mirror of
https://github.com/crosstool-ng/crosstool-ng.git
synced 2024-12-19 04:47:52 +00:00
Add patch for glibc 2.22 for CVE-2015-7547.
This resolves a vulnerability related to getaddrinfo().
This commit is contained in:
Reser, Ben
parent
d7339f50a2
commit
9c7a41ea64
551
patches/glibc/2.22/120-cve-2105-7547-getaddrinfo-stack.patch
Normal file
551
patches/glibc/2.22/120-cve-2105-7547-getaddrinfo-stack.patch
Normal file
@ -0,0 +1,551 @@
|
||||
diff -ruN glibc-2.22.orig/resolv/nss_dns/dns-host.c glibc-2.22/resolv/nss_dns/dns-host.c
|
||||
--- glibc-2.22.orig/resolv/nss_dns/dns-host.c 2015-08-04 23:42:21.000000000 -0700
|
||||
+++ glibc-2.22/resolv/nss_dns/dns-host.c 2016-02-16 13:38:38.000000000 -0800
|
||||
@@ -1031,7 +1031,10 @@
|
||||
int h_namelen = 0;
|
||||
|
||||
if (ancount == 0)
|
||||
- return NSS_STATUS_NOTFOUND;
|
||||
+ {
|
||||
+ *h_errnop = HOST_NOT_FOUND;
|
||||
+ return NSS_STATUS_NOTFOUND;
|
||||
+ }
|
||||
|
||||
while (ancount-- > 0 && cp < end_of_message && had_error == 0)
|
||||
{
|
||||
@@ -1208,7 +1211,14 @@
|
||||
/* Special case here: if the resolver sent a result but it only
|
||||
contains a CNAME while we are looking for a T_A or T_AAAA record,
|
||||
we fail with NOTFOUND instead of TRYAGAIN. */
|
||||
- return canon == NULL ? NSS_STATUS_TRYAGAIN : NSS_STATUS_NOTFOUND;
|
||||
+ if (canon != NULL)
|
||||
+ {
|
||||
+ *h_errnop = HOST_NOT_FOUND;
|
||||
+ return NSS_STATUS_NOTFOUND;
|
||||
+ }
|
||||
+
|
||||
+ *h_errnop = NETDB_INTERNAL;
|
||||
+ return NSS_STATUS_TRYAGAIN;
|
||||
}
|
||||
|
||||
|
||||
@@ -1222,11 +1232,101 @@
|
||||
|
||||
enum nss_status status = NSS_STATUS_NOTFOUND;
|
||||
|
||||
+ /* Combining the NSS status of two distinct queries requires some
|
||||
+ compromise and attention to symmetry (A or AAAA queries can be
|
||||
+ returned in any order). What follows is a breakdown of how this
|
||||
+ code is expected to work and why. We discuss only SUCCESS,
|
||||
+ TRYAGAIN, NOTFOUND and UNAVAIL, since they are the only returns
|
||||
+ that apply (though RETURN and MERGE exist). We make a distinction
|
||||
+ between TRYAGAIN (recoverable) and TRYAGAIN' (not-recoverable).
|
||||
+ A recoverable TRYAGAIN is almost always due to buffer size issues
|
||||
+ and returns ERANGE in errno and the caller is expected to retry
|
||||
+ with a larger buffer.
|
||||
+
|
||||
+ Lastly, you may be tempted to make significant changes to the
|
||||
+ conditions in this code to bring about symmetry between responses.
|
||||
+ Please don't change anything without due consideration for
|
||||
+ expected application behaviour. Some of the synthesized responses
|
||||
+ aren't very well thought out and sometimes appear to imply that
|
||||
+ IPv4 responses are always answer 1, and IPv6 responses are always
|
||||
+ answer 2, but that's not true (see the implemetnation of send_dg
|
||||
+ and send_vc to see response can arrive in any order, particlarly
|
||||
+ for UDP). However, we expect it holds roughly enough of the time
|
||||
+ that this code works, but certainly needs to be fixed to make this
|
||||
+ a more robust implementation.
|
||||
+
|
||||
+ ----------------------------------------------
|
||||
+ | Answer 1 Status / | Synthesized | Reason |
|
||||
+ | Answer 2 Status | Status | |
|
||||
+ |--------------------------------------------|
|
||||
+ | SUCCESS/SUCCESS | SUCCESS | [1] |
|
||||
+ | SUCCESS/TRYAGAIN | TRYAGAIN | [5] |
|
||||
+ | SUCCESS/TRYAGAIN' | SUCCESS | [1] |
|
||||
+ | SUCCESS/NOTFOUND | SUCCESS | [1] |
|
||||
+ | SUCCESS/UNAVAIL | SUCCESS | [1] |
|
||||
+ | TRYAGAIN/SUCCESS | TRYAGAIN | [2] |
|
||||
+ | TRYAGAIN/TRYAGAIN | TRYAGAIN | [2] |
|
||||
+ | TRYAGAIN/TRYAGAIN' | TRYAGAIN | [2] |
|
||||
+ | TRYAGAIN/NOTFOUND | TRYAGAIN | [2] |
|
||||
+ | TRYAGAIN/UNAVAIL | TRYAGAIN | [2] |
|
||||
+ | TRYAGAIN'/SUCCESS | SUCCESS | [3] |
|
||||
+ | TRYAGAIN'/TRYAGAIN | TRYAGAIN | [3] |
|
||||
+ | TRYAGAIN'/TRYAGAIN' | TRYAGAIN' | [3] |
|
||||
+ | TRYAGAIN'/NOTFOUND | TRYAGAIN' | [3] |
|
||||
+ | TRYAGAIN'/UNAVAIL | UNAVAIL | [3] |
|
||||
+ | NOTFOUND/SUCCESS | SUCCESS | [3] |
|
||||
+ | NOTFOUND/TRYAGAIN | TRYAGAIN | [3] |
|
||||
+ | NOTFOUND/TRYAGAIN' | TRYAGAIN' | [3] |
|
||||
+ | NOTFOUND/NOTFOUND | NOTFOUND | [3] |
|
||||
+ | NOTFOUND/UNAVAIL | UNAVAIL | [3] |
|
||||
+ | UNAVAIL/SUCCESS | UNAVAIL | [4] |
|
||||
+ | UNAVAIL/TRYAGAIN | UNAVAIL | [4] |
|
||||
+ | UNAVAIL/TRYAGAIN' | UNAVAIL | [4] |
|
||||
+ | UNAVAIL/NOTFOUND | UNAVAIL | [4] |
|
||||
+ | UNAVAIL/UNAVAIL | UNAVAIL | [4] |
|
||||
+ ----------------------------------------------
|
||||
+
|
||||
+ [1] If the first response is a success we return success.
|
||||
+ This ignores the state of the second answer and in fact
|
||||
+ incorrectly sets errno and h_errno to that of the second
|
||||
+ answer. However because the response is a success we ignore
|
||||
+ *errnop and *h_errnop (though that means you touched errno on
|
||||
+ success). We are being conservative here and returning the
|
||||
+ likely IPv4 response in the first answer as a success.
|
||||
+
|
||||
+ [2] If the first response is a recoverable TRYAGAIN we return
|
||||
+ that instead of looking at the second response. The
|
||||
+ expectation here is that we have failed to get an IPv4 response
|
||||
+ and should retry both queries.
|
||||
+
|
||||
+ [3] If the first response was not a SUCCESS and the second
|
||||
+ response is not NOTFOUND (had a SUCCESS, need to TRYAGAIN,
|
||||
+ or failed entirely e.g. TRYAGAIN' and UNAVAIL) then use the
|
||||
+ result from the second response, otherwise the first responses
|
||||
+ status is used. Again we have some odd side-effects when the
|
||||
+ second response is NOTFOUND because we overwrite *errnop and
|
||||
+ *h_errnop that means that a first answer of NOTFOUND might see
|
||||
+ its *errnop and *h_errnop values altered. Whether it matters
|
||||
+ in practice that a first response NOTFOUND has the wrong
|
||||
+ *errnop and *h_errnop is undecided.
|
||||
+
|
||||
+ [4] If the first response is UNAVAIL we return that instead of
|
||||
+ looking at the second response. The expectation here is that
|
||||
+ it will have failed similarly e.g. configuration failure.
|
||||
+
|
||||
+ [5] Testing this code is complicated by the fact that truncated
|
||||
+ second response buffers might be returned as SUCCESS if the
|
||||
+ first answer is a SUCCESS. To fix this we add symmetry to
|
||||
+ TRYAGAIN with the second response. If the second response
|
||||
+ is a recoverable error we now return TRYAGIN even if the first
|
||||
+ response was SUCCESS. */
|
||||
+
|
||||
if (anslen1 > 0)
|
||||
status = gaih_getanswer_slice(answer1, anslen1, qname,
|
||||
&pat, &buffer, &buflen,
|
||||
errnop, h_errnop, ttlp,
|
||||
&first);
|
||||
+
|
||||
if ((status == NSS_STATUS_SUCCESS || status == NSS_STATUS_NOTFOUND
|
||||
|| (status == NSS_STATUS_TRYAGAIN
|
||||
/* We want to look at the second answer in case of an
|
||||
@@ -1242,8 +1342,15 @@
|
||||
&pat, &buffer, &buflen,
|
||||
errnop, h_errnop, ttlp,
|
||||
&first);
|
||||
+ /* Use the second response status in some cases. */
|
||||
if (status != NSS_STATUS_SUCCESS && status2 != NSS_STATUS_NOTFOUND)
|
||||
status = status2;
|
||||
+ /* Do not return a truncated second response (unless it was
|
||||
+ unavoidable e.g. unrecoverable TRYAGAIN). */
|
||||
+ if (status == NSS_STATUS_SUCCESS
|
||||
+ && (status2 == NSS_STATUS_TRYAGAIN
|
||||
+ && *errnop == ERANGE && *h_errnop != NO_RECOVERY))
|
||||
+ status = NSS_STATUS_TRYAGAIN;
|
||||
}
|
||||
|
||||
return status;
|
||||
diff -ruN glibc-2.22.orig/resolv/res_query.c glibc-2.22/resolv/res_query.c
|
||||
--- glibc-2.22.orig/resolv/res_query.c 2015-08-04 23:42:21.000000000 -0700
|
||||
+++ glibc-2.22/resolv/res_query.c 2016-02-16 13:38:38.000000000 -0800
|
||||
@@ -396,6 +396,7 @@
|
||||
{
|
||||
free (*answerp2);
|
||||
*answerp2 = NULL;
|
||||
+ *nanswerp2 = 0;
|
||||
*answerp2_malloced = 0;
|
||||
}
|
||||
}
|
||||
@@ -447,6 +448,7 @@
|
||||
{
|
||||
free (*answerp2);
|
||||
*answerp2 = NULL;
|
||||
+ *nanswerp2 = 0;
|
||||
*answerp2_malloced = 0;
|
||||
}
|
||||
|
||||
@@ -521,6 +523,7 @@
|
||||
{
|
||||
free (*answerp2);
|
||||
*answerp2 = NULL;
|
||||
+ *nanswerp2 = 0;
|
||||
*answerp2_malloced = 0;
|
||||
}
|
||||
if (saved_herrno != -1)
|
||||
diff -ruN glibc-2.22.orig/resolv/res_send.c glibc-2.22/resolv/res_send.c
|
||||
--- glibc-2.22.orig/resolv/res_send.c 2015-08-04 23:42:21.000000000 -0700
|
||||
+++ glibc-2.22/resolv/res_send.c 2016-02-16 13:43:59.000000000 -0800
|
||||
@@ -1,3 +1,20 @@
|
||||
+/* Copyright (C) 2016 Free Software Foundation, Inc.
|
||||
+ This file is part of the GNU C Library.
|
||||
+
|
||||
+ The GNU C Library is free software; you can redistribute it and/or
|
||||
+ modify it under the terms of the GNU Lesser General Public
|
||||
+ License as published by the Free Software Foundation; either
|
||||
+ version 2.1 of the License, or (at your option) any later version.
|
||||
+
|
||||
+ The GNU C Library is distributed in the hope that it will be useful,
|
||||
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
+ Lesser General Public License for more details.
|
||||
+
|
||||
+ You should have received a copy of the GNU Lesser General Public
|
||||
+ License along with the GNU C Library; if not, see
|
||||
+ <http://www.gnu.org/licenses/>. */
|
||||
+
|
||||
/*
|
||||
* Copyright (c) 1985, 1989, 1993
|
||||
* The Regents of the University of California. All rights reserved.
|
||||
@@ -363,6 +380,8 @@
|
||||
#ifdef USE_HOOKS
|
||||
if (__glibc_unlikely (statp->qhook || statp->rhook)) {
|
||||
if (anssiz < MAXPACKET && ansp) {
|
||||
+ /* Always allocate MAXPACKET, callers expect
|
||||
+ this specific size. */
|
||||
u_char *buf = malloc (MAXPACKET);
|
||||
if (buf == NULL)
|
||||
return (-1);
|
||||
@@ -638,6 +657,77 @@
|
||||
return (struct sockaddr *) (void *) &statp->nsaddr_list[n];
|
||||
}
|
||||
|
||||
+/* The send_vc function is responsible for sending a DNS query over TCP
|
||||
+ to the nameserver numbered NS from the res_state STATP i.e.
|
||||
+ EXT(statp).nssocks[ns]. The function supports sending both IPv4 and
|
||||
+ IPv6 queries at the same serially on the same socket.
|
||||
+
|
||||
+ Please note that for TCP there is no way to disable sending both
|
||||
+ queries, unlike UDP, which honours RES_SNGLKUP and RES_SNGLKUPREOP
|
||||
+ and sends the queries serially and waits for the result after each
|
||||
+ sent query. This implemetnation should be corrected to honour these
|
||||
+ options.
|
||||
+
|
||||
+ Please also note that for TCP we send both queries over the same
|
||||
+ socket one after another. This technically violates best practice
|
||||
+ since the server is allowed to read the first query, respond, and
|
||||
+ then close the socket (to service another client). If the server
|
||||
+ does this, then the remaining second query in the socket data buffer
|
||||
+ will cause the server to send the client an RST which will arrive
|
||||
+ asynchronously and the client's OS will likely tear down the socket
|
||||
+ receive buffer resulting in a potentially short read and lost
|
||||
+ response data. This will force the client to retry the query again,
|
||||
+ and this process may repeat until all servers and connection resets
|
||||
+ are exhausted and then the query will fail. It's not known if this
|
||||
+ happens with any frequency in real DNS server implementations. This
|
||||
+ implementation should be corrected to use two sockets by default for
|
||||
+ parallel queries.
|
||||
+
|
||||
+ The query stored in BUF of BUFLEN length is sent first followed by
|
||||
+ the query stored in BUF2 of BUFLEN2 length. Queries are sent
|
||||
+ serially on the same socket.
|
||||
+
|
||||
+ Answers to the query are stored firstly in *ANSP up to a max of
|
||||
+ *ANSSIZP bytes. If more than *ANSSIZP bytes are needed and ANSCP
|
||||
+ is non-NULL (to indicate that modifying the answer buffer is allowed)
|
||||
+ then malloc is used to allocate a new response buffer and ANSCP and
|
||||
+ ANSP will both point to the new buffer. If more than *ANSSIZP bytes
|
||||
+ are needed but ANSCP is NULL, then as much of the response as
|
||||
+ possible is read into the buffer, but the results will be truncated.
|
||||
+ When truncation happens because of a small answer buffer the DNS
|
||||
+ packets header feild TC will bet set to 1, indicating a truncated
|
||||
+ message and the rest of the socket data will be read and discarded.
|
||||
+
|
||||
+ Answers to the query are stored secondly in *ANSP2 up to a max of
|
||||
+ *ANSSIZP2 bytes, with the actual response length stored in
|
||||
+ *RESPLEN2. If more than *ANSSIZP bytes are needed and ANSP2
|
||||
+ is non-NULL (required for a second query) then malloc is used to
|
||||
+ allocate a new response buffer, *ANSSIZP2 is set to the new buffer
|
||||
+ size and *ANSP2_MALLOCED is set to 1.
|
||||
+
|
||||
+ The ANSP2_MALLOCED argument will eventually be removed as the
|
||||
+ change in buffer pointer can be used to detect the buffer has
|
||||
+ changed and that the caller should use free on the new buffer.
|
||||
+
|
||||
+ Note that the answers may arrive in any order from the server and
|
||||
+ therefore the first and second answer buffers may not correspond to
|
||||
+ the first and second queries.
|
||||
+
|
||||
+ It is not supported to call this function with a non-NULL ANSP2
|
||||
+ but a NULL ANSCP. Put another way, you can call send_vc with a
|
||||
+ single unmodifiable buffer or two modifiable buffers, but no other
|
||||
+ combination is supported.
|
||||
+
|
||||
+ It is the caller's responsibility to free the malloc allocated
|
||||
+ buffers by detecting that the pointers have changed from their
|
||||
+ original values i.e. *ANSCP or *ANSP2 has changed.
|
||||
+
|
||||
+ If errors are encountered then *TERRNO is set to an appropriate
|
||||
+ errno value and a zero result is returned for a recoverable error,
|
||||
+ and a less-than zero result is returned for a non-recoverable error.
|
||||
+
|
||||
+ If no errors are encountered then *TERRNO is left unmodified and
|
||||
+ a the length of the first response in bytes is returned. */
|
||||
static int
|
||||
send_vc(res_state statp,
|
||||
const u_char *buf, int buflen, const u_char *buf2, int buflen2,
|
||||
@@ -647,11 +737,7 @@
|
||||
{
|
||||
const HEADER *hp = (HEADER *) buf;
|
||||
const HEADER *hp2 = (HEADER *) buf2;
|
||||
- u_char *ans = *ansp;
|
||||
- int orig_anssizp = *anssizp;
|
||||
- // XXX REMOVE
|
||||
- // int anssiz = *anssizp;
|
||||
- HEADER *anhp = (HEADER *) ans;
|
||||
+ HEADER *anhp = (HEADER *) *ansp;
|
||||
struct sockaddr *nsap = get_nsaddr (statp, ns);
|
||||
int truncating, connreset, n;
|
||||
/* On some architectures compiler might emit a warning indicating
|
||||
@@ -743,6 +829,8 @@
|
||||
* Receive length & response
|
||||
*/
|
||||
int recvresp1 = 0;
|
||||
+ /* Skip the second response if there is no second query.
|
||||
+ To do that we mark the second response as received. */
|
||||
int recvresp2 = buf2 == NULL;
|
||||
uint16_t rlen16;
|
||||
read_len:
|
||||
@@ -779,40 +867,14 @@
|
||||
u_char **thisansp;
|
||||
int *thisresplenp;
|
||||
if ((recvresp1 | recvresp2) == 0 || buf2 == NULL) {
|
||||
+ /* We have not received any responses
|
||||
+ yet or we only have one response to
|
||||
+ receive. */
|
||||
thisanssizp = anssizp;
|
||||
thisansp = anscp ?: ansp;
|
||||
assert (anscp != NULL || ansp2 == NULL);
|
||||
thisresplenp = &resplen;
|
||||
} else {
|
||||
- if (*anssizp != MAXPACKET) {
|
||||
- /* No buffer allocated for the first
|
||||
- reply. We can try to use the rest
|
||||
- of the user-provided buffer. */
|
||||
-#if __GNUC_PREREQ (4, 7)
|
||||
- DIAG_PUSH_NEEDS_COMMENT;
|
||||
- DIAG_IGNORE_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
|
||||
-#endif
|
||||
-#if _STRING_ARCH_unaligned
|
||||
- *anssizp2 = orig_anssizp - resplen;
|
||||
- *ansp2 = *ansp + resplen;
|
||||
-#else
|
||||
- int aligned_resplen
|
||||
- = ((resplen + __alignof__ (HEADER) - 1)
|
||||
- & ~(__alignof__ (HEADER) - 1));
|
||||
- *anssizp2 = orig_anssizp - aligned_resplen;
|
||||
- *ansp2 = *ansp + aligned_resplen;
|
||||
-#endif
|
||||
-#if __GNUC_PREREQ (4, 7)
|
||||
- DIAG_POP_NEEDS_COMMENT;
|
||||
-#endif
|
||||
- } else {
|
||||
- /* The first reply did not fit into the
|
||||
- user-provided buffer. Maybe the second
|
||||
- answer will. */
|
||||
- *anssizp2 = orig_anssizp;
|
||||
- *ansp2 = *ansp;
|
||||
- }
|
||||
-
|
||||
thisanssizp = anssizp2;
|
||||
thisansp = ansp2;
|
||||
thisresplenp = resplen2;
|
||||
@@ -820,10 +882,14 @@
|
||||
anhp = (HEADER *) *thisansp;
|
||||
|
||||
*thisresplenp = rlen;
|
||||
- if (rlen > *thisanssizp) {
|
||||
- /* Yes, we test ANSCP here. If we have two buffers
|
||||
- both will be allocatable. */
|
||||
- if (__glibc_likely (anscp != NULL)) {
|
||||
+ /* Is the answer buffer too small? */
|
||||
+ if (*thisanssizp < rlen) {
|
||||
+ /* If the current buffer is not the the static
|
||||
+ user-supplied buffer then we can reallocate
|
||||
+ it. */
|
||||
+ if (thisansp != NULL && thisansp != ansp) {
|
||||
+ /* Always allocate MAXPACKET, callers expect
|
||||
+ this specific size. */
|
||||
u_char *newp = malloc (MAXPACKET);
|
||||
if (newp == NULL) {
|
||||
*terrno = ENOMEM;
|
||||
@@ -835,6 +901,9 @@
|
||||
if (thisansp == ansp2)
|
||||
*ansp2_malloced = 1;
|
||||
anhp = (HEADER *) newp;
|
||||
+ /* A uint16_t can't be larger than MAXPACKET
|
||||
+ thus it's safe to allocate MAXPACKET but
|
||||
+ read RLEN bytes instead. */
|
||||
len = rlen;
|
||||
} else {
|
||||
Dprint(statp->options & RES_DEBUG,
|
||||
@@ -997,6 +1066,66 @@
|
||||
return 1;
|
||||
}
|
||||
|
||||
+/* The send_dg function is responsible for sending a DNS query over UDP
|
||||
+ to the nameserver numbered NS from the res_state STATP i.e.
|
||||
+ EXT(statp).nssocks[ns]. The function supports IPv4 and IPv6 queries
|
||||
+ along with the ability to send the query in parallel for both stacks
|
||||
+ (default) or serially (RES_SINGLKUP). It also supports serial lookup
|
||||
+ with a close and reopen of the socket used to talk to the server
|
||||
+ (RES_SNGLKUPREOP) to work around broken name servers.
|
||||
+
|
||||
+ The query stored in BUF of BUFLEN length is sent first followed by
|
||||
+ the query stored in BUF2 of BUFLEN2 length. Queries are sent
|
||||
+ in parallel (default) or serially (RES_SINGLKUP or RES_SNGLKUPREOP).
|
||||
+
|
||||
+ Answers to the query are stored firstly in *ANSP up to a max of
|
||||
+ *ANSSIZP bytes. If more than *ANSSIZP bytes are needed and ANSCP
|
||||
+ is non-NULL (to indicate that modifying the answer buffer is allowed)
|
||||
+ then malloc is used to allocate a new response buffer and ANSCP and
|
||||
+ ANSP will both point to the new buffer. If more than *ANSSIZP bytes
|
||||
+ are needed but ANSCP is NULL, then as much of the response as
|
||||
+ possible is read into the buffer, but the results will be truncated.
|
||||
+ When truncation happens because of a small answer buffer the DNS
|
||||
+ packets header feild TC will bet set to 1, indicating a truncated
|
||||
+ message, while the rest of the UDP packet is discarded.
|
||||
+
|
||||
+ Answers to the query are stored secondly in *ANSP2 up to a max of
|
||||
+ *ANSSIZP2 bytes, with the actual response length stored in
|
||||
+ *RESPLEN2. If more than *ANSSIZP bytes are needed and ANSP2
|
||||
+ is non-NULL (required for a second query) then malloc is used to
|
||||
+ allocate a new response buffer, *ANSSIZP2 is set to the new buffer
|
||||
+ size and *ANSP2_MALLOCED is set to 1.
|
||||
+
|
||||
+ The ANSP2_MALLOCED argument will eventually be removed as the
|
||||
+ change in buffer pointer can be used to detect the buffer has
|
||||
+ changed and that the caller should use free on the new buffer.
|
||||
+
|
||||
+ Note that the answers may arrive in any order from the server and
|
||||
+ therefore the first and second answer buffers may not correspond to
|
||||
+ the first and second queries.
|
||||
+
|
||||
+ It is not supported to call this function with a non-NULL ANSP2
|
||||
+ but a NULL ANSCP. Put another way, you can call send_vc with a
|
||||
+ single unmodifiable buffer or two modifiable buffers, but no other
|
||||
+ combination is supported.
|
||||
+
|
||||
+ It is the caller's responsibility to free the malloc allocated
|
||||
+ buffers by detecting that the pointers have changed from their
|
||||
+ original values i.e. *ANSCP or *ANSP2 has changed.
|
||||
+
|
||||
+ If an answer is truncated because of UDP datagram DNS limits then
|
||||
+ *V_CIRCUIT is set to 1 and the return value non-zero to indicate to
|
||||
+ the caller to retry with TCP. The value *GOTSOMEWHERE is set to 1
|
||||
+ if any progress was made reading a response from the nameserver and
|
||||
+ is used by the caller to distinguish between ECONNREFUSED and
|
||||
+ ETIMEDOUT (the latter if *GOTSOMEWHERE is 1).
|
||||
+
|
||||
+ If errors are encountered then *TERRNO is set to an appropriate
|
||||
+ errno value and a zero result is returned for a recoverable error,
|
||||
+ and a less-than zero result is returned for a non-recoverable error.
|
||||
+
|
||||
+ If no errors are encountered then *TERRNO is left unmodified and
|
||||
+ a the length of the first response in bytes is returned. */
|
||||
static int
|
||||
send_dg(res_state statp,
|
||||
const u_char *buf, int buflen, const u_char *buf2, int buflen2,
|
||||
@@ -1006,8 +1135,6 @@
|
||||
{
|
||||
const HEADER *hp = (HEADER *) buf;
|
||||
const HEADER *hp2 = (HEADER *) buf2;
|
||||
- u_char *ans = *ansp;
|
||||
- int orig_anssizp = *anssizp;
|
||||
struct timespec now, timeout, finish;
|
||||
struct pollfd pfd[1];
|
||||
int ptimeout;
|
||||
@@ -1040,6 +1167,8 @@
|
||||
int need_recompute = 0;
|
||||
int nwritten = 0;
|
||||
int recvresp1 = 0;
|
||||
+ /* Skip the second response if there is no second query.
|
||||
+ To do that we mark the second response as received. */
|
||||
int recvresp2 = buf2 == NULL;
|
||||
pfd[0].fd = EXT(statp).nssocks[ns];
|
||||
pfd[0].events = POLLOUT;
|
||||
@@ -1203,55 +1332,56 @@
|
||||
int *thisresplenp;
|
||||
|
||||
if ((recvresp1 | recvresp2) == 0 || buf2 == NULL) {
|
||||
+ /* We have not received any responses
|
||||
+ yet or we only have one response to
|
||||
+ receive. */
|
||||
thisanssizp = anssizp;
|
||||
thisansp = anscp ?: ansp;
|
||||
assert (anscp != NULL || ansp2 == NULL);
|
||||
thisresplenp = &resplen;
|
||||
} else {
|
||||
- if (*anssizp != MAXPACKET) {
|
||||
- /* No buffer allocated for the first
|
||||
- reply. We can try to use the rest
|
||||
- of the user-provided buffer. */
|
||||
-#if _STRING_ARCH_unaligned
|
||||
- *anssizp2 = orig_anssizp - resplen;
|
||||
- *ansp2 = *ansp + resplen;
|
||||
-#else
|
||||
- int aligned_resplen
|
||||
- = ((resplen + __alignof__ (HEADER) - 1)
|
||||
- & ~(__alignof__ (HEADER) - 1));
|
||||
- *anssizp2 = orig_anssizp - aligned_resplen;
|
||||
- *ansp2 = *ansp + aligned_resplen;
|
||||
-#endif
|
||||
- } else {
|
||||
- /* The first reply did not fit into the
|
||||
- user-provided buffer. Maybe the second
|
||||
- answer will. */
|
||||
- *anssizp2 = orig_anssizp;
|
||||
- *ansp2 = *ansp;
|
||||
- }
|
||||
-
|
||||
thisanssizp = anssizp2;
|
||||
thisansp = ansp2;
|
||||
thisresplenp = resplen2;
|
||||
}
|
||||
|
||||
if (*thisanssizp < MAXPACKET
|
||||
- /* Yes, we test ANSCP here. If we have two buffers
|
||||
- both will be allocatable. */
|
||||
- && anscp
|
||||
+ /* If the current buffer is not the the static
|
||||
+ user-supplied buffer then we can reallocate
|
||||
+ it. */
|
||||
+ && (thisansp != NULL && thisansp != ansp)
|
||||
#ifdef FIONREAD
|
||||
+ /* Is the size too small? */
|
||||
&& (ioctl (pfd[0].fd, FIONREAD, thisresplenp) < 0
|
||||
|| *thisanssizp < *thisresplenp)
|
||||
#endif
|
||||
) {
|
||||
+ /* Always allocate MAXPACKET, callers expect
|
||||
+ this specific size. */
|
||||
u_char *newp = malloc (MAXPACKET);
|
||||
if (newp != NULL) {
|
||||
- *anssizp = MAXPACKET;
|
||||
- *thisansp = ans = newp;
|
||||
+ *thisanssizp = MAXPACKET;
|
||||
+ *thisansp = newp;
|
||||
if (thisansp == ansp2)
|
||||
*ansp2_malloced = 1;
|
||||
}
|
||||
}
|
||||
+ /* We could end up with truncation if anscp was NULL
|
||||
+ (not allowed to change caller's buffer) and the
|
||||
+ response buffer size is too small. This isn't a
|
||||
+ reliable way to detect truncation because the ioctl
|
||||
+ may be an inaccurate report of the UDP message size.
|
||||
+ Therefore we use this only to issue debug output.
|
||||
+ To do truncation accurately with UDP we need
|
||||
+ MSG_TRUNC which is only available on Linux. We
|
||||
+ can abstract out the Linux-specific feature in the
|
||||
+ future to detect truncation. */
|
||||
+ if (__glibc_unlikely (*thisanssizp < *thisresplenp)) {
|
||||
+ Dprint(statp->options & RES_DEBUG,
|
||||
+ (stdout, ";; response may be truncated (UDP)\n")
|
||||
+ );
|
||||
+ }
|
||||
+
|
||||
HEADER *anhp = (HEADER *) *thisansp;
|
||||
socklen_t fromlen = sizeof(struct sockaddr_in6);
|
||||
assert (sizeof(from) <= fromlen);
|
||||
Loading…
Reference in New Issue
Block a user