GitHub user bgaff opened a pull request:
https://github.com/apache/trafficserver/pull/300
TS-3956: Header_rewrite applies strange logic with = operator
Please see ticket TS-3956 for more information, I'm using github here so
that @zwoop / @jacksontj can provide a code review.
It appears that whitespace causes weird behavior with header_rewrite, for
example:
If you remove the white space before the = and the quotes it appears to
behave correctly. This whitespace issue is likely to cause strange bugs and
needs to be fixed.
```
cond %{READ_REQUEST_HDR_HOOK}
cond %{CLIENT-HEADER:Host} /^localhost$/ [AND]
cond %{CLIENT-HEADER:non_existent_header} = "shouldnt_exist_anyway" [AND]
add-header X-HeaderRewriteApplied true
```
With the following request:
```
curl -v localhost/
```
Header_rewrite will incorrectly apply the rule:
```
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Building resources, hook=TS_HTTP_READ_REQUEST_HDR_HOOK
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Adding TXN client request header buffers
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Getting Header: Host, field_loc: 0x7fffd02070d0
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Appending HEADER(Host) to evaluation value -> localhost
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite) Test
regular expression ^localhost$ : localhost
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Successfully found regular expression match
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Evaluating HEADER(): localhost - rval: 1
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Getting Header: non_existent_header, field_loc: (nil)
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Evaluating HEADER(): - rval: 1
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
OperatorAddHeader::exec() invoked on header X-HeaderRewriteApplied: true
[Oct 4 20:56:49.245] Server {0x7ffff61b5700} DIAG: (header_rewrite)
Adding header X-HeaderRewriteApplied
```
I have a proposed patch incoming it maintains backwards compatability while
being a little more flexible with whitespace, for example the following config
will parse as:
```
cond %{READ_REQUEST_HDR_HOOK}
cond %{CLIENT-HEADER:Host} /^localhost$/ [AND]
cond %{CLIENT-HEADER:Host} =a
# COMMENT!
# COMMENT
cond %{Client-HEADER:Foo} =b
cond %{Client-HEADER:Blah} = x
cond %{CLIENT-HEADER:non_existent_header} = "shouldnt_ exist _anyway"
[AND]
cond %{CLIENT-HEADER:non_existent_header} = "shouldnt_ = _anyway"
[AND]
cond %{CLIENT-HEADER:non_existent_header} ="=" [AND]
cond %{CLIENT-HEADER:non_existent_header} ="" [AND]
add-header X-HeaderRewriteApplied true
```
```
$1 = std::vector of length 2, capacity 2 = {"cond",
"%{READ_REQUEST_HDR_HOOK}"}
$2 = std::vector of length 4, capacity 4 = {"cond",
"%{CLIENT-HEADER:Host}", "/^localhost$/", "[AND]"}
$3 = std::vector of length 4, capacity 4 = {"cond",
"%{CLIENT-HEADER:Host}", "=", "a"}
$4 = std::vector of length 4, capacity 4 = {"cond", "%{Client-HEADER:Foo}",
"=", "b"}
$5 = std::vector of length 4, capacity 4 = {"cond",
"%{Client-HEADER:Blah}", "=", "x"}
$6 = std::vector of length 5, capacity 8 = {"cond",
"%{CLIENT-HEADER:non_existent_header}", "=", "shouldnt_ exist _anyway",
"[AND]"}
$7 = std::vector of length 5, capacity 8 = {"cond",
"%{CLIENT-HEADER:non_existent_header}", "=", "shouldnt_ = _anyway",
"[AND]"}
$8 = std::vector of length 5, capacity 8 = {"cond",
"%{CLIENT-HEADER:non_existent_header}", "=", "=", "[AND]"}
$9 = std::vector of length 5, capacity 8 = {"cond",
"%{CLIENT-HEADER:non_existent_header}", "=", "", "[AND]"}
$10 = std::vector of length 3, capacity 4 = {"add-header",
"X-HeaderRewriteApplied", "true"}
```
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/bgaff/trafficserver master
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/trafficserver/pull/300.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #300
----
commit bd3f2a8a3da46b0a4c59c5cb1a2509be9b02c0dd
Author: Brian Geffon <bri...@apache.org>
Date: 2015-10-05T07:23:45Z
TS-3956: Header_rewrite applies strange logic with = operator and whitespace
----
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
