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53 lines
2.0 KiB
53 lines
2.0 KiB
From: Andreas Gruenbacher <agruen@suse.de>
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Date: Mon, 14 Jun 2010 09:22:14 +0530
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Subject: [PATCH 13/16] richacl: Restrict access check algorithm
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Patch-mainline: not yet
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We want to avoid applying the file masks to an acl when changing the
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file permission bits or performing an access check. On the other hand,
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when we *do* apply the file masks to the acl, we want the resulting acl
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to produce the same access check results with the standard nfs4 access
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check algorithm as the richacl access check algorithm with the original
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acl. This is already the case, except in the following scenario:
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With file masks equivalent to file mode 0600, the following acl would
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grant the owner rw access if the owner is in the owning group:
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group@:rw::allow
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There is no way to express this in an nfs4 acl; the result is always a
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more restrictive acl. There are two approaches to deal with this
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difference: either accept that it exists and that applying the file
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masks is imperfect, or change the richacl access check algorithm so that
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such accesses are denied.
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This patch denies such accesses and makes sure that the richacl access
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check algorithm grants the same accesses as the nfsv4 acl with the file
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masks applied.
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Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
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Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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---
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fs/richacl_base.c | 10 ++++++++++
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1 file changed, 10 insertions(+)
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--- a/fs/richacl_base.c
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+++ b/fs/richacl_base.c
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@@ -423,6 +423,16 @@ richacl_permission(struct inode *inode,
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} else
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goto is_everyone;
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+ /*
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+ * Apply the group file mask to entries other than OWNER@ and
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+ * EVERYONE@. This is not required for correct access checking
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+ * but ensures that we grant the same permissions as the acl
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+ * computed by richacl_apply_masks() would grant. See
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+ * richacl_apply_masks() for a more detailed explanation.
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+ */
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+ if (richace_is_allow(ace))
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+ ace_mask &= acl->a_group_mask;
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+
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is_owner:
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/* The process is in the owner or group file class. */
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in_owner_or_group_class = 1;
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