kernel/linux.git/include/xen/grant_table.h, branch v6.12.80

xen/grants: support allocating consecutive grants

2022-06-06T06:54:35+00:00

For support of virtio via grant mappings in rare cases larger mappings using consecutive grants are needed. Support those by adding a bitmap of free grants. As consecutive grants will be needed only in very rare cases (e.g. when configuring a virtio device with a multi-page ring), optimize for the normal case of non-consecutive allocations. Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/1654197833-25362-3-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross

xen: switch gnttab_end_foreign_access() to take a struct page pointer

2022-05-27T09:05:29+00:00

Instead of a virtual kernel address use a pointer of the associated struct page as second parameter of gnttab_end_foreign_access(). Most users have that pointer available already and are creating the virtual address from it, risking problems in case the memory is located in highmem. gnttab_end_foreign_access() itself won't need to get the struct page from the address again. Suggested-by: Jan Beulich Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Juergen Gross

xen: update grant_table.h

2022-05-19T12:21:34+00:00

Update include/xen/interface/grant_table.h to its newest version. This allows to drop some private definitions in grant-table.c and include/xen/grant_table.h. Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross

xen/grant-table: remove readonly parameter from functions

2022-03-16T01:34:40+00:00

The gnttab_end_foreign_access() family of functions is taking a "readonly" parameter, which isn't used. Remove it from the function parameters. Signed-off-by: Juergen Gross Link: https://lore.kernel.org/r/20220311103429.12845-3-jgross@suse.com Reviewed-by: Jan Beulich Acked-by: Christian Schoenebeck Signed-off-by: Boris Ostrovsky

xen/grant-table: remove gnttab_transfer() functions

2022-03-16T01:34:04+00:00

All grant table operations related to the "transfer" functionality are unused currently. There have been users in the old days of the "Xen-o-Linux" kernel, but those didn't make it upstream. So remove the "transfer" related functions. Signed-off-by: Juergen Gross Link: https://lore.kernel.org/r/20220311103429.12845-2-jgross@suse.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky

xen/gnttab: fix gnttab_end_foreign_access() without page specified

2022-03-07T08:48:55+00:00

gnttab_end_foreign_access() is used to free a grant reference and optionally to free the associated page. In case the grant is still in use by the other side processing is being deferred. This leads to a problem in case no page to be freed is specified by the caller: the caller doesn't know that the page is still mapped by the other side and thus should not be used for other purposes. The correct way to handle this situation is to take an additional reference to the granted page in case handling is being deferred and to drop that reference when the grant reference could be freed finally. This requires that there are no users of gnttab_end_foreign_access() left directly repurposing the granted page after the call, as this might result in clobbered data or information leaks via the not yet freed grant reference. This is part of CVE-2022-23041 / XSA-396. Reported-by: Simon Gaiser Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich --- V4: - expand comment in header V5: - get page ref in case of kmalloc() failure, too

xen: remove gnttab_query_foreign_access()

2022-03-07T08:48:54+00:00

Remove gnttab_query_foreign_access(), as it is unused and unsafe to use. All previous use cases assumed a grant would not be in use after gnttab_query_foreign_access() returned 0. This information is useless in best case, as it only refers to a situation in the past, which could have changed already. Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich

xen/grant-table: add gnttab_try_end_foreign_access()

2022-03-07T08:48:54+00:00

Add a new grant table function gnttab_try_end_foreign_access(), which will remove and free a grant if it is not in use. Its main use case is to either free a grant if it is no longer in use, or to take some other action if it is still in use. This other action can be an error exit, or (e.g. in the case of blkfront persistent grant feature) some special handling. This is CVE-2022-23036, CVE-2022-23038 / part of XSA-396. Reported-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich --- V2: - new patch V4: - add comments to header (Jan Beulich)

Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}

2021-03-10T22:39:29+00:00

It's not helpful if every driver has to cook its own. Generalize xenbus'es INVALID_GRANT_HANDLE and pcifront's INVALID_GRANT_REF (which shouldn't have expanded to zero to begin with). Use the constants in p2m.c and gntdev.c right away, and update field types where necessary so they would match with the constants' types (albeit without touching struct ioctl_gntdev_grant_ref's ref field, as that's part of the public interface of the kernel and would require introducing a dependency on Xen's grant_table.h public header). Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/db7c38a5-0d75-d5d1-19de-e5fe9f0b9c48@suse.com Signed-off-by: Boris Ostrovsky

Xen/gntdev: correct error checking in gntdev_map_grant_pages()

2021-02-15T07:52:27+00:00

Failure of the kernel part of the mapping operation should also be indicated as an error to the caller, or else it may assume the respective kernel VA is okay to access. Furthermore gnttab_map_refs() failing still requires recording successfully mapped handles, so they can be unmapped subsequently. This in turn requires there to be a way to tell full hypercall failure from partial success - preset map_op status fields such that they won't "happen" to look as if the operation succeeded. Also again use GNTST_okay instead of implying its value (zero). This is part of XSA-361. Signed-off-by: Jan Beulich Cc: stable@vger.kernel.org Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

kernel/linux.git/include/xen/grant_table.h, branch v6.12.80

xen/grants: support allocating consecutive grants

xen: switch gnttab_end_foreign_access() to take a struct page pointer

xen: update grant_table.h

xen/grant-table: remove readonly parameter from functions

xen/grant-table: remove gnttab_*transfer*() functions

xen/gnttab: fix gnttab_end_foreign_access() without page specified

xen: remove gnttab_query_foreign_access()

xen/grant-table: add gnttab_try_end_foreign_access()

Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}

Xen/gntdev: correct error checking in gntdev_map_grant_pages()

xen/grant-table: remove gnttab_transfer() functions