From 29fbba7b6d967bedc646a84877bb617f04d14c43 Mon Sep 17 00:00:00 2001 From: Michael Forney Date: Mon, 8 Feb 2021 20:59:01 -0800 Subject: [PATCH] [9front] upas/vf: exclude mime boundary from temporary attachment files validateattachment has no business with the mime boundary; it is not part of the attachment itself. Also, it causes the boundary to be dropped in the message output from upas/vf, effectively dropping the following attachment (though the content is still present after the last boundary of the wrapped first attachment part). Consider the following sequence of events: 1. upas/vf is run on a message containing two attachments. 2. The first attachment does not have a known extension, so is saved to a temporary file *including* the following mime boundary. 3. This file is opened as p->tmpbuf, which is used for subsequent reads until switching back to stdin. 4. The attachment fails validateattachment, so upas/vf wraps it in a multipart with a warning message. 5. problemchild() calls passbody(p, 0), which copies from p->tmpbuf until it hits the outer boundary line, which it excludes, seeks back one line, then returns the outer multipart. 6. problemchild() then writes its own boundary, and then copies one line from *stdin* to stdout, expecting the outer boundary. However, this boundary was already read from stdin in 2, so it ends up reading the first line of the subsequent part instead. To fix this, pass 0 to passbody() in save() to exclude it from the attachment file and make it available in stdin when expected. --- sys/src/cmd/upas/vf/vf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/src/cmd/upas/vf/vf.c b/sys/src/cmd/upas/vf/vf.c index d527dc7b2..60342d247 100644 --- a/sys/src/cmd/upas/vf/vf.c +++ b/sys/src/cmd/upas/vf/vf.c @@ -387,7 +387,7 @@ save(Part *p, char *file) Bprint(&out, "From virusfilter %τ\n", thedate(&tm)); writeheader(p, 0); bodyoff = Boffset(&out); - passbody(p, 1); + passbody(p, 0); Bprint(&out, "\n"); Bterm(&out); close(fd);