diff options
| -rw-r--r-- | networking/udhcp/dhcpc.c | 50 |
1 files changed, 23 insertions, 27 deletions
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c index d1e40ee65..d9269f277 100644 --- a/networking/udhcp/dhcpc.c +++ b/networking/udhcp/dhcpc.c @@ -161,8 +161,8 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ int len, type, optlen; char *dest, *ret; - /* option points to OPT_DATA, need to go back and get OPT_LEN */ - len = option[OPT_LEN - OPT_DATA]; + /* option points to OPT_DATA, need to go back to get OPT_LEN */ + len = option[-OPT_DATA + OPT_LEN]; type = optflag->flags & OPTION_TYPE_MASK; optlen = dhcp_option_lengths[type]; @@ -252,39 +252,29 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ return ret; } - case OPTION_6RD: { + case OPTION_6RD: /* Option binary format (see RFC 5969): - * 0 1 2 3 - * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + * 0 1 2 3 + * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | | * | 6rdPrefix | - * | (16 octets) | - * | | - * | | - * | | + * ... (16 octets) ... * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * | 6rdBRIPv4Address(es) | - * . . - * . . - * . . + * ... 6rdBRIPv4Address(es) ... * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - * * We convert it to a string * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..." - */ - - /* Sanity check: ensure that our length is at least 22 bytes, that + * + * Sanity check: ensure that our length is at least 22 bytes, that * IPv4MaskLen <= 32, * 6rdPrefixLen <= 128, * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128 * (2nd condition need no check - it follows from 1st and 3rd). - * If any of these requirements is not fulfilled, return with empty - * value. + * Else, return envvar with empty value ("optname=") */ - if (len >= 22 + if (len >= (1 + 1 + 16 + 4) && option[0] <= 32 && (option[1] + 32 - option[0]) <= 128 ) { @@ -295,19 +285,20 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ /* 6rdPrefix */ dest += sprint_nip6(dest, /* "", */ option); option += 16; - len -= 1 + 1 + 16; - /* 6rdBRIPv4Address(es) */ + len -= 1 + 1 + 16 + 4; + /* "+ 4" above corresponds to the length of IPv4 addr + * we consume in the loop below */ while (1) { + /* 6rdBRIPv4Address(es) */ dest += sprint_nip(dest, " ", option); option += 4; - len -= 4; + len -= 4; /* do we have yet another 4+ bytes? */ if (len < 0) - break; + break; /* no */ } } return ret; - } #if ENABLE_FEATURE_UDHCP_RFC3397 case OPTION_DNS_STRING: /* unpack option into dest; use ret for prefix (i.e., "optname=") */ @@ -347,6 +338,10 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ return ret; #endif } /* switch */ + + /* If we are here, try to format any remaining data + * in the option as another, similarly-formatted option + */ option += optlen; len -= optlen; // TODO: it can be a list only if (optflag->flags & OPTION_LIST). @@ -356,7 +351,8 @@ static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_ break; *dest++ = ' '; *dest = '\0'; - } + } /* while */ + return ret; } |