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authorDenys Vlasenko <vda.linux@googlemail.com>2011-10-20 10:29:18 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2011-10-20 10:29:18 (GMT)
commit1dff672335ce227c0875864e3819c8464f978c08 (patch)
treeb66d7fcbaa345ffbadccee19d7af0809bc96d5a5
parent42816c204d2c592a86498c3d3b215c9b4d80e9e1 (diff)
downloadbusybox-1dff672335ce227c0875864e3819c8464f978c08.tar.gz
busybox-1dff672335ce227c0875864e3819c8464f978c08.tar.bz2
udhcpc: fix 6rd option formatting (was using 4 more bytes than there is)
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/udhcp/dhcpc.c50
1 files changed, 23 insertions, 27 deletions
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index d1e40ee..d9269f2 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;
}