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udhcp: dname_dec may return NULL, account for that case

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Other random cleanips included...

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-07-03 16:59:59 +02:00
parent c3b6f2c7e1
commit 7895b91743
5 changed files with 66 additions and 58 deletions
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4
networking/udhcp/clientpacket.c
View File

@ -166,7 +166,7 @@ int FAST_FUNC send_select(uint32_t xid, uint32_t server, uint32_t requested)
}
/* Unicasts or broadcasts a DHCP renew message */
/* Unicast or broadcast a DHCP renew message */
int FAST_FUNC send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
{
struct dhcp_packet packet;
@ -186,7 +186,7 @@ int FAST_FUNC send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
}
/* Unicasts a DHCP release message */
/* Unicast a DHCP release message */
int FAST_FUNC send_release(uint32_t server, uint32_t ciaddr)
{
struct dhcp_packet packet;

65
networking/udhcp/domain_codec.c
View File

@ -25,16 +25,9 @@
*/
char* FAST_FUNC dname_dec(const uint8_t *cstr, int clen, const char *pre)
{
const uint8_t *c;
int crtpos, retpos, depth, plen = 0, len = 0;
char *ret = ret; /* for compiler */
char *dst = NULL;
if (!cstr)
return NULL;
if (pre)
plen = strlen(pre);
/* We make two passes over the cstr string. First, we compute
* how long the resulting string would be. Then we allocate a
* new buffer of the required length, and fill it in with the
@ -42,59 +35,71 @@ char* FAST_FUNC dname_dec(const uint8_t *cstr, int clen, const char *pre)
* having to deal with requiring callers to supply their own
* buffer, then having to check if it's sufficiently large, etc.
*/
while (!dst) {
if (len > 0) { /* second pass? allocate dst buffer and copy pre */
dst = xmalloc(len + plen);
memcpy(dst, pre, plen);
}
while (1) {
/* note: "return NULL" below are leak-safe since
* dst isn't yet allocated */
const uint8_t *c;
unsigned crtpos, retpos, depth, len;
crtpos = retpos = depth = len = 0;
while (crtpos < clen) {
c = cstr + crtpos;
if ((*c & NS_CMPRSFLGS) != 0) { /* pointer */
if (*c & NS_CMPRSFLGS) {
/* pointer */
if (crtpos + 2 > clen) /* no offset to jump to? abort */
return NULL;
if (retpos == 0) /* toplevel? save return spot */
retpos = crtpos + 2;
depth++;
crtpos = ((*c & 0x3f) << 8) | (*(c + 1) & 0xff); /* jump */
} else if (*c) { /* label */
crtpos = ((c[0] & 0x3f) << 8) | (c[1] & 0xff); /* jump */
} else if (*c) {
/* label */
if (crtpos + *c + 1 > clen) /* label too long? abort */
return NULL;
if (dst)
memcpy(dst + plen + len, c + 1, *c);
memcpy(dst + len, c + 1, *c);
len += *c + 1;
crtpos += *c + 1;
if (dst)
*(dst + plen + len - 1) = '.';
} else { /* null: end of current domain name */
if (retpos == 0) { /* toplevel? keep going */
dst[len - 1] = '.';
} else {
/* null: end of current domain name */
if (retpos == 0) {
/* toplevel? keep going */
crtpos++;
} else { /* return to toplevel saved spot */
} else {
/* return to toplevel saved spot */
crtpos = retpos;
retpos = depth = 0;
}
if (dst)
*(dst + plen + len - 1) = ' ';
dst[len - 1] = ' ';
}
if (depth > NS_MAXDNSRCH || /* too many jumps? abort, it's a loop */
len > NS_MAXDNAME * NS_MAXDNSRCH) /* result too long? abort */
if (depth > NS_MAXDNSRCH /* too many jumps? abort, it's a loop */
|| len > NS_MAXDNAME * NS_MAXDNSRCH /* result too long? abort */
) {
return NULL;
}
}
if (!len) /* expanded string has 0 length? abort */
return NULL;
if (dst)
*(dst + plen + len - 1) = '\0';
if (!dst) { /* first pass? */
/* allocate dst buffer and copy pre */
unsigned plen = strlen(pre);
ret = dst = xmalloc(plen + len);
memcpy(dst, pre, plen);
dst += plen;
} else {
dst[len - 1] = '\0';
break;
}
}
return dst;
return ret;
}
/* Convert a domain name (src) from human-readable "foo.blah.com" format into

2
networking/udhcp/options.c
View File

@ -115,7 +115,7 @@ const uint8_t dhcp_option_lengths[] ALIGN1 = {
[OPTION_U16] = 2,
[OPTION_S16] = 2,
[OPTION_U32] = 4,
[OPTION_S32] = 4
[OPTION_S32] = 4,
};

8
networking/udhcp/options.h
View File

@ -19,11 +19,13 @@ enum {
OPTION_U16,
OPTION_S16,
OPTION_U32,
OPTION_S32
OPTION_S32,
};
#define OPTION_REQ 0x10 /* have the client request this option */
#define OPTION_LIST 0x20 /* There can be a list of 1 or more of these */
/* Client requests this option by default */
#define OPTION_REQ 0x10
/* There can be a list of 1 or more of these */
#define OPTION_LIST 0x20
/*****************************************************************/
/* Do not modify below here unless you know what you are doing!! */

33
networking/udhcp/script.c
View File

@ -14,7 +14,7 @@
/* get a rough idea of how long an option will be (rounding up...) */
static const uint8_t max_option_length[] = {
static const uint8_t len_of_option_as_string[] = {
[OPTION_IP] = sizeof("255.255.255.255 "),
[OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
[OPTION_STRING] = 1,
@ -30,17 +30,10 @@ static const uint8_t max_option_length[] = {
};
static inline int upper_length(int length, int opt_index)
{
return max_option_length[opt_index] *
(length / dhcp_option_lengths[opt_index]);
}
/* note: ip is a pointer to an IP in network order, possibly misaliged */
static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
{
return sprintf(dest, "%s%d.%d.%d.%d", pre, ip[0], ip[1], ip[2], ip[3]);
return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
}
@ -57,9 +50,10 @@ static int mton(uint32_t mask)
}
/* Allocate and fill with the text of option 'option'. */
static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
/* Create "opt_name=opt_value" string */
static char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
{
unsigned upper_length;
int len, type, optlen;
uint16_t val_u16;
int16_t val_s16;
@ -67,14 +61,16 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p,
int32_t val_s32;
char *dest, *ret;
len = option[OPT_LEN - 2];
/* option points to OPT_DATA, need to go back and get OPT_LEN */
len = option[OPT_LEN - OPT_DATA];
type = type_p->flags & TYPE_MASK;
optlen = dhcp_option_lengths[type];
upper_length = len_of_option_as_string[type] * (len / optlen);
dest = ret = xmalloc(upper_length(len, type) + strlen(opt_name) + 2);
dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
dest += sprintf(ret, "%s=", opt_name);
for (;;) {
while (len >= optlen) {
switch (type) {
case OPTION_IP_PAIR:
dest += sprint_nip(dest, "", option);
@ -114,15 +110,20 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p,
case OPTION_STR1035:
/* unpack option into dest; use ret for prefix (i.e., "optname=") */
dest = dname_dec(option, len, ret);
if (dest) {
free(ret);
return dest;
}
/* error. return "optname=" string */
return ret;
#endif
}
option += optlen;
len -= optlen;
if (len <= 0)
break;
dest += sprintf(dest, " ");
*dest++ = ' ';
*dest = '\0';
}
return ret;
}
@ -174,7 +175,7 @@ static char **fill_envp(struct dhcp_packet *packet)
temp = get_option(packet, dhcp_options[i].code);
if (!temp)
goto next;
*curr = alloc_fill_opts(temp, &dhcp_options[i], opt_name);
*curr = xmalloc_optname_optval(temp, &dhcp_options[i], opt_name);
putenv(*curr++);
/* Fill in a subnet bits option for things like /24 */