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xfs: create structure verifier function for short form symlinks 

Create a function to check the structure of short form symlink targets.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Darrick J. Wong 2018-01-08 10:51:05 -08:00
parent 1e1bbd8e7e
commit 0795e004fd
2 changed files with 35 additions and 0 deletions
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1
fs/xfs/libxfs/xfs_shared.h
View File

@ -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__ */

34
fs/xfs/libxfs/xfs_symlink_remote.c
View File

@ -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;
}