On Tue, Feb 18, 2025 at 09:52:31AM +0100, Stefano Brivio wrote:
Otherwise we'll limit messages to 577 bytes,
instead of 576 bytes as
intended:
$
fqdn="thirtytwocharactersforeachlabel.thirtytwocharactersforeachlabel.thirtytwocharactersforeachlabel.thirtytwocharactersforeachlabel.thirtytwocharactersforeachlabel.thirtytwocharactersforeachlabel.thirtytwocharactersforeachlabel.then_make_it_251_with_this"
$ hostname="__eighteen_bytes__"
$ ./pasta --fqdn ${fqdn} -H ${hostname} -p dhcp.pcap -- /sbin/dhclient -4
Saving packet capture to dhcp.pcap
$ tshark -r dhcp.pcap -V -Y 'dhcp.option.value == 5' | grep "Total
Length"
Total Length: 577
This was hidden by the issue fixed by commit bcc4908c2b4a ("dhcp
Remove option 255 length byte") until now.
Fixes: 31e8109a86ee ("dhcp, dhcpv6: Add hostname and client fqdn ops")
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>
---
dhcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/dhcp.c b/dhcp.c
index 4a209f1..b7d5ea3 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -143,7 +143,7 @@ static bool fill_one(struct msg *m, int o, int *offset)
size_t slen = opts[o].slen;
/* If we don't have space to write the option, then just skip */
- if (*offset + 1 /* length of option */ + slen > OPT_MAX)
+ if (*offset + 2 /* code and length of option */ + slen > OPT_MAX)
return true;
m->o[*offset] = o;
--
David Gibson (he or they) | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you, not the other way
| around.
http://www.ozlabs.org/~dgibson