Hi Alan,
2014-10-20 15:26, Carew, Alan:
> A comment on my own patch.
>
> Making the size of result_buf consistent across each OS and keeping it as
> large
> as the Linux BUFSIZ(8192) doesn't really address the core issue.
>
> In the event that a user of librte_cmdline creates a custom context with a
> result structure > 8192 bytes then this problem will occur again, though
> somewhat unlikely, as the minimum number of the largest type would be 64 x
> cmdline_fixed_string_t types within a result structure, at its current size.
>
> There is no checking of overflow, I would be tempted to add a runtime check in
> cmdline_parse()/match_inst(), however I would be more comfortable with a build
> time check for this type of problem.
>
> Due to the opaque handling of user defined contexts there is no obvious way to
> do this at build time.
>
> Thoughts?
librte_cmdline derivates from libcmdline written by Olivier Matz:
http://git.droids-corp.org/?p=libcmdline.git
Maybe there are some fixes to take here, and probably Olivier will have
some good insights.
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Alan Carew
> > Sent: Monday, October 20, 2014 4:23 PM
> > To: dev at dpdk.org
> > Subject: [dpdk-dev] [PATCH] librte_cmdline: FreeBSD Fix oveflow when size of
> > command result structure is greater than BUFSIZ
> >
> > When using test-pmd with flow director in FreeBSD, the application will
> > segfault/Bus error while parsing the command-line. This is due to how
> > each commands result structure is represented during parsing, where the
> > offsets
> > for each tokens value is stored in a character array(char
> > result_buf[BUFSIZ])
> > in cmdline_parse()(./lib/librte_cmdline/cmdline_parse.c).
> >
> > The overflow occurs where BUFSIZ is less than the size of a commands result
> > structure, in this case "struct cmd_pkt_filter_result"
> > (app/test-pmd/cmdline.c) is 1088 bytes and BUFSIZ on FreeBSD is 1024 bytes
> > as
> > opposed to 8192 bytes on Linux.
> >
> > This patch removes the OS dependency on BUFSIZ and defines and uses a
> > library #define CMDLINE_PARSE_RESULT_BUFSIZE 8192
> >
> > The problem can be reproduced by running test-pmd on FreeBSD:
> > ./testpmd -c 0x3 -n 4 -- -i --portmask=0x3 --pkt-filter-mode=perfect
> > And adding a filter:
> > add_perfect_filter 0 udp src 192.168.0.0 1024 dst 192.168.0.0 1024 flexbytes
> > 0x800 vlan 0 queue 0 soft 0x17
> >
> > Signed-off-by: Alan Carew <alan.carew at intel.com>
> > ---
> > lib/librte_cmdline/cmdline_parse.c | 2 +-
> > lib/librte_cmdline/cmdline_parse.h | 3 +++
> > 2 files changed, 4 insertions(+), 1 deletion(-)
[...]
> > --- a/lib/librte_cmdline/cmdline_parse.c
> > +++ b/lib/librte_cmdline/cmdline_parse.c
> > @@ -219,7 +219,7 @@ cmdline_parse(struct cmdline *cl, const char * buf)
> > unsigned int inst_num=0;
> > cmdline_parse_inst_t *inst;
> > const char *curbuf;
> > - char result_buf[BUFSIZ];
> > + char result_buf[CMDLINE_PARSE_RESULT_BUFSIZE];
[...]
> > --- a/lib/librte_cmdline/cmdline_parse.h
> > +++ b/lib/librte_cmdline/cmdline_parse.h
> > @@ -80,6 +80,9 @@ extern "C" {
> > #define CMDLINE_PARSE_COMPLETE_AGAIN 1
> > #define CMDLINE_PARSE_COMPLETED_BUFFER 2
> >
> > +/* maximum buffer size for parsed result */
> > +#define CMDLINE_PARSE_RESULT_BUFSIZE 8192
> > +
