Commit 9e13ec61 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Joerg Roedel
Browse files

iommu/virtio: Add __counted_by for struct viommu_request and use struct_size() 



Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

While there, use struct_size() helper, instead of the open-coded
version, to calculate the size for the allocation of the whole
flexible structure, including of course, the flexible-array member.

This code was found with the help of Coccinelle, and audited and
fixed manually.

Signed-off-by: default avatarGustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: default avatarJustin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/ZSRFW0yDlDo8+at3@work


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 6465e260

drivers/iommu/virtio-iommu.c

+2 −2
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ struct viommu_request { 
	void				*writeback;

	unsigned int			write_offset;

	unsigned int			len;

	char				buf[];

	char				buf[] __counted_by(len);

};



#define VIOMMU_FAULT_RESV_MASK		0xffffff00
@@ -230,7 +230,7 @@ static int __viommu_add_req(struct viommu_dev *viommu, void *buf, size_t len, 
	if (write_offset <= 0)

		return -EINVAL;



	req = kzalloc(sizeof(*req) + len, GFP_ATOMIC);

	req = kzalloc(struct_size(req, buf, len), GFP_ATOMIC);

	if (!req)

		return -ENOMEM;