ssh patch that originated from OpenSSH 7.5p1 update

[emaste]

Summary

Came from R10:d93a896ef95946b0bf1219866fcb324b78543444

[emaste]

While updating in-tree OpenSSH to 8.3p1 I came across this patch snippet, which originated in the referenced commit; this code has no other FreeBSD-specific changes prior to this.

[emaste]

I'm not sure of the reason for this change; there were no upstream changes in session.c between 7.4p1 and 7.5p1.

While pondering the leak introduced by the change I found that Coverity identified it (CID 1379281).

[emaste]

Oh,

Note that with all functions in this group, you should not call free(3)
on any pointers returned.  Memory allocated during retrieval or
processing of capability tags is automatically reused by subsequent calls
to functions in this group, or deallocated on calling login_close().

[emaste]

http://lists.mindrot.org/pipermail/openssh-unix-dev/2021-February/039129.html

[emaste]

session.c

1278–1279

in base system now we've kept the const char *nl; but following upstream have dropped the free()