From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- drivers/input/input-compat.c | 163 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 163 insertions(+) create mode 100644 drivers/input/input-compat.c (limited to 'drivers/input/input-compat.c') diff --git a/drivers/input/input-compat.c b/drivers/input/input-compat.c new file mode 100644 index 000000000..a5043193e --- /dev/null +++ b/drivers/input/input-compat.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 32bit compatibility wrappers for the input subsystem. + * + * Very heavily based on evdev.c - Copyright (c) 1999-2002 Vojtech Pavlik + */ + +#include +#include +#include +#include "input-compat.h" + +#ifdef CONFIG_COMPAT + +int input_event_from_user(const char __user *buffer, + struct input_event *event) +{ + if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) { + struct input_event_compat compat_event; + + if (copy_from_user(&compat_event, buffer, + sizeof(struct input_event_compat))) + return -EFAULT; + + event->input_event_sec = compat_event.sec; + event->input_event_usec = compat_event.usec; + event->type = compat_event.type; + event->code = compat_event.code; + event->value = compat_event.value; + + } else { + if (copy_from_user(event, buffer, sizeof(struct input_event))) + return -EFAULT; + } + + return 0; +} + +int input_event_to_user(char __user *buffer, + const struct input_event *event) +{ + if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) { + struct input_event_compat compat_event; + + compat_event.sec = event->input_event_sec; + compat_event.usec = event->input_event_usec; + compat_event.type = event->type; + compat_event.code = event->code; + compat_event.value = event->value; + + if (copy_to_user(buffer, &compat_event, + sizeof(struct input_event_compat))) + return -EFAULT; + + } else { + if (copy_to_user(buffer, event, sizeof(struct input_event))) + return -EFAULT; + } + + return 0; +} + +int input_ff_effect_from_user(const char __user *buffer, size_t size, + struct ff_effect *effect) +{ + if (in_compat_syscall()) { + struct ff_effect_compat *compat_effect; + + if (size != sizeof(struct ff_effect_compat)) + return -EINVAL; + + /* + * It so happens that the pointer which needs to be changed + * is the last field in the structure, so we can retrieve the + * whole thing and replace just the pointer. + */ + compat_effect = (struct ff_effect_compat *)effect; + + if (copy_from_user(compat_effect, buffer, + sizeof(struct ff_effect_compat))) + return -EFAULT; + + if (compat_effect->type == FF_PERIODIC && + compat_effect->u.periodic.waveform == FF_CUSTOM) + effect->u.periodic.custom_data = + compat_ptr(compat_effect->u.periodic.custom_data); + } else { + if (size != sizeof(struct ff_effect)) + return -EINVAL; + + if (copy_from_user(effect, buffer, sizeof(struct ff_effect))) + return -EFAULT; + } + + return 0; +} + +int input_bits_to_string(char *buf, int buf_size, unsigned long bits, + bool skip_empty) +{ + int len = 0; + + if (in_compat_syscall()) { + u32 dword = bits >> 32; + if (dword || !skip_empty) + len += snprintf(buf, buf_size, "%x ", dword); + + dword = bits & 0xffffffffUL; + if (dword || !skip_empty || len) + len += snprintf(buf + len, max(buf_size - len, 0), + "%x", dword); + } else { + if (bits || !skip_empty) + len += snprintf(buf, buf_size, "%lx", bits); + } + + return len; +} + +#else + +int input_event_from_user(const char __user *buffer, + struct input_event *event) +{ + if (copy_from_user(event, buffer, sizeof(struct input_event))) + return -EFAULT; + + return 0; +} + +int input_event_to_user(char __user *buffer, + const struct input_event *event) +{ + if (copy_to_user(buffer, event, sizeof(struct input_event))) + return -EFAULT; + + return 0; +} + +int input_ff_effect_from_user(const char __user *buffer, size_t size, + struct ff_effect *effect) +{ + if (size != sizeof(struct ff_effect)) + return -EINVAL; + + if (copy_from_user(effect, buffer, sizeof(struct ff_effect))) + return -EFAULT; + + return 0; +} + +int input_bits_to_string(char *buf, int buf_size, unsigned long bits, + bool skip_empty) +{ + return bits || !skip_empty ? + snprintf(buf, buf_size, "%lx", bits) : 0; +} + +#endif /* CONFIG_COMPAT */ + +EXPORT_SYMBOL_GPL(input_event_from_user); +EXPORT_SYMBOL_GPL(input_event_to_user); +EXPORT_SYMBOL_GPL(input_ff_effect_from_user); -- cgit v1.3.1