[PULL,1/1] block/nvme: fix Coverity reports
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Message ID 20180301075428.17320-2-famz@redhat.com
State New
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  • [PULL,1/1] block/nvme: fix Coverity reports
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Commit Message

Fam Zheng March 1, 2018, 7:54 a.m. UTC
From: Paolo Bonzini <pbonzini@redhat.com>

1) string not null terminated in sysfs_find_group_file

2) NULL pointer dereference and dead local variable in nvme_init.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>

Message-Id: <20180213015240.9352-1-famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/nvme.c        | 10 +++++++---
 util/vfio-helpers.c |  2 +-
 2 files changed, 8 insertions(+), 4 deletions(-)

Comments

Peter Maydell May 18, 2018, 6:01 p.m. UTC | #1
On 1 March 2018 at 07:54, Fam Zheng <famz@redhat.com> wrote:
> From: Paolo Bonzini <pbonzini@redhat.com>
>
> 1) string not null terminated in sysfs_find_group_file
>
> 2) NULL pointer dereference and dead local variable in nvme_init.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Fam Zheng <famz@redhat.com>
>
> Message-Id: <20180213015240.9352-1-famz@redhat.com>
> Signed-off-by: Fam Zheng <famz@redhat.com>

Hi. It looks like Coverity still doesn't like the error-exit
handling in nvme_init() (CID 1385847):

> ---
>  block/nvme.c        | 10 +++++++---
>  util/vfio-helpers.c |  2 +-
>  2 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/block/nvme.c b/block/nvme.c
> index 10bffbbf2f..75078022f6 100644
> --- a/block/nvme.c
> +++ b/block/nvme.c
> @@ -645,7 +645,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
>      aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
>                             false, nvme_handle_event, nvme_poll_cb);
>
> -    nvme_identify(bs, namespace, errp);
> +    nvme_identify(bs, namespace, &local_err);
>      if (local_err) {
>          error_propagate(errp, local_err);
>          ret = -EIO;
> @@ -666,8 +666,12 @@ fail_queue:
>      nvme_free_queue_pair(bs, s->queues[0]);
>  fail:
>      g_free(s->queues);
> -    qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
> -    qemu_vfio_close(s->vfio);
> +    if (s->regs) {
> +        qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);

We can get here with s->vfio being NULL and s->regs being
uninitialized, but qemu_vfio_pci_unmap_bar() will unconditionally
dereference s->vfio.

If you want to write the error path like this I think you need
to initialize s->regs = NULL before we do the qemu_vfio_open_pci()
call and error-check.

> +    }
> +    if (s->vfio) {
> +        qemu_vfio_close(s->vfio);
> +    }
>      event_notifier_cleanup(&s->irq_notifier);
>      return ret;
>  }

thanks
-- PMM
Fam Zheng May 21, 2018, 6:21 a.m. UTC | #2
On Fri, 05/18 19:01, Peter Maydell wrote:
> On 1 March 2018 at 07:54, Fam Zheng <famz@redhat.com> wrote:
> > From: Paolo Bonzini <pbonzini@redhat.com>
> >
> > 1) string not null terminated in sysfs_find_group_file
> >
> > 2) NULL pointer dereference and dead local variable in nvme_init.
> >
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> >
> > Message-Id: <20180213015240.9352-1-famz@redhat.com>
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> 
> Hi. It looks like Coverity still doesn't like the error-exit
> handling in nvme_init() (CID 1385847):
> 
> > ---
> >  block/nvme.c        | 10 +++++++---
> >  util/vfio-helpers.c |  2 +-
> >  2 files changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/block/nvme.c b/block/nvme.c
> > index 10bffbbf2f..75078022f6 100644
> > --- a/block/nvme.c
> > +++ b/block/nvme.c
> > @@ -645,7 +645,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
> >      aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
> >                             false, nvme_handle_event, nvme_poll_cb);
> >
> > -    nvme_identify(bs, namespace, errp);
> > +    nvme_identify(bs, namespace, &local_err);
> >      if (local_err) {
> >          error_propagate(errp, local_err);
> >          ret = -EIO;
> > @@ -666,8 +666,12 @@ fail_queue:
> >      nvme_free_queue_pair(bs, s->queues[0]);
> >  fail:
> >      g_free(s->queues);
> > -    qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
> > -    qemu_vfio_close(s->vfio);
> > +    if (s->regs) {
> > +        qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
> 
> We can get here with s->vfio being NULL and s->regs being
> uninitialized, but qemu_vfio_pci_unmap_bar() will unconditionally
> dereference s->vfio.
> 
> If you want to write the error path like this I think you need
> to initialize s->regs = NULL before we do the qemu_vfio_open_pci()
> call and error-check.

Block layer uses g_malloc0 to allocate *s, so we expect s->regs is NULL to begin
with. But I can send a patch to explicitly initialize it to NULL to make the
code simpler to reason.

Fam

> 
> > +    }
> > +    if (s->vfio) {
> > +        qemu_vfio_close(s->vfio);
> > +    }
> >      event_notifier_cleanup(&s->irq_notifier);
> >      return ret;
> >  }
> 
> thanks
> -- PMM

Patch
diff mbox series

diff --git a/block/nvme.c b/block/nvme.c
index 10bffbbf2f..75078022f6 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -645,7 +645,7 @@  static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
                            false, nvme_handle_event, nvme_poll_cb);
 
-    nvme_identify(bs, namespace, errp);
+    nvme_identify(bs, namespace, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         ret = -EIO;
@@ -666,8 +666,12 @@  fail_queue:
     nvme_free_queue_pair(bs, s->queues[0]);
 fail:
     g_free(s->queues);
-    qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
-    qemu_vfio_close(s->vfio);
+    if (s->regs) {
+        qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
+    }
+    if (s->vfio) {
+        qemu_vfio_close(s->vfio);
+    }
     event_notifier_cleanup(&s->irq_notifier);
     return ret;
 }
diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c
index f478b68400..006674c916 100644
--- a/util/vfio-helpers.c
+++ b/util/vfio-helpers.c
@@ -104,7 +104,7 @@  static char *sysfs_find_group_file(const char *device, Error **errp)
     char *path = NULL;
 
     sysfs_link = g_strdup_printf("/sys/bus/pci/devices/%s/iommu_group", device);
-    sysfs_group = g_malloc(PATH_MAX);
+    sysfs_group = g_malloc0(PATH_MAX);
     if (readlink(sysfs_link, sysfs_group, PATH_MAX - 1) == -1) {
         error_setg_errno(errp, errno, "Failed to find iommu group sysfs path");
         goto out;