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xen/gntalloc: Replace UAPI 1-element array

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Without changing the structure size (since it is UAPI), add a proper
flexible array member, and reference it in the kernel so that it will
not be trip the array-bounds sanitizer[1].

Link: https://github.com/KSPP/linux/issues/113 [1]
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: xen-devel@lists.xenproject.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20240206170320.work.437-kees@kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Kees Cook 2024-02-06 09:03:24 -08:00 committed by Juergen Gross
parent b0f2f82c9c
commit bf5802238d
2 changed files with 5 additions and 2 deletions
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2
drivers/xen/gntalloc.c
View File

@ -317,7 +317,7 @@ static long gntalloc_ioctl_alloc(struct gntalloc_file_private_data *priv,
rc = -EFAULT;
goto out_free;
}
if (copy_to_user(arg->gref_ids, gref_ids,
if (copy_to_user(arg->gref_ids_flex, gref_ids,
sizeof(gref_ids[0]) * op.count)) {
rc = -EFAULT;
goto out_free;

5
include/uapi/xen/gntalloc.h
View File

@ -31,7 +31,10 @@ struct ioctl_gntalloc_alloc_gref {
__u64 index;
/* The grant references of the newly created grant, one per page */
/* Variable size, depending on count */
__u32 gref_ids[1];
union {
__u32 gref_ids[1];
__DECLARE_FLEX_ARRAY(__u32, gref_ids_flex);
};
};
#define GNTALLOC_FLAG_WRITABLE 1