diff options
| -rw-r--r-- | dhcp-common.c | 65 | ||||
| -rw-r--r-- | dhcp-common.h | 1 |
2 files changed, 31 insertions, 35 deletions
diff --git a/dhcp-common.c b/dhcp-common.c index a3764f1..588684e 100644 --- a/dhcp-common.c +++ b/dhcp-common.c @@ -522,51 +522,43 @@ print_string(char *dst, size_t len, int type, const uint8_t *data, size_t dl) return (ssize_t)bytes; } -#define ADDRSZ 4 #define ADDR6SZ 16 static size_t dhcp_optlen(const struct dhcp_opt *opt, size_t dl) { size_t sz; - if (dl == 0) + if (opt->type & ADDRIPV6) + sz = ADDR6SZ; + else if (opt->type & (UINT32 | ADDRIPV4)) + sz = sizeof(uint32_t); + else if (opt->type & UINT16) + sz = sizeof(uint16_t); + else if (opt->type & (UINT8 | BITFLAG)) + sz = sizeof(uint8_t); + else if (opt->type & FLAG) return 0; - - if (opt->type == 0 || - opt->type & (STRING | BINHEX | RFC3442 | RFC5969)) - { + else { + /* All other types are variable length */ if (opt->len) { - if ((size_t)opt->len > dl) - return 0; - return (size_t)opt->len; + if ((size_t)opt->len > dl) { + errno = ENODATA; + return -1; + } + return (ssize_t)opt->len; } - return dl; - } - - if ((opt->type & (ADDRIPV4 | ARRAY)) == (ADDRIPV4 | ARRAY)) { - if (dl < ADDRSZ) - return 0; - return dl - (dl % ADDRSZ); + return (ssize_t)dl; } - - if ((opt->type & (ADDRIPV6 | ARRAY)) == (ADDRIPV6 | ARRAY)) { - if (dl < ADDR6SZ) - return 0; - return dl - (dl % ADDR6SZ); + if (dl < sz) { + errno = ENODATA; + return -1; } - if (opt->type & (UINT32 | ADDRIPV4)) - sz = sizeof(uint32_t); - else if (opt->type & UINT16) - sz = sizeof(uint16_t); - else if (opt->type & UINT8) - sz = sizeof(uint8_t); - else if (opt->type & ADDRIPV6) - sz = ADDR6SZ; - else - /* If we don't know the size, assume it's valid */ - return dl; - return (dl < sz ? 0 : sz); + /* Trim any extra data. + * Maybe we need a settng to reject DHCP options with extra data? */ + if (opt->type & ARRAY) + return (ssize_t)(dl - (dl % sz)); + return (ssize_t)sz; } #ifdef INET6 @@ -766,8 +758,11 @@ dhcp_envoption1(struct dhcpcd_ctx *ctx, char **env, const char *prefix, size_t e; char *v, *val; - if (opt->len && opt->len < ol) - ol = opt->len; + /* Ensure a valid length */ + ol = (size_t)dhcp_optlen(opt, ol); + if ((ssize_t)ol == -1) + return 0; + len = print_option(NULL, 0, opt->type, od, ol, ifname); if (len < 0) return 0; diff --git a/dhcp-common.h b/dhcp-common.h index a3d62fc..a87d32a 100644 --- a/dhcp-common.h +++ b/dhcp-common.h @@ -66,6 +66,7 @@ #define RAW (1 << 23) #define ESCSTRING (1 << 24) #define ESCFILE (1 << 25) +#define BITFLAG (1 << 26) struct dhcp_opt { uint32_t option; /* Also used for IANA Enterpise Number */ |