| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.4 49/88] virtio: 9p: correctly pass physical address to userspace for high pages | Date | Mon, 9 Jun 2014 17:24:59 -0700 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Will Deacon <will.deacon@arm.com>
commit 30d395b124c51db66d9f3ba0611cd62021afc392 upstream.
commit b9cdc88df8e63e81c723b82c286fc97f5d0dc325 upstream.
When using a virtio transport, the 9p net device may pass the physical address of a kernel buffer to userspace via a scatterlist inside a virtqueue. If the kernel buffer is mapped outside of the linear mapping (e.g. highmem), then virt_to_page will return a bogus value and we will populate the scatterlist with junk.
This patch uses kmap_to_page when populating the page array for a kernel buffer.
Cc: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- net/9p/trans_virtio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -39,6 +39,7 @@ #include <linux/inet.h> #include <linux/idr.h> #include <linux/file.h> +#include <linux/highmem.h> #include <linux/slab.h> #include <net/9p/9p.h> #include <linux/parser.h> @@ -325,7 +326,7 @@ static int p9_get_mapped_pages(struct vi int count = nr_pages; while (nr_pages) { s = rest_of_page(data); - pages[index++] = virt_to_page(data); + pages[index++] = kmap_to_page(data); data += s; nr_pages--; }
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