if (desc->name) @@ -2260,6 +2261,8 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *d= esc, debounce_period_us; info->num_attrs++; } + + return 0; } =20 struct gpio_chardev_data { @@ -2311,6 +2314,7 @@ static int lineinfo_get_v1(struct gpio_chardev_data *= cdev, void __user *ip, struct gpio_desc *desc; struct gpioline_info lineinfo; struct gpio_v2_line_info lineinfo_v2; + int ret; =20 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) return -EFAULT; @@ -2328,7 +2332,10 @@ static int lineinfo_get_v1(struct gpio_chardev_data = *cdev, void __user *ip, return -EBUSY; } =20 - gpio_desc_to_lineinfo(desc, &lineinfo_v2, false); + ret =3D gpio_desc_to_lineinfo(desc, &lineinfo_v2, false); + if (ret) + return ret; + gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); =20 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { @@ -2346,6 +2353,7 @@ static int lineinfo_get(struct gpio_chardev_data *cde= v, void __user *ip, { struct gpio_desc *desc; struct gpio_v2_line_info lineinfo; + int ret; =20 if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) return -EFAULT; @@ -2365,7 +2373,10 @@ static int lineinfo_get(struct gpio_chardev_data *cd= ev, void __user *ip, if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) return -EBUSY; } - gpio_desc_to_lineinfo(desc, &lineinfo, false); + + ret =3D gpio_desc_to_lineinfo(desc, &lineinfo, false); + if (ret) + return ret; =20 if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { if (watch) @@ -2491,6 +2502,7 @@ static int lineinfo_changed_notify(struct notifier_bl= ock *nb, struct lineinfo_changed_ctx *ctx; struct gpio_desc *desc =3D data; struct file *fp; + int ret; =20 if (!test_bit(gpiod_hwgpio(desc), cdev->watched_lines)) return NOTIFY_DONE; @@ -2521,7 +2533,14 @@ static int lineinfo_changed_notify(struct notifier_b= lock *nb, =20 ctx->chg.event_type =3D action; ctx->chg.timestamp_ns =3D ktime_get_ns(); - gpio_desc_to_lineinfo(desc, &ctx->chg.info, true); + + ret =3D gpio_desc_to_lineinfo(desc, &ctx->chg.info, true); + if (ret) { + fput(fp); + pr_err("GPIO controller that generated the line info notification was re= moved\n"); + return NOTIFY_DONE; + } + /* Keep the GPIO device alive until we emit the event. */ ctx->gdev =3D gpio_device_get(desc->gdev); ctx->cdev =3D cdev; --- base-commit: 0d9d0dbf2fddcff5859d623e90ca73c4054276e1 change-id: 20260917-gpio-cdev-stack-leak-fixes-84ad8918a6e0 Best regards, --=20 Bartosz Golaszewski