[PATCH nft,v2] scanner: handle files with CRLF line terminators

[PATCH nft,v2] scanner: handle files with CRLF line terminators

[Pablo Neira Ayuso]

Extend scanner.l to deal with CRLF, otherwise -f fails to load:

 # file test.nft
 test.nft: ASCII text, with CRLF, LF line terminators
 # nft -f test.nft
 test.nft:1:13-13: Error: syntax error, unexpected junk
 table ip x {
             ^

Update full comment line to take CRLF too.

Add test to cover this usecase.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
v2: Update comment_line to accept CRLF.

 src/scanner.l                      |  6 ++++--
 tests/shell/testcases/nft-f/crlf_0 | 17 +++++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100755 tests/shell/testcases/nft-f/crlf_0

diff --git a/src/scanner.l b/src/scanner.l
index e72a427aab48..254a23fb4068 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -113,7 +113,9 @@ extern void	yyset_column(int, yyscan_t);
 
 space		[ ]
 tab		\t
-newline		\n
+newline_lf	\n
+newline_crlf	\r\n
+newline		({newline_lf}|{newline_crlf})
 digit		[0-9]
 hexdigit	[0-9a-fA-F]
 decstring	{digit}+
@@ -124,7 +126,7 @@ string		({letter}|[_.])({letter}|{digit}|[/\-_\.])*
 quotedstring	\"[^"]*\"
 asteriskstring	({string}\*|{string}\\\*|\\\*|{string}\\\*{string})
 comment		#.*$
-comment_line	^[ \t]*#.*\n
+comment_line	^[ \t]*#.*(\r\n|\n)
 slash		\/
 
 timestring	([0-9]+d)?([0-9]+h)?([0-9]+m)?([0-9]+s)?([0-9]+ms)?
diff --git a/tests/shell/testcases/nft-f/crlf_0 b/tests/shell/testcases/nft-f/crlf_0
new file mode 100755
index 000000000000..7ba785c8656a
--- /dev/null
+++ b/tests/shell/testcases/nft-f/crlf_0
@@ -0,0 +1,17 @@
+#!/bin/bash
+
+set -e
+
+RULESET="table ip foo {\r\n\tchain ber {\r\n\t}\r\n}"
+
+tmpfile=$(mktemp)
+if [ ! -w $tmpfile ] ; then
+        echo "Failed to create tmp file" >&2
+        exit 0
+fi
+
+trap "rm -rf $tmpfile" EXIT # cleanup if aborted
+
+echo -e "$RULESET" > $tmpfile
+
+$NFT -f "$tmpfile"
-- 
2.30.2

Re: [PATCH nft,v2] scanner: handle files with CRLF line terminators

[Pablo Neira Ayuso]

On Thu, Dec 08, 2022 at 02:41:51AM +0100, Pablo Neira Ayuso wrote:
> Extend scanner.l to deal with CRLF, otherwise -f fails to load:
> 
>  # file test.nft
>  test.nft: ASCII text, with CRLF, LF line terminators
>  # nft -f test.nft
>  test.nft:1:13-13: Error: syntax error, unexpected junk
>  table ip x {
>              ^
> 
> Update full comment line to take CRLF too.
> 
> Add test to cover this usecase.

I am considering to keep back this patch. At quick glance, other
existing userspace tooling in Linux do not support for CRLF files.

I might follow up with a different approach: provide a more meaningful
error message, instead of saying "unexpected junk", report to the
users that the file contains CRLF and that needs to be fixed.