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nss: aiforaf: Decrease stack size by scoping off large buffers

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The 'buf', 'sa' and 'hints' stack allocated helper variables are never
used together. Decrease the stack memory usage by scoping them off into
do-while blocks.

In this instance we do not want to use dynamic allocation as this is the
NSS module.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Kristina Hanicova <khanicov@redhat.com>
This commit is contained in:
Peter Krempa 2022-09-20 13:16:58 +02:00
parent 575e7fe963
commit 9e5f2fe402
1 changed files with 51 additions and 36 deletions
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87
tools/nss/libvirt_nss.c
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@ -470,58 +470,73 @@ aiforaf(const char *name,
struct addrinfo **aip)
{
struct hostent resolved;
char buf[1024] = { 0 };
int err;
int herr;
struct addrinfo hints;
struct addrinfo *res0;
struct addrinfo *res;
char **addrList;
if (NSS_NAME(gethostbyname2)(name, af, &resolved,
buf, sizeof(buf),
&err, &herr) != NS_SUCCESS)
return;
/* Note: The do-while blocks in this function are used to scope off large
* stack allocated buffers, which are not needed at the same time */
do {
char buf[1024] = { 0 };
int herr;
if (NSS_NAME(gethostbyname2)(name, af, &resolved,
buf, sizeof(buf),
&err, &herr) != NS_SUCCESS)
return;
} while (false);
addrList = resolved.h_addr_list;
while (*addrList) {
union {
struct sockaddr sa;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
} sa = { 0 };
socklen_t salen;
void *address = *addrList;
char host[NI_MAXHOST];
struct addrinfo *res0;
struct addrinfo *res;
if (resolved.h_addrtype == AF_INET) {
sa.sin.sin_family = AF_INET;
memcpy(&sa.sin.sin_addr.s_addr,
address,
FAMILY_ADDRESS_SIZE(AF_INET));
salen = sizeof(sa.sin);
} else {
sa.sin6.sin6_family = AF_INET6;
memcpy(&sa.sin6.sin6_addr.s6_addr,
address,
FAMILY_ADDRESS_SIZE(AF_INET6));
salen = sizeof(sa.sin6);
}
do {
union {
struct sockaddr sa;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
} sa = { 0 };
socklen_t salen;
if ((err = getnameinfo(&sa.sa, salen,
host, sizeof(host),
NULL, 0,
NI_NUMERICHOST | NI_NUMERICSERV)) != 0) {
if (resolved.h_addrtype == AF_INET) {
sa.sin.sin_family = AF_INET;
memcpy(&sa.sin.sin_addr.s_addr,
address,
FAMILY_ADDRESS_SIZE(AF_INET));
salen = sizeof(sa.sin);
} else {
sa.sin6.sin6_family = AF_INET6;
memcpy(&sa.sin6.sin6_addr.s6_addr,
address,
FAMILY_ADDRESS_SIZE(AF_INET6));
salen = sizeof(sa.sin6);
}
err = getnameinfo(&sa.sa, salen,
host, sizeof(host),
NULL, 0,
NI_NUMERICHOST | NI_NUMERICSERV);
} while (false);
if (err != 0) {
ERROR("Cannot convert socket address to string: %s",
gai_strerror(err));
continue;
}
hints = *pai;
hints.ai_flags = AI_NUMERICHOST;
hints.ai_family = af;
do {
struct addrinfo hints;
if (getaddrinfo(host, NULL, &hints, &res0)) {
hints = *pai;
hints.ai_flags = AI_NUMERICHOST;
hints.ai_family = af;
err = getaddrinfo(host, NULL, &hints, &res0);
} while (false);
if (err != 0) {
addrList++;
continue;
}