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putty-source/utils/antispoof.c
Simon Tatham be8d3974ff Generalise strbuf_catf() into put_fmt().
marshal.h now provides a macro put_fmt() which allows you to write
arbitrary printf-formatted data to an arbitrary BinarySink.

We already had this facility for strbufs in particular, in the form of
strbuf_catf(). That was able to take advantage of knowing the inner
structure of a strbuf to minimise memory allocation (it would snprintf
directly into the strbuf's existing buffer if possible). For a general
black-box BinarySink we can't do that, so instead we dupvprintf into a
temporary buffer.

For consistency, I've removed strbuf_catf, and converted all uses of
it into the new put_fmt - and I've also added an extra vtable method
in the BinarySink API, so that put_fmt can still use strbuf_catf's
more efficient memory management when talking to a strbuf, and fall
back to the simpler strategy when that's not available.
2021-11-19 11:32:47 +00:00

29 lines
907 B
C

#include "putty.h"
#include "misc.h"
void seat_antispoof_msg(InteractionReadySeat iseat, const char *msg)
{
strbuf *sb = strbuf_new();
seat_set_trust_status(iseat.seat, true);
if (seat_can_set_trust_status(iseat.seat)) {
/*
* If the seat can directly indicate that this message is
* generated by the client, then we can just use the message
* unmodified as an unspoofable header.
*/
put_datapl(sb, ptrlen_from_asciz(msg));
} else if (*msg) {
/*
* Otherwise, add enough padding around it that the server
* wouldn't be able to mimic it within our line-length
* constraint.
*/
put_fmt(sb, "-- %s ", msg);
while (sb->len < 78)
put_byte(sb, '-');
}
put_datapl(sb, PTRLEN_LITERAL("\r\n"));
seat_banner_pl(iseat, ptrlen_from_strbuf(sb));
strbuf_free(sb);
}