[Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Jeff Cody]

The function qemu_strtoul() reads 'unsigned long' sized data,
which is larger than uint32_t on 64-bit machines.

Even though the snap_id field in the header is 32-bits, we must
accomodate the full size in qemu_strtoul().

This patch also adds more meaningful error handling to the
qemu_strtoul() call, and subsequent results.

Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
---
 block/sheepdog.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/block/sheepdog.c b/block/sheepdog.c
index 8739acc..87f0027 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -2543,7 +2543,7 @@ static int sd_snapshot_delete(BlockDriverState *bs,
                               const char *name,
                               Error **errp)
 {
-    uint32_t snap_id = 0;
+    unsigned long snap_id = 0;
     char snap_tag[SD_MAX_VDI_TAG_LEN];
     Error *local_err = NULL;
     int fd, ret;
@@ -2565,12 +2565,15 @@ static int sd_snapshot_delete(BlockDriverState *bs,
     memset(buf, 0, sizeof(buf));
     memset(snap_tag, 0, sizeof(snap_tag));
     pstrcpy(buf, SD_MAX_VDI_LEN, s->name);
-    if (qemu_strtoul(snapshot_id, NULL, 10, (unsigned long *)&snap_id)) {
-        return -1;
+    ret = qemu_strtoul(snapshot_id, NULL, 10, &snap_id);
+    if (ret || snap_id > UINT32_MAX) {
+        error_setg(errp, "Invalid snapshot ID: %s",
+                         snapshot_id ? snapshot_id : "<null>");
+        return -EINVAL;
     }
 
     if (snap_id) {
-        hdr.snapid = snap_id;
+        hdr.snapid = (uint32_t) snap_id;
     } else {
         pstrcpy(snap_tag, sizeof(snap_tag), snapshot_id);
         pstrcpy(buf + SD_MAX_VDI_LEN, SD_MAX_VDI_TAG_LEN, snap_tag);
-- 
1.9.3

Re: [Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Max Reitz]

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On 02.03.2016 17:24, Jeff Cody wrote:
> The function qemu_strtoul() reads 'unsigned long' sized data,
> which is larger than uint32_t on 64-bit machines.
> 
> Even though the snap_id field in the header is 32-bits, we must
> accomodate the full size in qemu_strtoul().
> 
> This patch also adds more meaningful error handling to the
> qemu_strtoul() call, and subsequent results.
> 
> Reported-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Jeff Cody <jcody@redhat.com>
> ---
>  block/sheepdog.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/block/sheepdog.c b/block/sheepdog.c
> index 8739acc..87f0027 100644
> --- a/block/sheepdog.c
> +++ b/block/sheepdog.c
> @@ -2543,7 +2543,7 @@ static int sd_snapshot_delete(BlockDriverState *bs,
>                                const char *name,
>                                Error **errp)
>  {
> -    uint32_t snap_id = 0;
> +    unsigned long snap_id = 0;
>      char snap_tag[SD_MAX_VDI_TAG_LEN];
>      Error *local_err = NULL;
>      int fd, ret;
> @@ -2565,12 +2565,15 @@ static int sd_snapshot_delete(BlockDriverState *bs,
>      memset(buf, 0, sizeof(buf));
>      memset(snap_tag, 0, sizeof(snap_tag));
>      pstrcpy(buf, SD_MAX_VDI_LEN, s->name);
> -    if (qemu_strtoul(snapshot_id, NULL, 10, (unsigned long *)&snap_id)) {
> -        return -1;
> +    ret = qemu_strtoul(snapshot_id, NULL, 10, &snap_id);
> +    if (ret || snap_id > UINT32_MAX) {
> +        error_setg(errp, "Invalid snapshot ID: %s",
> +                         snapshot_id ? snapshot_id : "<null>");
> +        return -EINVAL;
>      }
>  
>      if (snap_id) {
> -        hdr.snapid = snap_id;
> +        hdr.snapid = (uint32_t) snap_id;

BTW, not so sure why you are doing an explicit cast to uint32_t here but
not in the call to find_vdi_name() below. But I'll spare you a v4 :-)

Reviewed-by: Max Reitz <mreitz@redhat.com>

>      } else {
>          pstrcpy(snap_tag, sizeof(snap_tag), snapshot_id);
>          pstrcpy(buf + SD_MAX_VDI_LEN, SD_MAX_VDI_TAG_LEN, snap_tag);
> 



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Re: [Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Eric Blake]

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On 03/02/2016 09:24 AM, Jeff Cody wrote:
> The function qemu_strtoul() reads 'unsigned long' sized data,
> which is larger than uint32_t on 64-bit machines.
> 
> Even though the snap_id field in the header is 32-bits, we must
> accomodate the full size in qemu_strtoul().

s/accomodate/accommodate/

Someday, it might be nice to write a qemu_strtoi() and qemu_strtoui()
that provide a guaranteed 32-bit result, rather than a
platform-dependent width (we already have qemu_strto[u]ll() for 64-bit
results).  It's a bit tricky, since C doesn't provide a native parsing
to int, and the case for overflow detection is different on 32-bit
machines than on 64-bit machines (libvirt took a couple of tries before
getting something that worked correctly), but would probably be worth it
in the long run.

But that idea doesn't have to hold up this patch.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Max Reitz]

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On 02.03.2016 17:24, Jeff Cody wrote:
> The function qemu_strtoul() reads 'unsigned long' sized data,
> which is larger than uint32_t on 64-bit machines.
> 
> Even though the snap_id field in the header is 32-bits, we must
> accomodate the full size in qemu_strtoul().
> 
> This patch also adds more meaningful error handling to the
> qemu_strtoul() call, and subsequent results.
> 
> Reported-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Jeff Cody <jcody@redhat.com>
> ---
>  block/sheepdog.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)

Another problem with this function is that it doesn't always set errp on
error. Actually, this patch introduces the first instance where it does.

qemu-img will not print an error if errp is not set; it actually ignores
bdrv_snapshot_delete_by_id_or_name()'s return value. So this is a real
issue that should be fixed as well.

Max


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Re: [Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Jeff Cody]

On Wed, Mar 02, 2016 at 05:32:11PM +0100, Max Reitz wrote:
> On 02.03.2016 17:24, Jeff Cody wrote:
> > The function qemu_strtoul() reads 'unsigned long' sized data,
> > which is larger than uint32_t on 64-bit machines.
> > 
> > Even though the snap_id field in the header is 32-bits, we must
> > accomodate the full size in qemu_strtoul().
> > 
> > This patch also adds more meaningful error handling to the
> > qemu_strtoul() call, and subsequent results.
> > 
> > Reported-by: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Jeff Cody <jcody@redhat.com>
> > ---
> >  block/sheepdog.c | 11 +++++++----
> >  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> Another problem with this function is that it doesn't always set errp on
> error. Actually, this patch introduces the first instance where it does.
> 
> qemu-img will not print an error if errp is not set; it actually ignores
> bdrv_snapshot_delete_by_id_or_name()'s return value. So this is a real
> issue that should be fixed as well.
>

I'll (or perhaps one of the sheepdog maintainers?) will handle that in
subsequent patch(es).

Re: [Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Jeff Cody]

On Wed, Mar 02, 2016 at 09:30:45AM -0700, Eric Blake wrote:
> On 03/02/2016 09:24 AM, Jeff Cody wrote:
> > The function qemu_strtoul() reads 'unsigned long' sized data,
> > which is larger than uint32_t on 64-bit machines.
> > 
> > Even though the snap_id field in the header is 32-bits, we must
> > accomodate the full size in qemu_strtoul().
> 
> s/accomodate/accommodate/

Thanks, I'll fix that up when applying this patch to my block branch.

> 
> Someday, it might be nice to write a qemu_strtoi() and qemu_strtoui()
> that provide a guaranteed 32-bit result, rather than a
> platform-dependent width (we already have qemu_strto[u]ll() for 64-bit
> results).  It's a bit tricky, since C doesn't provide a native parsing
> to int, and the case for overflow detection is different on 32-bit
> machines than on 64-bit machines (libvirt took a couple of tries before
> getting something that worked correctly), but would probably be worth it
> in the long run.
> 
> But that idea doesn't have to hold up this patch.
> 
> -- 
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
> 

Re: [Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Hitoshi Mitake]

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On Thu, Mar 3, 2016 at 1:24 AM, Jeff Cody <jcody@redhat.com> wrote:

> The function qemu_strtoul() reads 'unsigned long' sized data,
> which is larger than uint32_t on 64-bit machines.
>
> Even though the snap_id field in the header is 32-bits, we must
> accomodate the full size in qemu_strtoul().
>
> This patch also adds more meaningful error handling to the
> qemu_strtoul() call, and subsequent results.
>
> Reported-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Jeff Cody <jcody@redhat.com>
> ---
>  block/sheepdog.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
>

Thanks a lot for your fix!

Reviewed-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>

Thanks,
Hitoshi


>
> diff --git a/block/sheepdog.c b/block/sheepdog.c
> index 8739acc..87f0027 100644
> --- a/block/sheepdog.c
> +++ b/block/sheepdog.c
> @@ -2543,7 +2543,7 @@ static int sd_snapshot_delete(BlockDriverState *bs,
>                                const char *name,
>                                Error **errp)
>  {
> -    uint32_t snap_id = 0;
> +    unsigned long snap_id = 0;
>      char snap_tag[SD_MAX_VDI_TAG_LEN];
>      Error *local_err = NULL;
>      int fd, ret;
> @@ -2565,12 +2565,15 @@ static int sd_snapshot_delete(BlockDriverState *bs,
>      memset(buf, 0, sizeof(buf));
>      memset(snap_tag, 0, sizeof(snap_tag));
>      pstrcpy(buf, SD_MAX_VDI_LEN, s->name);
> -    if (qemu_strtoul(snapshot_id, NULL, 10, (unsigned long *)&snap_id)) {
> -        return -1;
> +    ret = qemu_strtoul(snapshot_id, NULL, 10, &snap_id);
> +    if (ret || snap_id > UINT32_MAX) {
> +        error_setg(errp, "Invalid snapshot ID: %s",
> +                         snapshot_id ? snapshot_id : "<null>");
> +        return -EINVAL;
>      }
>
>      if (snap_id) {
> -        hdr.snapid = snap_id;
> +        hdr.snapid = (uint32_t) snap_id;
>      } else {
>          pstrcpy(snap_tag, sizeof(snap_tag), snapshot_id);
>          pstrcpy(buf + SD_MAX_VDI_LEN, SD_MAX_VDI_TAG_LEN, snap_tag);
> --
> 1.9.3
>
>
>

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Re: [Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Hitoshi Mitake]

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On Thu, Mar 3, 2016 at 1:36 AM, Jeff Cody <jcody@redhat.com> wrote:

> On Wed, Mar 02, 2016 at 05:32:11PM +0100, Max Reitz wrote:
> > On 02.03.2016 17:24, Jeff Cody wrote:
> > > The function qemu_strtoul() reads 'unsigned long' sized data,
> > > which is larger than uint32_t on 64-bit machines.
> > >
> > > Even though the snap_id field in the header is 32-bits, we must
> > > accomodate the full size in qemu_strtoul().
> > >
> > > This patch also adds more meaningful error handling to the
> > > qemu_strtoul() call, and subsequent results.
> > >
> > > Reported-by: Paolo Bonzini <pbonzini@redhat.com>
> > > Signed-off-by: Jeff Cody <jcody@redhat.com>
> > > ---
> > >  block/sheepdog.c | 11 +++++++----
> > >  1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > Another problem with this function is that it doesn't always set errp on
> > error. Actually, this patch introduces the first instance where it does.
> >
> > qemu-img will not print an error if errp is not set; it actually ignores
> > bdrv_snapshot_delete_by_id_or_name()'s return value. So this is a real
> > issue that should be fixed as well.
> >
>
> I'll (or perhaps one of the sheepdog maintainers?) will handle that in
> subsequent patch(es).
>

Thanks for your pointing. I didn't notice the problem when I posted the
patch. I'll fix it later.

Thanks,
Hitoshi

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Re: [Qemu-devel] [PATCH v3 1/1] block/sheepdog: fix argument passed to qemu_strtoul()

[Jeff Cody]

On Wed, Mar 02, 2016 at 11:24:42AM -0500, Jeff Cody wrote:
> The function qemu_strtoul() reads 'unsigned long' sized data,
> which is larger than uint32_t on 64-bit machines.
> 
> Even though the snap_id field in the header is 32-bits, we must
> accomodate the full size in qemu_strtoul().
> 
> This patch also adds more meaningful error handling to the
> qemu_strtoul() call, and subsequent results.
> 
> Reported-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Jeff Cody <jcody@redhat.com>
> ---
>  block/sheepdog.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/block/sheepdog.c b/block/sheepdog.c
> index 8739acc..87f0027 100644
> --- a/block/sheepdog.c
> +++ b/block/sheepdog.c
> @@ -2543,7 +2543,7 @@ static int sd_snapshot_delete(BlockDriverState *bs,
>                                const char *name,
>                                Error **errp)
>  {
> -    uint32_t snap_id = 0;
> +    unsigned long snap_id = 0;
>      char snap_tag[SD_MAX_VDI_TAG_LEN];
>      Error *local_err = NULL;
>      int fd, ret;
> @@ -2565,12 +2565,15 @@ static int sd_snapshot_delete(BlockDriverState *bs,
>      memset(buf, 0, sizeof(buf));
>      memset(snap_tag, 0, sizeof(snap_tag));
>      pstrcpy(buf, SD_MAX_VDI_LEN, s->name);
> -    if (qemu_strtoul(snapshot_id, NULL, 10, (unsigned long *)&snap_id)) {
> -        return -1;
> +    ret = qemu_strtoul(snapshot_id, NULL, 10, &snap_id);
> +    if (ret || snap_id > UINT32_MAX) {
> +        error_setg(errp, "Invalid snapshot ID: %s",
> +                         snapshot_id ? snapshot_id : "<null>");
> +        return -EINVAL;
>      }
>  
>      if (snap_id) {
> -        hdr.snapid = snap_id;
> +        hdr.snapid = (uint32_t) snap_id;
>      } else {
>          pstrcpy(snap_tag, sizeof(snap_tag), snapshot_id);
>          pstrcpy(buf + SD_MAX_VDI_LEN, SD_MAX_VDI_TAG_LEN, snap_tag);
> -- 
> 1.9.3
> 

Thanks,

Applied to my block branch:

git://github.com/codyprime/qemu-kvm-jtc.git block

-Jeff