From 313ebe47d75558511aa1237b6e35c663b5c0ec6f Mon Sep 17 00:00:00 2001 From: Philipp Stanner Date: Wed, 20 Sep 2023 14:36:09 +0200 Subject: string.h: add array-wrappers for (v)memdup_user() 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 Signed-off-by: Philipp Stanner Reviewed-by: Andy Shevchenko Reviewed-by: Kees Cook Reviewed-by: Zack Rusin Signed-off-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20230920123612.16914-3-pstanner@redhat.com --- include/linux/string.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/include/linux/string.h b/include/linux/string.h index dbfc66400050..debf4ef1098f 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -5,7 +5,9 @@ #include /* for inline */ #include /* for size_t */ #include /* for NULL */ +#include /* for ERR_PTR() */ #include /* for E2BIG */ +#include /* for check_mul_overflow() */ #include #include @@ -14,6 +16,44 @@ 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 */ -- cgit From 569c8d82f95eb5993c84fb61a649a9c4ddd208b3 Mon Sep 17 00:00:00 2001 From: Philipp Stanner Date: Wed, 20 Sep 2023 14:36:10 +0200 Subject: kernel: kexec: copy user-array safely Currently, there is no overflow-check with memdup_user(). Use the new function memdup_array_user() instead of memdup_user() for duplicating the user-space array safely. Suggested-by: David Airlie Signed-off-by: Philipp Stanner Acked-by: Baoquan He Reviewed-by: Kees Cook Reviewed-by: Zack Rusin Signed-off-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20230920123612.16914-4-pstanner@redhat.com --- kernel/kexec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/kexec.c b/kernel/kexec.c index 107f355eac10..8f35a5a42af8 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -247,7 +247,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, ((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT)) return -EINVAL; - ksegments = memdup_user(segments, nr_segments * sizeof(ksegments[0])); + ksegments = memdup_array_user(segments, nr_segments, sizeof(ksegments[0])); if (IS_ERR(ksegments)) return PTR_ERR(ksegments); -- cgit From ca0776571d3163bd03b3e8c9e3da936abfaecbf6 Mon Sep 17 00:00:00 2001 From: Philipp Stanner Date: Wed, 20 Sep 2023 14:36:11 +0200 Subject: kernel: watch_queue: copy user-array safely Currently, there is no overflow-check with memdup_user(). Use the new function memdup_array_user() instead of memdup_user() for duplicating the user-space array safely. Suggested-by: David Airlie Signed-off-by: Philipp Stanner Reviewed-by: Kees Cook Reviewed-by: Zack Rusin Signed-off-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20230920123612.16914-5-pstanner@redhat.com --- kernel/watch_queue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c index d0b6b390ee42..778b4056700f 100644 --- a/kernel/watch_queue.c +++ b/kernel/watch_queue.c @@ -331,7 +331,7 @@ long watch_queue_set_filter(struct pipe_inode_info *pipe, filter.__reserved != 0) return -EINVAL; - tf = memdup_user(_filter->filters, filter.nr_filters * sizeof(*tf)); + tf = memdup_array_user(_filter->filters, filter.nr_filters, sizeof(*tf)); if (IS_ERR(tf)) return PTR_ERR(tf); -- cgit From f37d63e219c39199a59b8b8a211412ff27192830 Mon Sep 17 00:00:00 2001 From: Philipp Stanner Date: Wed, 20 Sep 2023 14:36:12 +0200 Subject: drm_lease.c: copy user-array safely Currently, there is no overflow-check with memdup_user(). Use the new function memdup_array_user() instead of memdup_user() for duplicating the user-space array safely. Suggested-by: David Airlie Signed-off-by: Philipp Stanner Reviewed-by: Kees Cook Reviewed-by: Zack Rusin Signed-off-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20230920123612.16914-6-pstanner@redhat.com --- drivers/gpu/drm/drm_lease.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c index 150fe1555068..94375c6a5425 100644 --- a/drivers/gpu/drm/drm_lease.c +++ b/drivers/gpu/drm/drm_lease.c @@ -510,8 +510,8 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, /* Handle leased objects, if any */ idr_init(&leases); if (object_count != 0) { - object_ids = memdup_user(u64_to_user_ptr(cl->object_ids), - array_size(object_count, sizeof(__u32))); + object_ids = memdup_array_user(u64_to_user_ptr(cl->object_ids), + object_count, sizeof(__u32)); if (IS_ERR(object_ids)) { ret = PTR_ERR(object_ids); idr_destroy(&leases); -- cgit From 06ab64a0d836ac430c5f94669710a78aa43942cb Mon Sep 17 00:00:00 2001 From: Philipp Stanner Date: Wed, 20 Sep 2023 14:36:13 +0200 Subject: drm: vmwgfx_surface.c: copy user-array safely Currently, there is no overflow-check with memdup_user(). Use the new function memdup_array_user() instead of memdup_user() for duplicating the user-space array safely. Suggested-by: David Airlie Signed-off-by: Philipp Stanner Reviewed-by: Kees Cook Reviewed-by: Zack Rusin Signed-off-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20230920123612.16914-7-pstanner@redhat.com --- drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c index 5db403ee8261..9be185b094cb 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c @@ -777,9 +777,9 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data, sizeof(metadata->mip_levels)); metadata->num_sizes = num_sizes; metadata->sizes = - memdup_user((struct drm_vmw_size __user *)(unsigned long) + memdup_array_user((struct drm_vmw_size __user *)(unsigned long) req->size_addr, - sizeof(*metadata->sizes) * metadata->num_sizes); + metadata->num_sizes, sizeof(*metadata->sizes)); if (IS_ERR(metadata->sizes)) { ret = PTR_ERR(metadata->sizes); goto out_no_sizes; -- cgit