[PATCH 5.10 1/3] string.h: add array-wrappers for (v)memdup_user()

[PATCH 5.10 1/3] string.h: add array-wrappers for (v)memdup_user()

[Roman Demidov]

From: Philipp Stanner <pstanner@redhat.com>

commit 313ebe47d75558511aa1237b6e35c663b5c0ec6f upstream.

Currently, user array duplications are sometimes done without an
overflow check. Sometimes the checks are done manually; sometimes the
array size is calculated with array_size() and sometimes by calculating
n * size directly in code.

Introduce wrappers for arrays for memdup_user() and vmemdup_user() to
provide a standardized and safe way for duplicating user arrays.

This is both for new code as well as replacing usage of (v)memdup_user()
in existing code that uses, e.g., n * size to calculate array sizes.

Suggested-by: David Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230920123612.16914-3-pstanner@redhat.com
Stable-dep-of: c833d6c7199c ("drm/amdgpu: Limit BO list entry count to prevent resource exhaustion")
Signed-off-by: Roman Demidov <roman.demidov.nn@gmail.com>
---
Backport fix for CVE-2026-23468

 include/linux/string.h | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/include/linux/string.h b/include/linux/string.h
index 98b053d9c700..85efd2b738ea 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -5,6 +5,8 @@
 #include <linux/compiler.h>	/* for inline */
 #include <linux/types.h>	/* for size_t */
 #include <linux/stddef.h>	/* for NULL */
+#include <linux/err.h>		/* for ERR_PTR() */
+#include <linux/overflow.h>	/* for check_mul_overflow() */
 #include <stdarg.h>
 #include <uapi/linux/string.h>
 
@@ -13,6 +15,44 @@ extern void *memdup_user(const void __user *, size_t);
 extern void *vmemdup_user(const void __user *, size_t);
 extern void *memdup_user_nul(const void __user *, size_t);
 
+/**
+ * memdup_array_user - duplicate array from user space
+ * @src: source address in user space
+ * @n: number of array members to copy
+ * @size: size of one array member
+ *
+ * Return: an ERR_PTR() on failure. Result is physically
+ * contiguous, to be freed by kfree().
+ */
+static inline void *memdup_array_user(const void __user *src, size_t n, size_t size)
+{
+	size_t nbytes;
+
+	if (check_mul_overflow(n, size, &nbytes))
+		return ERR_PTR(-EOVERFLOW);
+
+	return memdup_user(src, nbytes);
+}
+
+/**
+ * vmemdup_array_user - duplicate array from user space
+ * @src: source address in user space
+ * @n: number of array members to copy
+ * @size: size of one array member
+ *
+ * Return: an ERR_PTR() on failure. Result may be not
+ * physically contiguous. Use kvfree() to free.
+ */
+static inline void *vmemdup_array_user(const void __user *src, size_t n, size_t size)
+{
+	size_t nbytes;
+
+	if (check_mul_overflow(n, size, &nbytes))
+		return ERR_PTR(-EOVERFLOW);
+
+	return vmemdup_user(src, nbytes);
+}
+
 /*
  * Include machine specific inline routines
  */
-- 
2.53.0

[PATCH 5.10 2/3] drm/amdgpu: Use vmemdup_array_user in amdgpu_bo_create_list_entry_array

[Roman Demidov]

From: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>

commit c4ac100e9ae252b09986766ad23b1f83ca3a369d upstream.

Replace kvmalloc_array() + copy_from_user() with vmemdup_array_user() on
the fast path.

This shrinks the source code and improves separation between the kernel
and userspace slabs.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Fang Wang <32840572@qq.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Stable-dep-of: c833d6c7199c ("drm/amdgpu: Limit BO list entry count to prevent resource exhaustion")
Signed-off-by: Roman Demidov <roman.demidov.nn@gmail.com>
---
Backport fix for CVE-2026-23468

 drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c | 41 +++++++++------------
 1 file changed, 17 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
index 9fb8012007e2..22d7b7c504db 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
@@ -224,43 +224,36 @@ void amdgpu_bo_list_put(struct amdgpu_bo_list *list)
 int amdgpu_bo_create_list_entry_array(struct drm_amdgpu_bo_list_in *in,
 				      struct drm_amdgpu_bo_list_entry **info_param)
 {
-	const void __user *uptr = u64_to_user_ptr(in->bo_info_ptr);
 	const uint32_t info_size = sizeof(struct drm_amdgpu_bo_list_entry);
+	const void __user *uptr = u64_to_user_ptr(in->bo_info_ptr);
+	const uint32_t bo_info_size = in->bo_info_size;
+	const uint32_t bo_number = in->bo_number;
 	struct drm_amdgpu_bo_list_entry *info;
-	int r;
-
-	info = kvmalloc_array(in->bo_number, info_size, GFP_KERNEL);
-	if (!info)
-		return -ENOMEM;
 
 	/* copy the handle array from userspace to a kernel buffer */
-	r = -EFAULT;
-	if (likely(info_size == in->bo_info_size)) {
-		unsigned long bytes = in->bo_number *
-			in->bo_info_size;
-
-		if (copy_from_user(info, uptr, bytes))
-			goto error_free;
-
+	if (likely(info_size == bo_info_size)) {
+		info = vmemdup_array_user(uptr, bo_number, info_size);
+		if (IS_ERR(info))
+			return PTR_ERR(info);
 	} else {
-		unsigned long bytes = min(in->bo_info_size, info_size);
+		const uint32_t bytes = min(bo_info_size, info_size);
 		unsigned i;
 
-		memset(info, 0, in->bo_number * info_size);
-		for (i = 0; i < in->bo_number; ++i) {
-			if (copy_from_user(&info[i], uptr, bytes))
-				goto error_free;
+		info = kvmalloc_array(bo_number, info_size, GFP_KERNEL);
+		if (!info)
+			return -ENOMEM;
 
-			uptr += in->bo_info_size;
+		memset(info, 0, bo_number * info_size);
+		for (i = 0; i < bo_number; ++i, uptr += bo_info_size) {
+			if (copy_from_user(&info[i], uptr, bytes)) {
+				kvfree(info);
+				return -EFAULT;
+			}
 		}
 	}
 
 	*info_param = info;
 	return 0;
-
-error_free:
-	kvfree(info);
-	return r;
 }
 
 int amdgpu_bo_list_ioctl(struct drm_device *dev, void *data,
-- 
2.53.0

[PATCH 5.10 3/3] drm/amdgpu: Limit BO list entry count to prevent resource exhaustion

[Roman Demidov]

From: "Jesse.Zhang" <Jesse.Zhang@amd.com>

commit 6270b1a5dab94665d7adce3dc78bc9066ed28bdd upstream.

Userspace can pass an arbitrary number of BO list entries via the
bo_number field. Although the previous multiplication overflow check
prevents out-of-bounds allocation, a large number of entries could still
cause excessive memory allocation (up to potentially gigabytes) and
unnecessarily long list processing times.

Introduce a hard limit of 128k entries per BO list, which is more than
sufficient for any realistic use case (e.g., a single list containing all
buffers in a large scene). This prevents memory exhaustion attacks and
ensures predictable performance.

Return -EINVAL if the requested entry count exceeds the limit

Reviewed-by: Christian König <christian.koenig@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Jesse Zhang <jesse.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 688b87d39e0aa8135105b40dc167d74b5ada5332)
Cc: stable@vger.kernel.org
Signed-off-by: Fang Wang <32840572@qq.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Roman Demidov <roman.demidov.nn@gmail.com>
---
Backport fix for CVE-2026-23468

 drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
index 22d7b7c504db..ca0d82be5c9c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
@@ -35,6 +35,7 @@
 
 #define AMDGPU_BO_LIST_MAX_PRIORITY	32u
 #define AMDGPU_BO_LIST_NUM_BUCKETS	(AMDGPU_BO_LIST_MAX_PRIORITY + 1)
+#define AMDGPU_BO_LIST_MAX_ENTRIES	(128 * 1024)
 
 static void amdgpu_bo_list_free_rcu(struct rcu_head *rcu)
 {
@@ -230,6 +231,9 @@ int amdgpu_bo_create_list_entry_array(struct drm_amdgpu_bo_list_in *in,
 	const uint32_t bo_number = in->bo_number;
 	struct drm_amdgpu_bo_list_entry *info;
 
+	if (bo_number > AMDGPU_BO_LIST_MAX_ENTRIES)
+		return -EINVAL;
+
 	/* copy the handle array from userspace to a kernel buffer */
 	if (likely(info_size == bo_info_size)) {
 		info = vmemdup_array_user(uptr, bo_number, info_size);
-- 
2.53.0