diff options
Diffstat (limited to 'pxelinux.asm')
| -rw-r--r-- | pxelinux.asm | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/pxelinux.asm b/pxelinux.asm index d0f82771..ba9c6e19 100644 --- a/pxelinux.asm +++ b/pxelinux.asm @@ -2099,6 +2099,27 @@ pxe_get_cached_info: jmp kaboom ; +; ip_ok +; +; Tests an IP address in EAX for validity; return with ZF=1 for bad. +; We used to refuse class E, but class E addresses are likely to become +; assignable unicast addresses in the near future. +; +ip_ok: + push ax + cmp eax,-1 ; Refuse the all-ones address + jz .out + and al,al ; Refuse network zero + jz .out + cmp al,127 ; Refuse loopback + jz .out + and al,0F0h + cmp al,224 ; Refuse class D +.out: + pop ax + ret + +; ; parse_dhcp ; ; Parse a DHCP packet. This includes dealing with "overloaded" @@ -2123,17 +2144,14 @@ pxe_get_cached_info: parse_dhcp: mov byte [OverLoad],0 ; Assume no overload mov eax, [trackbuf+bootp.yip] - and eax, eax + call ip_ok jz .noyip - cmp al,224 ; Class D or higher -> bad - jae .noyip mov [MyIP], eax .noyip: mov eax, [trackbuf+bootp.sip] and eax, eax + call ip_ok jz .nosip - cmp al,224 ; Class D or higher -> bad - jae .nosip mov [ServerIP], eax .nosip: sub cx, bootp.options @@ -2288,8 +2306,8 @@ dopt_%2: mov eax,[si] cmp dword [ServerIP],0 jne .skip ; Already have a next server IP - cmp al,224 ; Class D or higher - jae .skip + call ip_ok + jz .skip mov [ServerIP],eax .skip: ret |