$subj:
util: Fix cgroup processing NULL pointer dereferencing
On 9/26/18 11:53 AM, Marc Hartmayer wrote:
> When virCgroupEnableMissingControllers fails it's possible that *group
> is still set to NULL. Therefore let's add a guard and an attribute for
> this.
Prefix paragraph with rather than at the bottom "Fixes:".
Introduced by commit 1602aa28f,
>
> [#0] virCgroupRemove(group=0x0)
> [#1] virCgroupNewMachineSystemd
> [#2] virCgroupNewMachine
> [#3] qemuInitCgroup
> [#4] qemuSetupCgroup
> [#5] qemuProcessLaunch
> [#6] qemuProcessStart
> [#7] qemuDomainObjStart
> [#8] qemuDomainCreateWithFlags
> [#9] qemuDomainCreate
> ...
>
> Fixes: 1602aa28f820ada66f707cef3e536e8572fbda1e
I think it's safe to remove the stack trace...
> Reviewed-by: Boris Fiuczynski <fiuczy@xxxxxxxxxxxxx>
> Reviewed-by: Bjoern Walk <bwalk@xxxxxxxxxxxxx>
> Signed-off-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx>
> ---
> src/util/vircgroup.c | 3 ++-
> src/util/vircgroup.h | 3 ++-
> 2 files changed, 4 insertions(+), 2 deletions(-)
While this patch is correct to remove the NULL deref, there "may" be a
problem with the patch that introduced this. Rather than usurp this
thread, I'll respond to the other one and see where it takes us.
John
>
> diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
> index 23957c82c7fa..06e1d158febb 100644
> --- a/src/util/vircgroup.c
> +++ b/src/util/vircgroup.c
> @@ -1104,7 +1104,8 @@ virCgroupNewMachineSystemd(const char *name,
>
> error:
> saved = virSaveLastError();
> - virCgroupRemove(*group);
> + if (*group)
> + virCgroupRemove(*group);
> virCgroupFree(group);
> if (saved) {
> virSetError(saved);
> diff --git a/src/util/vircgroup.h b/src/util/vircgroup.h
> index 1f676f21c380..9e1ae3706b1e 100644
> --- a/src/util/vircgroup.h
> +++ b/src/util/vircgroup.h
> @@ -268,7 +268,8 @@ int virCgroupGetCpusetMemoryMigrate(virCgroupPtr group, bool *migrate);
> int virCgroupSetCpusetCpus(virCgroupPtr group, const char *cpus);
> int virCgroupGetCpusetCpus(virCgroupPtr group, char **cpus);
>
> -int virCgroupRemove(virCgroupPtr group);
> +int virCgroupRemove(virCgroupPtr group)
> + ATTRIBUTE_NONNULL(1);
FWIW: This only helps if someone tried to call virCgroupRemove(NULL); it
doesn't help if the parameter itself is NULL. One could add a "if
(!group) return 0" to virCgroupRemove to avoid.
>
> int virCgroupKillRecursive(virCgroupPtr group, int signum);
> int virCgroupKillPainfully(virCgroupPtr group);
>
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list
