| Message ID | 20211111153354.18807-6-rvkagan@yandex-team.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vhost: stick to -errno error return convention | expand |
On 11/11/21 16:33, Roman Kagan wrote: > Fix the (hypothetical) potential problem when the value parsed out of > the vhost module parameter in sysfs overflows the return value from > vhost_kernel_memslots_limit. > > Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru> > --- > hw/virtio/vhost-backend.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c > index b65f8f7e97..44f7dbb243 100644 > --- a/hw/virtio/vhost-backend.c > +++ b/hw/virtio/vhost-backend.c > @@ -58,7 +58,7 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev) > if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions", > &s, NULL, NULL)) { > uint64_t val = g_ascii_strtoull(s, NULL, 10); Would using qemu_strtou64() simplify this? > - if (!((val == G_MAXUINT64 || !val) && errno)) { > + if (val < INT_MAX && val > 0) { > g_free(s); > return val; > } >
On Thu, Nov 11, 2021 at 06:59:43PM +0100, Philippe Mathieu-Daudé wrote: > On 11/11/21 16:33, Roman Kagan wrote: > > Fix the (hypothetical) potential problem when the value parsed out of > > the vhost module parameter in sysfs overflows the return value from > > vhost_kernel_memslots_limit. > > > > Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru> > > --- > > hw/virtio/vhost-backend.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c > > index b65f8f7e97..44f7dbb243 100644 > > --- a/hw/virtio/vhost-backend.c > > +++ b/hw/virtio/vhost-backend.c > > @@ -58,7 +58,7 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev) > > if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions", > > &s, NULL, NULL)) { > > uint64_t val = g_ascii_strtoull(s, NULL, 10); > > Would using qemu_strtou64() simplify this? I'm afraid not. None of the existing strtoXX converting functions has the desired output range (0 < retval < INT_MAX), so the following condition will remain necessary anyway; then it doesn't seem to matter which particular parser is used to extract the value which is in the range, so I left the one that was already there to reduce churn. > > > - if (!((val == G_MAXUINT64 || !val) && errno)) { > > + if (val < INT_MAX && val > 0) { > > g_free(s); > > return val; > > } Thanks, Roman.
On Fri, Nov 12, 2021 at 10:46:46AM +0300, Roman Kagan wrote: > On Thu, Nov 11, 2021 at 06:59:43PM +0100, Philippe Mathieu-Daudé wrote: > > On 11/11/21 16:33, Roman Kagan wrote: > > > Fix the (hypothetical) potential problem when the value parsed out of > > > the vhost module parameter in sysfs overflows the return value from > > > vhost_kernel_memslots_limit. > > > > > > Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru> > > > --- > > > hw/virtio/vhost-backend.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c > > > index b65f8f7e97..44f7dbb243 100644 > > > --- a/hw/virtio/vhost-backend.c > > > +++ b/hw/virtio/vhost-backend.c > > > @@ -58,7 +58,7 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev) > > > if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions", > > > &s, NULL, NULL)) { > > > uint64_t val = g_ascii_strtoull(s, NULL, 10); > > > > Would using qemu_strtou64() simplify this? > > I'm afraid not. None of the existing strtoXX converting functions has > the desired output range (0 < retval < INT_MAX), so the following > condition will remain necessary anyway; then it doesn't seem to matter > which particular parser is used to extract the value which is in the > range, so I left the one that was already there to reduce churn. If qemu_strtou64() can't handle all values in (0 < retval < INT_MAX) isn't that a bug in qemu_strtou64 ? Regards, Daniel
On Fri, Nov 12, 2021 at 09:56:17AM +0000, Daniel P. Berrangé wrote: > On Fri, Nov 12, 2021 at 10:46:46AM +0300, Roman Kagan wrote: > > On Thu, Nov 11, 2021 at 06:59:43PM +0100, Philippe Mathieu-Daudé wrote: > > > On 11/11/21 16:33, Roman Kagan wrote: > > > > Fix the (hypothetical) potential problem when the value parsed out of > > > > the vhost module parameter in sysfs overflows the return value from > > > > vhost_kernel_memslots_limit. > > > > > > > > Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru> > > > > --- > > > > hw/virtio/vhost-backend.c | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c > > > > index b65f8f7e97..44f7dbb243 100644 > > > > --- a/hw/virtio/vhost-backend.c > > > > +++ b/hw/virtio/vhost-backend.c > > > > @@ -58,7 +58,7 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev) > > > > if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions", > > > > &s, NULL, NULL)) { > > > > uint64_t val = g_ascii_strtoull(s, NULL, 10); > > > > > > Would using qemu_strtou64() simplify this? > > > > I'm afraid not. None of the existing strtoXX converting functions has > > the desired output range (0 < retval < INT_MAX), so the following > > condition will remain necessary anyway; then it doesn't seem to matter > > which particular parser is used to extract the value which is in the > > range, so I left the one that was already there to reduce churn. > > If qemu_strtou64() can't handle all values in (0 < retval < INT_MAX) > isn't that a bug in qemu_strtou64 ? I must have been unclear. It sure can handle all values in this range; the point is that the range check after it would still be needed, so switching from g_ascii_strtoull to qemu_strtoXX saves nothing, therefore I left it as it was. Thanks, Roman.
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c index b65f8f7e97..44f7dbb243 100644 --- a/hw/virtio/vhost-backend.c +++ b/hw/virtio/vhost-backend.c @@ -58,7 +58,7 @@ static int vhost_kernel_memslots_limit(struct vhost_dev *dev) if (g_file_get_contents("/sys/module/vhost/parameters/max_mem_regions", &s, NULL, NULL)) { uint64_t val = g_ascii_strtoull(s, NULL, 10); - if (!((val == G_MAXUINT64 || !val) && errno)) { + if (val < INT_MAX && val > 0) { g_free(s); return val; }
Fix the (hypothetical) potential problem when the value parsed out of the vhost module parameter in sysfs overflows the return value from vhost_kernel_memslots_limit. Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru> --- hw/virtio/vhost-backend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)