On Mon, Jun 15, 2015 at 05:13:50PM -0500, Eric Sandeen wrote: > If we create a CRC filesystem, mount it, and create a symlink with > a path long enough that it can't live in the inode, we get a very > strange result upon remount: > > # ls -l mnt > total 4 > lrwxrwxrwx. 1 root root 929 Jun 15 16:58 link -> XSLM > > XSLM is the V5 symlink block header magic (which happens to be > followed by a NUL, so the string looks terminated). > > xfs_readlink_bmap() advanced cur_chunk by the size of the header > for CRC filesystems, but never actually used that pointer; it > kept reading from bp->b_addr, which is the start of the block, > rather than the start of the symlink data after the header. > > Looks like this problem goes back to v3.10. > > Fixing this gets us reading the proper link target, again. > > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > --- > > diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c > index 3df411e..40c0765 100644 > --- a/fs/xfs/xfs_symlink.c > +++ b/fs/xfs/xfs_symlink.c > @@ -104,7 +104,7 @@ xfs_readlink_bmap( > cur_chunk += sizeof(struct xfs_dsymlink_hdr); > } > > - memcpy(link + offset, bp->b_addr, byte_cnt); > + memcpy(link + offset, cur_chunk, byte_cnt); > > pathlen -= byte_cnt; > offset += byte_cnt; Looks like the correct fix, so: Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx> However, it raises a more disturbing question: how did we not trip over this until now? I though we had long symlink test coverage in xfstests but clearly we haven't - do you have a test that closes this verification hole? Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
