On 15.04.2019 11:21, Daniel P. Berrangé wrote:

On Fri, Apr 12, 2019 at 06:10:49PM +0200, Adrian Brzezinski wrote:

...

Failed new gnutls context allocations in virNetTLSContextNew function results in double free and segfault. Occasional memory leaks may also occur. You can read detailed description at:

https://bugzilla.redhat.com/show_bug.cgi?id=1699062

Signed-off-by: Adrian Brzezinski <redhat@adrb.pl> --- docs/news.xml | 10 ++++++++++ src/rpc/virnettlscontext.c | 6 ++++-- 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/docs/news.xml b/docs/news.xml index 21807f2..f6157ec 100644 --- a/docs/news.xml +++ b/docs/news.xml @@ -350,6 +350,16 @@ <section title="Bug fixes"> <change> <summary> + rpc: Segfaults and memory leak in virNetTLSContextNew function + </summary> + <description> + Failed new gnutls context allocations in virNetTLSContextNew function + results in double free and segfault. Occasional memory leaks may also + occur. + </description> + </change> + <change> + <summary> qemu: Use CAP_DAC_OVERRIDE during QEMU capabilities probing </summary> <description> diff --git a/src/rpc/virnettlscontext.c b/src/rpc/virnettlscontext.c index 72e9ed9..8f6ec8f 100644 --- a/src/rpc/virnettlscontext.c +++ b/src/rpc/virnettlscontext.c @@ -703,14 +703,14 @@ static virNetTLSContextPtr virNetTLSContextNew(const char *cacert, return NULL;

if (VIR_STRDUP(ctxt->priority, priority) < 0) - goto error; + goto ctxt_init_error;

err = gnutls_certificate_allocate_credentials(&ctxt->x509cred); if (err) { virReportError(VIR_ERR_SYSTEM_ERROR, _("Unable to allocate x509 credentials: %s"), gnutls_strerror(err)); - goto error; + goto ctxt_init_error; }

if (sanityCheckCert && @@ -759,6 +759,8 @@ static virNetTLSContextPtr virNetTLSContextNew(const char *cacert, if (isServer) gnutls_dh_params_deinit(ctxt->dhParams); gnutls_certificate_free_credentials(ctxt->x509cred); + ctxt_init_error:

Having multiple label targets is not an attractive pattern. The core problem here is that gnutls_certificate_free_credentials will unconditionally dereference the credentials struct without checking if it is NULL. We can avoid this by just adding a check

if (ctxt->x509cred) gnutls_certificate_free_credentials(ctxt->x509cred);

Please read gdb session from bugzilla. What really failed is tlist allocation in gnutls_certificate_allocate_credentials, so ctxt->x509cred isn't NULL. But I got your point.

...

+ if (ctxt->priority) VIR_FREE(ctxt->priority); VIR_FREE(ctxt); return NULL; }

Regards, Daniel

-- Adrian Brzeziński Technical Care Center EO Networks S.A. ul. Jagiellońska 78, 03-301 Warszawa tel: (022) 532-15-30, fax: (022) 532-15-31 e-mail : adrian.brzezinski@eo.pl NIP : 5272604418, REGON : 141905973 Sąd Rejonowy dla m.st.. Warszawy w Warszawie XII Wydział Gospodarczy Krajowego Rejestru Sądowego, KRS: 0000332547, Kapitał zakładowy i kapitał wpłacony : 205 937,90 złotych. Ten dokument zawiera informacje poufne, które mogą być również objęte tajemnicą handlową lub służbową. Jest on przeznaczony do wyłącznego użytku adresata. Jeśli nie są Państwo jego adresatem lub jeśli otrzymaliście Państwo ten dokument omyłkowo, to wszelkie rozpowszechnianie, dystrybucja, reprodukcja, kopiowanie, publikacja lub wykorzystanie tego dokumentu czy też zawartych w nim informacji jest zabronione. Jeśli otrzymaliście Państwo tę wiadomość przez pomyłkę, prosimy o bezzwłoczne skontaktowanie się z nami oraz usunięcie tej wiadomości z Państwa komputera. This message may contain confidential and/or privileged information and is intended solely for the use of the individual or entity to whom is addressed. If you are not the intended recipient, then any disclosure, copying, distribution or any other action in reliance upon is expressly prohibited and may be unlawful. In this case, please advise the sender by replying and deleting this message.

Failed new gnutls context allocations in virNetTLSContextNew function results in double free and segfault. Occasional memory leaks may also occur. Signed-off-by: Adrian Brzezinski <redhat@adrb.pl> --- src/rpc/virnettlscontext.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/src/rpc/virnettlscontext.c b/src/rpc/virnettlscontext.c index 72e9ed9..7b5d578 100644 --- a/src/rpc/virnettlscontext.c +++ b/src/rpc/virnettlscontext.c @@ -707,6 +707,12 @@ static virNetTLSContextPtr virNetTLSContextNew(const char *cacert, err = gnutls_certificate_allocate_credentials(&ctxt->x509cred); if (err) { + /* gnutls_certificate_credentials_t is complex structure with multiple + * internal memory allocatons that can go wrong, so make sure that + * reference is NULL. + */ + ctxt->x509cred = NULL; + virReportError(VIR_ERR_SYSTEM_ERROR, _("Unable to allocate x509 credentials: %s"), gnutls_strerror(err)); @@ -758,7 +764,9 @@ static virNetTLSContextPtr virNetTLSContextNew(const char *cacert, error: if (isServer) gnutls_dh_params_deinit(ctxt->dhParams); - gnutls_certificate_free_credentials(ctxt->x509cred); + if (ctxt->x509cred) + gnutls_certificate_free_credentials(ctxt->x509cred); + VIR_FREE(ctxt->priority); VIR_FREE(ctxt); return NULL; } -- 1.8.3.1

Signed-off-by: Adrian Brzezinski <redhat@adrb.pl> --- docs/news.xml | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/docs/news.xml b/docs/news.xml index 86c7734..9338381 100644 --- a/docs/news.xml +++ b/docs/news.xml @@ -51,6 +51,16 @@ </change> </section> <section title="Bug fixes"> + <change> + <summary> + rpc: cleanup in virNetTLSContextNew + </summary> + <description> + Failed new gnutls context allocations in virNetTLSContextNew + function results in double free and segfault. Occasional memory + leaks may also occur. + </description> + </change> </section> </release> <release version="v5.2.0" date="2019-04-03"> -- 1.8.3.1