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| author | Denis Vlasenko <vda.linux@googlemail.com> | 2009-04-12 19:03:01 +0000 |
|---|---|---|
| committer | Denis Vlasenko <vda.linux@googlemail.com> | 2009-04-12 19:03:01 +0000 |
| commit | ef1b439669f7f952633eea3879defb357224eb4c (patch) | |
| tree | b8170a8246d754661934927b82cb7090c4653e0c | |
| parent | e12c90217b8de612d2dfa429a71ad458b1754cf1 (diff) | |
| download | busybox-w32-ef1b439669f7f952633eea3879defb357224eb4c.tar.gz busybox-w32-ef1b439669f7f952633eea3879defb357224eb4c.tar.bz2 busybox-w32-ef1b439669f7f952633eea3879defb357224eb4c.zip | |
dnsd: stop using oversized buffer. trim comment.
| -rw-r--r-- | networking/dnsd.c | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/networking/dnsd.c b/networking/dnsd.c index 5dbaec1eb..56ede3fca 100644 --- a/networking/dnsd.c +++ b/networking/dnsd.c | |||
| @@ -24,15 +24,10 @@ | |||
| 24 | #define DEBUG 0 | 24 | #define DEBUG 0 |
| 25 | 25 | ||
| 26 | enum { | 26 | enum { |
| 27 | /* Can tweak this */ | 27 | /* can tweak this */ |
| 28 | DEFAULT_TTL = 120, | 28 | DEFAULT_TTL = 120, |
| 29 | 29 | ||
| 30 | /* Cannot get bigger packets than 512 per RFC1035. | 30 | /* cannot get bigger packets than 512 per RFC1035. */ |
| 31 | * In practice this can be set considerably smaller: | ||
| 32 | * Length of response packet is header (12B) + 2*type(4B) + 2*class(4B) + | ||
| 33 | * ttl(4B) + rlen(2B) + r (MAX_NAME_LEN = 21B) + | ||
| 34 | * 2*querystring (2 MAX_NAME_LEN = 42B), all together 90 Bytes | ||
| 35 | */ | ||
| 36 | MAX_PACK_LEN = 512, | 31 | MAX_PACK_LEN = 512, |
| 37 | IP_STRING_LEN = sizeof(".xxx.xxx.xxx.xxx"), | 32 | IP_STRING_LEN = sizeof(".xxx.xxx.xxx.xxx"), |
| 38 | MAX_NAME_LEN = IP_STRING_LEN - 1 + sizeof(".in-addr.arpa"), | 33 | MAX_NAME_LEN = IP_STRING_LEN - 1 + sizeof(".in-addr.arpa"), |
| @@ -225,9 +220,9 @@ OPCODE 0 standard query (QUERY) | |||
| 225 | 2 server status request (STATUS) | 220 | 2 server status request (STATUS) |
| 226 | AA Authoritative Answer - this bit is valid in responses. | 221 | AA Authoritative Answer - this bit is valid in responses. |
| 227 | Responding name server is an authority for the domain name | 222 | Responding name server is an authority for the domain name |
| 228 | in question section. Answer section may have multiple owner names | 223 | in question section. Answer section may have multiple owner names |
| 229 | because of aliases. The AA bit corresponds to the name which matches | 224 | because of aliases. The AA bit corresponds to the name which matches |
| 230 | the query name, or the first owner name in the answer section. | 225 | the query name, or the first owner name in the answer section. |
| 231 | TC TrunCation - this message was truncated. | 226 | TC TrunCation - this message was truncated. |
| 232 | RD Recursion Desired - this bit may be set in a query and | 227 | RD Recursion Desired - this bit may be set in a query and |
| 233 | is copied into the response. If RD is set, it directs | 228 | is copied into the response. If RD is set, it directs |
| @@ -240,10 +235,10 @@ RCODE Response code. | |||
| 240 | 0 No error condition | 235 | 0 No error condition |
| 241 | 1 Format error | 236 | 1 Format error |
| 242 | 2 Server failure - server was unable to process the query | 237 | 2 Server failure - server was unable to process the query |
| 243 | due to a problem with the name server. | 238 | due to a problem with the name server. |
| 244 | 3 Name Error - meaningful only for responses from | 239 | 3 Name Error - meaningful only for responses from |
| 245 | an authoritative name server. The referenced domain name | 240 | an authoritative name server. The referenced domain name |
| 246 | does not exist. | 241 | does not exist. |
| 247 | 4 Not Implemented. | 242 | 4 Not Implemented. |
| 248 | 5 Refused. | 243 | 5 Refused. |
| 249 | QDCOUNT number of entries in the question section. | 244 | QDCOUNT number of entries in the question section. |
| @@ -293,7 +288,7 @@ QTYPE a two octet type of the query. | |||
| 293 | 255 a request for all records | 288 | 255 a request for all records |
| 294 | QCLASS a two octet code that specifies the class of the query. | 289 | QCLASS a two octet code that specifies the class of the query. |
| 295 | 1 the Internet | 290 | 1 the Internet |
| 296 | (others are historic only) | 291 | (others are historic only) |
| 297 | 255 any class | 292 | 255 any class |
| 298 | 293 | ||
| 299 | 4.1.3. Resource record format | 294 | 4.1.3. Resource record format |
| @@ -464,9 +459,7 @@ int dnsd_main(int argc UNUSED_PARAM, char **argv) | |||
| 464 | unsigned lsa_size; | 459 | unsigned lsa_size; |
| 465 | int udps, opts; | 460 | int udps, opts; |
| 466 | uint16_t port = 53; | 461 | uint16_t port = 53; |
| 467 | /* Paranoid sizing: querystring x2 + ttl + outr_rlen + answstr */ | 462 | uint8_t buf[MAX_PACK_LEN + 1]; |
| 468 | /* I'd rather see process_packet() fixed instead... */ | ||
| 469 | uint8_t buf[MAX_PACK_LEN * 2 + 4 + 2 + (MAX_NAME_LEN+1)]; | ||
| 470 | 463 | ||
| 471 | opts = getopt32(argv, "vi:c:t:p:d", &listen_interface, &fileconf, &sttl, &sport); | 464 | opts = getopt32(argv, "vi:c:t:p:d", &listen_interface, &fileconf, &sttl, &sport); |
| 472 | //if (opts & 0x1) // -v | 465 | //if (opts & 0x1) // -v |
