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[PATCH] Fix incorrect getaddrinfo assertion trigger
- From: Allan McRae <allan at archlinux dot org>
- To: libc-alpha at sourceware dot org
- Cc: aurelien at aurel32 dot net
- Date: Fri, 30 Aug 2013 22:05:23 +1000
- Subject: [PATCH] Fix incorrect getaddrinfo assertion trigger
- Authentication-results: sourceware.org; auth=none
[BS #9954]
With the following /etc/hosts:
127.0.0.1 www.my-domain.es
127.0.1.1 www.my-domain.es
192.168.0.1 www.my-domain.es
Using getaddrinfo() on www.my-domain.es, trigger the following assertion:
../sysdeps/posix/getaddrinfo.c:1473: rfc3484_sort: Assertion
`src->results[i].native == -1 || src->results[i].native == a1_native' failed.
This is due to two different bugs:
- In rfc3484_sort() rule 7, src->results[i].native is assigned even if
src->results[i].index is -1, meaning that no interface is associated.
- In getaddrinfo() the source IP address used with the lo interface needs a
special case, as it can be any IP within 127.X.Y.Z.
---
This is a patch taken from bugzilla. I can not replicate it myself, even
with the attached testcase on bugzilla. However, I have users reporting this
issue that also can confirm this patch fixes the assertions for them. I
believe this patch is widely used by other distributions (at least Debian
and Fedora).
There is a negative comment by Ulrich here:
https://sourceware.org/bugzilla/show_bug.cgi?id=9954#c2
I think that comment is partially correct, in that it is hiding a bug from
a faulty DNS provider, in which case this patch is correct in that it
improves robustness. That is why this bug does not affect most people.
However, I am not fully confident about that assessment...
Can anyone replicate or confirm/correct my reasoning why most people can
not replicate?
20xx-xx-xx Aurelien Jarno <aurelien@aurel32.net>
[BS #9954]
* sysdeps/posix/getaddrinfo.c (rfc3484_sort): do not assign native
result if the result has no associated interface.
* sysdeps/posix/getaddrinfo.c (getaddrinfo): correctly detect
interface for all 127.X.Y.Z addresses.
sysdeps/posix/getaddrinfo.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c
index 52177e4..c0ded84 100644
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -1735,13 +1735,13 @@ rfc3484_sort (const void *p1, const void *p2, void *arg)
/* Fill in the results in all the records. */
for (int i = 0; i < src->nresults; ++i)
- if (src->results[i].index == a1_index)
+ if (a1_index != -1 && src->results[i].index == a1_index)
{
assert (src->results[i].native == -1
|| src->results[i].native == a1_native);
src->results[i].native = a1_native;
}
- else if (src->results[i].index == a2_index)
+ else if (a2_index != -1 && src->results[i].index == a2_index)
{
assert (src->results[i].native == -1
|| src->results[i].native == a2_native);
@@ -2601,7 +2601,14 @@ getaddrinfo (const char *name, const char *service,
tmp.addr[0] = 0;
tmp.addr[1] = 0;
tmp.addr[2] = htonl (0xffff);
- tmp.addr[3] = sinp->sin_addr.s_addr;
+ /* Special case for lo interface, the source address
+ being possibly different than the interface
+ address. */
+ if ((ntohl(sinp->sin_addr.s_addr) & 0xff000000)
+ == 0x7f000000)
+ tmp.addr[3] = htonl(0x7f000001);
+ else
+ tmp.addr[3] = sinp->sin_addr.s_addr;
}
else
{
--
1.8.4