Re: [libvirt] [PATCH] Strip control codes in virBufferEscapeString
On Mon, Mar 30, 2015 at 07:06:45AM -0600, Eric Blake wrote:
On 03/30/2015 05:02 AM, Ján Tomko wrote:
> These cannot be represented in XML.
Yes they can, via entities. DV would know for sure, but I think that
 is the entity for the C byte '\1'.
Only in XML 1.1.
For XML 1.0: http://www.w3.org/TR/xml/#dt-charref
Well-formedness constraint: Legal Character
Characters referred to using character references MUST match the
production for Char.
Which is: http://www.w3.org/TR/xml/#NT-Char
[2] Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] |
[#xE000-#xFFFD] | [#x10000-#x10FFFF] /* any Unicode character,
excluding the surrogate blocks, FFFE, and FFFF. */
Both libvirt and virt-xml-validate choke on those entities
error: (domain_definition):2: xmlParseCharRef: invalid xmlChar value 1
<name>f21</name>
DV was the one who wrote the code to skip over control characters in
commit b36f453a581f27a4a43558978724a52df32045bb (v0.3.0~1)
new function virBufferEscapeString() to format a string while
escaping its content for XML, and apply it to a couple of
obvious places, should fix bug #206653
It was the optimization in
commit 0af02cb2e8d8192958735880e135ab69beb437c5 (v0.8.6~57)
buf: Simplify virBufferEscapeString
which broke this for strings that do have control codes,
but not escapable characters.
>
> We have been stripping them, but only if the string had
> characters that needed escaping: <>"'&
>
> Extend the strcspn check to include control codes, and strip
> them even if we don't do any escaping.
NACK. Stripping control codes from a volume name represents the wrong
name. We need to escape the problematic bytes, rather than strip them.
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1184131
> https://bugzilla.redhat.com/show_bug.cgi?id=1066564
> ---
> src/util/virbuffer.c | 14 +++++++++++---
> tests/virbuftest.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 60 insertions(+), 3 deletions(-)
As there are real bugs that will be fixed once we use the correct
entities, I'm looking forward to v2.
This fixes the real bug of libvirt generating unparsable XML, which breaks
creation of any VMs in virt-manager.
Jan
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