drm/amdkfd: validate SVM ioctl nattr against buffer size

commit 045e0ff upstream.

Validate nattr field against the buffer size, preventing
out-of-bounds buffer access via user-controlled attribute count.

Reviewed-by: Amir Shetaia <Amir.Shetaia@amd.com>
Signed-off-by: Alysa Liu <Alysa.Liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 5eca8bf)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: amd-alysaliu

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

@@ -26,6 +26,7 @@
 #include <linux/err.h>
 #include <linux/fs.h>
 #include <linux/file.h>
+#include <linux/overflow.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
@@ -1705,6 +1706,16 @@ static int kfd_ioctl_smi_events(struct file *filep,
 	return kfd_smi_event_open(pdd->dev, &args->anon_fd);
 }
 
+static int kfd_ioctl_svm_validate(void *kdata, unsigned int usize)
+{
+	struct kfd_ioctl_svm_args *args = kdata;
+	size_t expected = struct_size(args, attrs, args->nattr);
+
+	if (expected == SIZE_MAX || usize < expected)
+		return -EINVAL;
+	return 0;
+}
+
 #if IS_ENABLED(CONFIG_HSA_AMD_SVM)
 
 static int kfd_ioctl_set_xnack_mode(struct file *filep,
@@ -3128,7 +3139,11 @@ static int kfd_ioctl_set_debug_trap(struct file *filep, struct kfd_process *p, v
 
 #define AMDKFD_IOCTL_DEF(ioctl, _func, _flags) \
 	[_IOC_NR(ioctl)] = {.cmd = ioctl, .func = _func, .flags = _flags, \
-			    .cmd_drv = 0, .name = #ioctl}
+			    .validate = NULL, .cmd_drv = 0, .name = #ioctl}
+
+#define AMDKFD_IOCTL_DEF_V(ioctl, _func, _validate, _flags) \
+	[_IOC_NR(ioctl)] = {.cmd = ioctl, .func = _func, .flags = _flags, \
+			    .validate = _validate, .cmd_drv = 0, .name = #ioctl}
 
 /** Ioctl table */
 static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = {
@@ -3225,7 +3240,8 @@ static const struct amdkfd_ioctl_desc amdkfd_ioctls[] = {
 	AMDKFD_IOCTL_DEF(AMDKFD_IOC_SMI_EVENTS,
 			kfd_ioctl_smi_events, 0),
 
-	AMDKFD_IOCTL_DEF(AMDKFD_IOC_SVM, kfd_ioctl_svm, 0),
+	AMDKFD_IOCTL_DEF_V(AMDKFD_IOC_SVM, kfd_ioctl_svm,
+			   kfd_ioctl_svm_validate, 0),
 
 	AMDKFD_IOCTL_DEF(AMDKFD_IOC_SET_XNACK_MODE,
 			kfd_ioctl_set_xnack_mode, 0),
@@ -3347,6 +3363,12 @@ static long kfd_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 		memset(kdata, 0, usize);
 	}
 
+	if (ioctl->validate) {
+		retcode = ioctl->validate(kdata, usize);
+		if (retcode)
+			goto err_i1;
+	}
+
 	retcode = func(filep, process, kdata);
 
 	if (cmd & IOC_OUT)

drivers/gpu/drm/amd/amdkfd/kfd_priv.h

@@ -1006,10 +1006,13 @@ extern struct srcu_struct kfd_processes_srcu;
 typedef int amdkfd_ioctl_t(struct file *filep, struct kfd_process *p,
 				void *data);
 
+typedef int amdkfd_ioctl_validate_t(void *kdata, unsigned int usize);
+
 struct amdkfd_ioctl_desc {
 	unsigned int cmd;
 	int flags;
 	amdkfd_ioctl_t *func;
+	amdkfd_ioctl_validate_t *validate;
 	unsigned int cmd_drv;
 	const char *name;
 };