From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Create a function to perform structure verification for short form
extended attributes.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_attr_leaf.c | 74 +++++++++++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_attr_leaf.h | 1 +
2 files changed, 75 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 68c66fa..ae3bccb 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -872,6 +872,80 @@ xfs_attr_shortform_allfit(
return xfs_attr_shortform_bytesfit(dp, bytes);
}
+/* Verify the consistency of an inline attribute fork. */
+xfs_failaddr_t
+xfs_attr_shortform_verify(
+ struct xfs_inode *ip)
+{
+ struct xfs_attr_shortform *sfp;
+ struct xfs_attr_sf_entry *sfep;
+ struct xfs_attr_sf_entry *next_sfep;
+ char *endp;
+ struct xfs_ifork *ifp;
+ int i;
+ int size;
+
+ ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_LOCAL);
+ ifp = XFS_IFORK_PTR(ip, XFS_ATTR_FORK);
+ sfp = (struct xfs_attr_shortform *)ifp->if_u1.if_data;
+ size = ifp->if_bytes;
+
+ /*
+ * Give up if the attribute is way too short.
+ */
+ if (size < sizeof(struct xfs_attr_sf_hdr))
+ return __this_address;
+
+ endp = (char *)sfp + size;
+
+ /* Check all reported entries */
+ sfep = &sfp->list[0];
+ for (i = 0; i < sfp->hdr.count; i++) {
+ /*
+ * struct xfs_attr_sf_entry has a variable length.
+ * Check the fixed-offset parts of the structure are
+ * within the data buffer.
+ */
+ if (((char *)sfep + sizeof(*sfep)) >= endp)
+ return __this_address;
+
+ /* Don't allow names with known bad length. */
+ if (sfep->namelen == 0)
+ return __this_address;
+
+ /*
+ * Check that the variable-length part of the structure is
+ * within the data buffer. The next entry starts after the
+ * name component, so nextentry is an acceptable test.
+ */
+ next_sfep = XFS_ATTR_SF_NEXTENTRY(sfep);
+ if ((char *)next_sfep > endp)
+ return __this_address;
+
+ /*
+ * Check for unknown flags. Short form doesn't support
+ * the incomplete or local bits, so we can use the namespace
+ * mask here.
+ */
+ if (sfep->flags & ~XFS_ATTR_NSP_ONDISK_MASK)
+ return __this_address;
+
+ /*
+ * Check for invalid namespace combinations. We only allow
+ * one namespace flag per xattr, so we can just count the
+ * bits (i.e. hweight) here.
+ */
+ if (hweight8(sfep->flags & XFS_ATTR_NSP_ONDISK_MASK) > 1)
+ return __this_address;
+
+ sfep = next_sfep;
+ }
+ if ((void *)sfep != (void *)endp)
+ return __this_address;
+
+ return NULL;
+}
+
/*
* Convert a leaf attribute list to shortform attribute list
*/
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.h b/fs/xfs/libxfs/xfs_attr_leaf.h
index 894124e..4da08af 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.h
+++ b/fs/xfs/libxfs/xfs_attr_leaf.h
@@ -53,6 +53,7 @@ int xfs_attr_shortform_to_leaf(struct xfs_da_args *args,
int xfs_attr_shortform_remove(struct xfs_da_args *args);
int xfs_attr_shortform_allfit(struct xfs_buf *bp, struct xfs_inode *dp);
int xfs_attr_shortform_bytesfit(struct xfs_inode *dp, int bytes);
+xfs_failaddr_t xfs_attr_shortform_verify(struct xfs_inode *ip);
void xfs_attr_fork_remove(struct xfs_inode *ip, struct xfs_trans *tp);
/*
--
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