tools/virtiofsd/passthrough_ll.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
On success, the fdopendir() call closes fd. Later on the error
path we try to close an already-closed fd. This can lead to
use-after-free. Fix by only closing the fd if the fdopendir()
call failed.
Cc: qemu-stable@nongnu.org
Fixes: 7c6b66027 (Import passthrough_ll from libfuse fuse-3.8.0)
Reported-by: Coverity (CID 1421933 USE_AFTER_FREE)
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
tools/virtiofsd/passthrough_ll.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 4f259aac70..4c35c95b25 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -1520,8 +1520,7 @@ out_err:
if (d) {
if (d->dp) {
closedir(d->dp);
- }
- if (fd != -1) {
+ } else if (fd != -1) {
close(fd);
}
free(d);
--
2.21.1
On 3/21/20 1:06 PM, Philippe Mathieu-Daudé wrote: > On success, the fdopendir() call closes fd. Later on the error > path we try to close an already-closed fd. This can lead to > use-after-free. Fix by only closing the fd if the fdopendir() > call failed. > > Cc: qemu-stable@nongnu.org > Fixes: 7c6b66027 (Import passthrough_ll from libfuse fuse-3.8.0) libfuse is correct, the bug was introduced in commit b39bce121b, so: Fixes: b39bce121b (add dirp_map to hide lo_dirp pointers) > Reported-by: Coverity (CID 1421933 USE_AFTER_FREE) > Suggested-by: Peter Maydell <peter.maydell@linaro.org> > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > --- > tools/virtiofsd/passthrough_ll.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c > index 4f259aac70..4c35c95b25 100644 > --- a/tools/virtiofsd/passthrough_ll.c > +++ b/tools/virtiofsd/passthrough_ll.c > @@ -1520,8 +1520,7 @@ out_err: > if (d) { > if (d->dp) { > closedir(d->dp); > - } > - if (fd != -1) { > + } else if (fd != -1) { > close(fd); > } > free(d); >
* Philippe Mathieu-Daudé (philmd@redhat.com) wrote: > On 3/21/20 1:06 PM, Philippe Mathieu-Daudé wrote: > > On success, the fdopendir() call closes fd. Later on the error > > path we try to close an already-closed fd. This can lead to > > use-after-free. Fix by only closing the fd if the fdopendir() > > call failed. > > > > Cc: qemu-stable@nongnu.org > > Fixes: 7c6b66027 (Import passthrough_ll from libfuse fuse-3.8.0) > > libfuse is correct, the bug was introduced in commit b39bce121b, so: > > Fixes: b39bce121b (add dirp_map to hide lo_dirp pointers) Queued with that tweak > > Reported-by: Coverity (CID 1421933 USE_AFTER_FREE) > > Suggested-by: Peter Maydell <peter.maydell@linaro.org> > > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > > --- > > tools/virtiofsd/passthrough_ll.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c > > index 4f259aac70..4c35c95b25 100644 > > --- a/tools/virtiofsd/passthrough_ll.c > > +++ b/tools/virtiofsd/passthrough_ll.c > > @@ -1520,8 +1520,7 @@ out_err: > > if (d) { > > if (d->dp) { > > closedir(d->dp); > > - } > > - if (fd != -1) { > > + } else if (fd != -1) { > > close(fd); > > } > > free(d); > > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Sat, Mar 21, 2020 at 01:06:54PM +0100, Philippe Mathieu-Daudé wrote: > On success, the fdopendir() call closes fd. Later on the error > path we try to close an already-closed fd. This can lead to > use-after-free. Fix by only closing the fd if the fdopendir() > call failed. > > Cc: qemu-stable@nongnu.org > Fixes: 7c6b66027 (Import passthrough_ll from libfuse fuse-3.8.0) > Reported-by: Coverity (CID 1421933 USE_AFTER_FREE) > Suggested-by: Peter Maydell <peter.maydell@linaro.org> > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > --- > tools/virtiofsd/passthrough_ll.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) Thanks! Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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