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>
---
tools/nss/libvirt_nss.c | 97 +++++++++++++++++++++++------------------
1 file changed, 54 insertions(+), 43 deletions(-)
diff --git a/tools/nss/libvirt_nss.c b/tools/nss/libvirt_nss.c
index 37720bf4ae..dff3c034bf 100644
--- a/tools/nss/libvirt_nss.c
+++ b/tools/nss/libvirt_nss.c
@@ -470,61 +470,72 @@ 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;
+
+ do {
+ union {
+ struct sockaddr sa;
+ struct sockaddr_in sin;
+ struct sockaddr_in6 sin6;
+ } sa = { 0 };
+ socklen_t salen;
+
+ 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);
+ }
- 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);
- }
+ if ((err = getnameinfo(&sa.sa, salen,
+ host, sizeof(host),
+ NULL, 0,
+ NI_NUMERICHOST | NI_NUMERICSERV)) != 0) {
+ ERROR("Cannot convert socket address to string: %s",
+ gai_strerror(err));
+ continue;
+ }
+ } while (false);
- if ((err = getnameinfo(&sa.sa, salen,
- host, sizeof(host),
- NULL, 0,
- NI_NUMERICHOST | NI_NUMERICSERV)) != 0) {
- ERROR("Cannot convert socket address to string: %s",
- gai_strerror(err));
- continue;
- }
+ do {
+ struct addrinfo hints;
- hints = *pai;
- hints.ai_flags = AI_NUMERICHOST;
- hints.ai_family = af;
+ hints = *pai;
+ hints.ai_flags = AI_NUMERICHOST;
+ hints.ai_family = af;
- if (getaddrinfo(host, NULL, &hints, &res0)) {
- addrList++;
- continue;
- }
+ if (getaddrinfo(host, NULL, &hints, &res0)) {
+ addrList++;
+ continue;
+ }
+ } while (false);
for (res = res0; res; res = res->ai_next)
res->ai_flags = pai->ai_flags;
--
2.41.0On Wed, Aug 30, 2023 at 13:59:21 +0200, Peter Krempa wrote:
> 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>
> ---
> tools/nss/libvirt_nss.c | 97 +++++++++++++++++++++++------------------
> 1 file changed, 54 insertions(+), 43 deletions(-)
>
> diff --git a/tools/nss/libvirt_nss.c b/tools/nss/libvirt_nss.c
> index 37720bf4ae..dff3c034bf 100644
> --- a/tools/nss/libvirt_nss.c
> +++ b/tools/nss/libvirt_nss.c
[...]
> - hints = *pai;
> - hints.ai_flags = AI_NUMERICHOST;
> - hints.ai_family = af;
> + hints = *pai;
> + hints.ai_flags = AI_NUMERICHOST;
> + hints.ai_family = af;
>
> - if (getaddrinfo(host, NULL, &hints, &res0)) {
> - addrList++;
> - continue;
Ehh, self-NACK ...
> - }
> + if (getaddrinfo(host, NULL, &hints, &res0)) {
> + addrList++;
> + continue;
> + }
> + } while (false);
>
> for (res = res0; res; res = res->ai_next)
> res->ai_flags = pai->ai_flags;
> --
> 2.41.0
>
On Wed, Aug 30, 2023 at 2:21 PM Peter Krempa <pkrempa@redhat.com> wrote:
> On Wed, Aug 30, 2023 at 13:59:21 +0200, Peter Krempa wrote:
> > 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>
> > ---
> > tools/nss/libvirt_nss.c | 97 +++++++++++++++++++++++------------------
> > 1 file changed, 54 insertions(+), 43 deletions(-)
> >
> > diff --git a/tools/nss/libvirt_nss.c b/tools/nss/libvirt_nss.c
> > index 37720bf4ae..dff3c034bf 100644
> > --- a/tools/nss/libvirt_nss.c
> > +++ b/tools/nss/libvirt_nss.c
>
> [...]
>
> > - hints = *pai;
> > - hints.ai_flags = AI_NUMERICHOST;
> > - hints.ai_family = af;
> > + hints = *pai;
> > + hints.ai_flags = AI_NUMERICHOST;
> > + hints.ai_family = af;
> >
> > - if (getaddrinfo(host, NULL, &hints, &res0)) {
> > - addrList++;
> > - continue;
>
> Ehh, self-NACK ...
Apart from moving these two continue into loops...
>
>
> > - }
> > + if (getaddrinfo(host, NULL, &hints, &res0)) {
> > + addrList++;
> > + continue;
> > + }
> > + } while (false);
> >
> > for (res = res0; res; res = res->ai_next)
> > res->ai_flags = pai->ai_flags;
> > --
> > 2.41.0
> >
>
>
Reviewed-by: Kristina Hanicova <khanicov@redhat.com>
Kristina
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>
---
v2: Moved two error checks containing a 'continue' out of the 'do-while'
loop blocks
New pipeline:
https://gitlab.com/pipo.sk/libvirt/-/pipelines/986529301
tools/nss/libvirt_nss.c | 87 ++++++++++++++++++++++++-----------------
1 file changed, 51 insertions(+), 36 deletions(-)
diff --git a/tools/nss/libvirt_nss.c b/tools/nss/libvirt_nss.c
index 37720bf4ae..ff6ea1d373 100644
--- a/tools/nss/libvirt_nss.c
+++ b/tools/nss/libvirt_nss.c
@@ -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;
+
+ do {
+ union {
+ struct sockaddr sa;
+ struct sockaddr_in sin;
+ struct sockaddr_in6 sin6;
+ } sa = { 0 };
+ socklen_t salen;
+
+ 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);
+ }
- 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 = getnameinfo(&sa.sa, salen,
- host, sizeof(host),
- NULL, 0,
- NI_NUMERICHOST | NI_NUMERICSERV)) != 0) {
+ 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;
+
+ hints = *pai;
+ hints.ai_flags = AI_NUMERICHOST;
+ hints.ai_family = af;
+
+ err = getaddrinfo(host, NULL, &hints, &res0);
+ } while (false);
- if (getaddrinfo(host, NULL, &hints, &res0)) {
+ if (err != 0) {
addrList++;
continue;
}
--
2.41.0On Wed, Aug 30, 2023 at 3:17 PM Peter Krempa <pkrempa@redhat.com> wrote: > 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> > --- > > v2: Moved two error checks containing a 'continue' out of the 'do-while' > loop blocks > > New pipeline: > https://gitlab.com/pipo.sk/libvirt/-/pipelines/986529301 > > > tools/nss/libvirt_nss.c | 87 ++++++++++++++++++++++++----------------- > 1 file changed, 51 insertions(+), 36 deletions(-) > Reviewed-by: Kristina Hanicova <khanicov@redhat.com> Kristina
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