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os: Fix a type error in the IPv6 XDMCP code 

Building with strict-aliasing rightly chirps here:

../os/xdmcp.c: In function ‘XdmcpRegisterConnection’:
../os/xdmcp.c:489:31: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
                     &((struct sockaddr_in6 *) &address)->sin6_addr.s6_addr[12];
                               ^~~~~~~~~~~~

We have "const char *address", so &address here is a char ** (i.e., it
points to the slot on the stack containing the pointer to the character
array passed in as an argument). Casting that to a struct sockaddr_in6 *
is wrong, because it means that area of the stack will be reinterpreted
as a struct sockaddr_in6.

Instead, cast address, not &address.

Signed-off-by: Adam Jackson <ajax@redhat.com>
This commit is contained in:
Adam Jackson 2017-12-13 14:53:56 -05:00
parent da4ffb2f6a
commit 652913cd94
1 changed files with 1 additions and 1 deletions
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2
os/xdmcp.c
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@ -486,7 +486,7 @@ XdmcpRegisterConnection(int type, const char *address, int addrlen)
IN6_IS_ADDR_V4MAPPED((const struct in6_addr *) address)) {
fromAddr = &((struct sockaddr_in *) &FromAddress)->sin_addr;
regAddr =
&((struct sockaddr_in6 *) &address)->sin6_addr.s6_addr[12];
&((struct sockaddr_in6 *) address)->sin6_addr.s6_addr[12];
regAddrlen = sizeof(struct in_addr);
}
}