[Asterisk-code-review] chan sip: Do not allow non-SP/HTAB between header key and co... (asterisk[11])

[Mark Michelson]

Mark Michelson has uploaded a new patch set (#2). ( https://gerrit.asterisk.org/4582 )

Change subject: chan_sip: Do not allow non-SP/HTAB between header key and colon.
......................................................................

chan_sip: Do not allow non-SP/HTAB between header key and colon.

RFC says SIP headers look like:

    HCOLON  =  *( SP / HTAB ) ":" SWS
    SWS     =  [LWS]                    ; sep whitespace
    LWS     =  [*WSP CRLF] 1*WSP        ; linear whitespace
    WSP     =  SP / HTAB                ; from rfc2234

chan_sip implemented this:

    HCOLON  =  *( LOWCTL / SP ) ":" SWS
    LOWCTL  = %x00-1F                   ; CTL without DEL

This discrepancy meant that SIP proxies in front of Asterisk with
chan_sip could pass on unknown headers with \x00-\x1F in them, which
would be treated by Asterisk as a different (known) header.  For
example, the "To\x01:" header would gladly be forwarded by some proxies
as irrelevant, but chan_sip would treat it as the relevant "To:" header.

Those relying on a SIP proxy to scrub certain headers could mistakenly
get unexpected and unvalidated data fed to Asterisk.

This change fixes so chan_sip only considers SP/HTAB as valid tokens
before the colon, making it agree on the headers with other speakers of
SIP.

ASTERISK-26433 #close
AST-2016-009

Change-Id: I78086fbc524ac733b8f7f78cb423c91075fd489b
---
M channels/chan_sip.c
1 file changed, 3 insertions(+), 5 deletions(-)


  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/82/4582/2
-- 
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I78086fbc524ac733b8f7f78cb423c91075fd489b
Gerrit-PatchSet: 2
Gerrit-Project: asterisk
Gerrit-Branch: 11
Gerrit-Owner: Mark Michelson <mmichelson at digium.com>