[PATCH 05/10] parser: deal with headers entirely failing to parse
Stephen Finucane
stephen at that.guru
Thu Jun 29 06:12:41 AEST 2017
On Wed, 2017-06-28 at 17:48 +1000, Daniel Axtens wrote:
> It turns out that the attempts in clean_header() to convert
> headers to strings are not guaranteed to work: you can end up with,
> for example, a base64 decoding error which makes it impossible
> to determine any header content.
>
> In this case, sanitise_header() should return None, and thus
> clean_header() should return None. We then need to plumb that
> through.
>
> Signed-off-by: Daniel Axtens <dja at axtens.net>
I added 'strip' to 'clean_header' to simplify a lot of this. Other than that,
this looks good to me. Applied.
Reviewed-by: Stephen Finucane <stephen at that.guru>
> ---
> patchwork/parser.py | 70 +++++++++++++++++++++++++++++++++++++++++--------
> ----
> 1 file changed, 55 insertions(+), 15 deletions(-)
>
> diff --git a/patchwork/parser.py b/patchwork/parser.py
> index 032af8a7be7c..203e11584504 100644
> --- a/patchwork/parser.py
> +++ b/patchwork/parser.py
> @@ -23,6 +23,7 @@ from email.header import decode_header
> from email.header import make_header
> from email.utils import mktime_tz
> from email.utils import parsedate_tz
> +from email.errors import HeaderParseError
> from fnmatch import fnmatch
> import logging
> import re
> @@ -67,6 +68,13 @@ def sanitise_header(header_contents, header_name=None):
> then encode the result with make_header()
> """
>
> + try:
> + value = decode_header(header_contents)
> + except HeaderParseError:
> + # something has gone really wrong with header parsing.
> + # (e.g. base64 decoding) We probably can't recover, so:
> + return None
> +
> # We have some Py2/Py3 issues here.
> #
> # Firstly, the email parser (before we get here)
> @@ -85,7 +93,6 @@ def sanitise_header(header_contents, header_name=None):
> # We solve this by catching any Unicode errors, and then manually
> # handling any interesting headers.
>
> - value = decode_header(header_contents)
> try:
> header = make_header(value,
> header_name=header_name,
> @@ -130,6 +137,9 @@ def clean_header(header):
>
> sane_header = sanitise_header(header)
>
> + if sane_header is None:
> + return None
> +
> # on Py2, we want to do unicode(), on Py3, str().
> # That gets us the decoded, un-wrapped header.
> if six.PY2:
> @@ -157,9 +167,12 @@ def find_project_by_header(mail):
>
> for header in list_id_headers:
> if header in mail:
> + h = clean_header(mail.get(header))
> + if not h:
> + continue
>
> for listid_re in listid_res:
> - match = listid_re.match(clean_header(mail.get(header)))
> + match = listid_re.match(h)
> if match:
> break
>
> @@ -205,7 +218,11 @@ def _find_series_by_references(project, mail):
> Returns:
> The matching ``Series`` instance, if any
> """
> - for ref in [clean_header(mail.get('Message-Id'))] +
> find_references(mail):
> + refs = find_references(mail)
> + h = clean_header(mail.get('Message-Id'))
> + if h:
> + refs = [h] + refs
> + for ref in refs:
> try:
> return SeriesReference.objects.get(
> msgid=ref, series__project=project).series
> @@ -274,6 +291,10 @@ def find_series(project, mail):
>
> def find_author(mail):
> from_header = clean_header(mail.get('From'))
> +
> + if not from_header:
> + raise ValueError("Invalid 'From' header")
> +
> name, email = (None, None)
>
> # tuple of (regex, fn)
> @@ -320,7 +341,10 @@ def find_author(mail):
>
>
> def find_date(mail):
> - t = parsedate_tz(clean_header(mail.get('Date', '')))
> + h = clean_header(mail.get('Date', ''))
> + if not h:
> + return datetime.datetime.utcnow()
> + t = parsedate_tz(h)
> if not t:
> return datetime.datetime.utcnow()
> return datetime.datetime.utcfromtimestamp(mktime_tz(t))
> @@ -331,7 +355,7 @@ def find_headers(mail):
> for key, value in mail.items()]
>
> strings = [('%s: %s' % (key, header.encode()))
> - for (key, header) in headers]
> + for (key, header) in headers if header is not None]
>
> return '\n'.join(strings)
>
> @@ -347,11 +371,16 @@ def find_references(mail):
>
> if 'In-Reply-To' in mail:
> for in_reply_to in mail.get_all('In-Reply-To'):
> - refs.append(clean_header(in_reply_to).strip())
> + r = clean_header(in_reply_to)
> + if r:
> + refs.append(r.strip())
>
> if 'References' in mail:
> for references_header in mail.get_all('References'):
> - references = clean_header(references_header).split()
> + h = clean_header(references_header)
> + if not h:
> + continue
> + references = h.split()
> references.reverse()
> for ref in references:
> ref = ref.strip()
> @@ -573,6 +602,9 @@ def clean_subject(subject, drop_prefixes=None):
> prefix_re = re.compile(r'^\[([^\]]*)\]\s*(.*)$')
> subject = clean_header(subject)
>
> + if not subject:
> + raise ValueError("Invalid 'Subject' header")
> +
> if drop_prefixes is None:
> drop_prefixes = []
> else:
> @@ -610,7 +642,11 @@ def subject_check(subject):
> """Determine if a mail is a reply."""
> comment_re = re.compile(r'^(re)[:\s]\s*', re.I)
>
> - return comment_re.match(clean_header(subject))
> + h = clean_header(subject)
> + if not h:
> + return False
> +
> + return comment_re.match(h)
>
>
> def clean_content(content):
> @@ -790,10 +826,10 @@ def parse_pull_request(content):
>
> def find_state(mail):
> """Return the state with the given name or the default."""
> - state_name = clean_header(mail.get('X-Patchwork-State', '')).strip()
> + state_name = clean_header(mail.get('X-Patchwork-State', ''))
> if state_name:
> try:
> - return State.objects.get(name__iexact=state_name)
> + return State.objects.get(name__iexact=state_name.strip())
> except State.DoesNotExist:
> pass
> return get_default_initial_patch_state()
> @@ -827,10 +863,10 @@ def find_delegate_by_filename(project, filenames):
>
> def find_delegate_by_header(mail):
> """Return the delegate with the given email or None."""
> - delegate_email = clean_header(mail.get('X-Patchwork-Delegate',
> '')).strip()
> + delegate_email = clean_header(mail.get('X-Patchwork-Delegate', ''))
> if delegate_email:
> try:
> - return User.objects.get(email__iexact=delegate_email)
> + return User.objects.get(email__iexact=delegate_email.strip())
> except User.DoesNotExist:
> pass
> return None
> @@ -856,8 +892,8 @@ def parse_mail(mail, list_id=None):
> if 'Message-Id' not in mail:
> raise ValueError("Missing 'Message-Id' header")
>
> - hint = clean_header(mail.get('X-Patchwork-Hint', '')).lower()
> - if hint == 'ignore':
> + hint = clean_header(mail.get('X-Patchwork-Hint', ''))
> + if hint and hint.lower() == 'ignore':
> logger.debug("Ignoring email due to 'ignore' hint")
> return
>
> @@ -872,7 +908,11 @@ def parse_mail(mail, list_id=None):
>
> # parse metadata
>
> - msgid = clean_header(mail.get('Message-Id')).strip()
> + msgid = clean_header(mail.get('Message-Id'))
> + if not msgid:
> + raise ValueError("Broken 'Message-Id' header")
> + msgid = msgid.strip()
> +
> author = find_author(mail)
> subject = mail.get('Subject')
> name, prefixes = clean_subject(subject, [project.linkname])
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