From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Create a function to check the structure of short form symlink targets.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_shared.h | 1 +
fs/xfs/libxfs/xfs_symlink_remote.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 35 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index c6f4eb4..67ccb1a 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -143,5 +143,6 @@ bool xfs_symlink_hdr_ok(xfs_ino_t ino, uint32_t offset,
uint32_t size, struct xfs_buf *bp);
void xfs_symlink_local_to_remote(struct xfs_trans *tp, struct xfs_buf *bp,
struct xfs_inode *ip, struct xfs_ifork *ifp);
+xfs_failaddr_t xfs_symlink_shortform_verify(struct xfs_inode *ip);
#endif /* __XFS_SHARED_H__ */
diff --git a/fs/xfs/libxfs/xfs_symlink_remote.c b/fs/xfs/libxfs/xfs_symlink_remote.c
index 5497014..adf2d78 100644
--- a/fs/xfs/libxfs/xfs_symlink_remote.c
+++ b/fs/xfs/libxfs/xfs_symlink_remote.c
@@ -209,3 +209,37 @@ xfs_symlink_local_to_remote(
xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsymlink_hdr) +
ifp->if_bytes - 1);
}
+
+/* Verify the consistency of an inline symlink. */
+xfs_failaddr_t
+xfs_symlink_shortform_verify(
+ struct xfs_inode *ip)
+{
+ char *sfp;
+ char *endp;
+ struct xfs_ifork *ifp;
+ int size;
+
+ ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_LOCAL);
+ ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
+ sfp = (char *)ifp->if_u1.if_data;
+ size = ifp->if_bytes;
+ endp = sfp + size;
+
+ /* Zero length symlinks can exist while we're deleting a remote one. */
+ if (size == 0)
+ return NULL;
+
+ /* No negative sizes or overly long symlink targets. */
+ if (size < 0 || size > XFS_SYMLINK_MAXLEN)
+ return __this_address;
+
+ /* No NULLs in the target either. */
+ if (memchr(sfp, 0, size - 1))
+ return __this_address;
+
+ /* We /did/ null-terminate the buffer, right? */
+ if (*endp != 0)
+ return __this_address;
+ return NULL;
+}
--
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