| Message ID | 20230808091849.505809-1-suhui@nfschina.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fanotify: avoid possible NULL dereference | expand |
On Tue, Aug 8, 2023 at 12:19 PM Su Hui <suhui@nfschina.com> wrote: > > smatch error: > fs/notify/fanotify/fanotify_user.c:462 copy_fid_info_to_user(): > we previously assumed 'fh' could be null (see line 421) > > Fixes: afc894c784c8 ("fanotify: Store fanotify handles differently") > Signed-off-by: Su Hui <suhui@nfschina.com>' Reviewed-by: Amir Goldstein <amir73il@gmail.com> > --- > fs/notify/fanotify/fanotify_user.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c > index f69c451018e3..5a5487ae2460 100644 > --- a/fs/notify/fanotify/fanotify_user.c > +++ b/fs/notify/fanotify/fanotify_user.c > @@ -459,12 +459,13 @@ static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, > if (WARN_ON_ONCE(len < sizeof(handle))) > return -EFAULT; > > - handle.handle_type = fh->type; > handle.handle_bytes = fh_len; > > /* Mangle handle_type for bad file_handle */ > if (!fh_len) > handle.handle_type = FILEID_INVALID; > + else > + handle.handle_type = fh->type; > > if (copy_to_user(buf, &handle, sizeof(handle))) > return -EFAULT; > -- > 2.30.2 >
On Thu 10-08-23 20:58:16, Amir Goldstein wrote: > On Tue, Aug 8, 2023 at 12:19 PM Su Hui <suhui@nfschina.com> wrote: > > > > smatch error: > > fs/notify/fanotify/fanotify_user.c:462 copy_fid_info_to_user(): > > we previously assumed 'fh' could be null (see line 421) > > > > Fixes: afc894c784c8 ("fanotify: Store fanotify handles differently") > > Signed-off-by: Su Hui <suhui@nfschina.com>' > > Reviewed-by: Amir Goldstein <amir73il@gmail.com> I'm sorry but this has somehow fallen through the cracks. > > diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c > > index f69c451018e3..5a5487ae2460 100644 > > --- a/fs/notify/fanotify/fanotify_user.c > > +++ b/fs/notify/fanotify/fanotify_user.c > > @@ -459,12 +459,13 @@ static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, > > if (WARN_ON_ONCE(len < sizeof(handle))) > > return -EFAULT; > > > > - handle.handle_type = fh->type; > > handle.handle_bytes = fh_len; Well, if passed 'fh' is NULL, we have problems later in the function anyway. E.g. in fanotify_fh_buf() a few lines below. So I think this needs a bit more work that just this small fixup... Honza > > > > /* Mangle handle_type for bad file_handle */ > > if (!fh_len) > > handle.handle_type = FILEID_INVALID; > > + else > > + handle.handle_type = fh->type; > > > > if (copy_to_user(buf, &handle, sizeof(handle))) > > return -EFAULT; > > -- > > 2.30.2 > >
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index f69c451018e3..5a5487ae2460 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -459,12 +459,13 @@ static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh, if (WARN_ON_ONCE(len < sizeof(handle))) return -EFAULT; - handle.handle_type = fh->type; handle.handle_bytes = fh_len; /* Mangle handle_type for bad file_handle */ if (!fh_len) handle.handle_type = FILEID_INVALID; + else + handle.handle_type = fh->type; if (copy_to_user(buf, &handle, sizeof(handle))) return -EFAULT;
smatch error: fs/notify/fanotify/fanotify_user.c:462 copy_fid_info_to_user(): we previously assumed 'fh' could be null (see line 421) Fixes: afc894c784c8 ("fanotify: Store fanotify handles differently") Signed-off-by: Su Hui <suhui@nfschina.com> --- fs/notify/fanotify/fanotify_user.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)