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Message-ID: <bf3f21db-1825-ad43-4895-87843d822c49@huawei.com>
Date: Tue, 27 Oct 2020 17:21:34 +0800
From: Zhiqiang Liu <liuzhiqiang26@...wei.com>
To: <miklos@...redi.hu>, <mszeredi@...hat.com>
CC: linfeilong <linfeilong@...wei.com>,
<linux-fsdevel@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
lihaotian <lihaotian9@...wei.com>,
<fuse-devel@...ts.sourceforge.net>, <kschalk@...dia.com>,
<Nikolaus@...h.org>
Subject: Re: [PATCH] fuse: fix potential accessing NULL pointer problem in
fuse_send_init()
friendly ping...
On 2020/10/22 22:51, Zhiqiang Liu wrote:
>
> In fuse_send_init func, ia is allocated by calling kzalloc func, and
> we donot check whether ia is NULL before using it. Thus, if allocating
> ia fails, accessing NULL pointer problem will occur.
>
> Here, we will call process_init_reply func if ia is NULL.
>
> Fixes: 615047eff108 ("fuse: convert init to simple api")
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@...wei.com>
> Signed-off-by: Haotian Li <lihaotian9@...wei.com>
> ---
> fs/fuse/inode.c | 161 ++++++++++++++++++++++++++----------------------
> 1 file changed, 87 insertions(+), 74 deletions(-)
>
> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
> index 581329203d68..bb526d8cf5b0 100644
> --- a/fs/fuse/inode.c
> +++ b/fs/fuse/inode.c
> @@ -898,88 +898,97 @@ struct fuse_init_args {
> static void process_init_reply(struct fuse_conn *fc, struct fuse_args *args,
> int error)
> {
> - struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
> - struct fuse_init_out *arg = &ia->out;
> + struct fuse_init_args *ia;
> + struct fuse_init_out *arg;
> + unsigned long ra_pages;
>
> - if (error || arg->major != FUSE_KERNEL_VERSION)
> + if (!args) {
> fc->conn_error = 1;
> - else {
> - unsigned long ra_pages;
> + goto out;
> + }
>
> - process_init_limits(fc, arg);
> + ia = container_of(args, typeof(*ia), args);
> + arg = &ia->out;
> + if (error || arg->major != FUSE_KERNEL_VERSION) {
> + fc->conn_error = 1;
> + goto out_free_ia;
> + }
>
> - if (arg->minor >= 6) {
> - ra_pages = arg->max_readahead / PAGE_SIZE;
> - if (arg->flags & FUSE_ASYNC_READ)
> - fc->async_read = 1;
> - if (!(arg->flags & FUSE_POSIX_LOCKS))
> - fc->no_lock = 1;
> - if (arg->minor >= 17) {
> - if (!(arg->flags & FUSE_FLOCK_LOCKS))
> - fc->no_flock = 1;
> - } else {
> - if (!(arg->flags & FUSE_POSIX_LOCKS))
> - fc->no_flock = 1;
> - }
> - if (arg->flags & FUSE_ATOMIC_O_TRUNC)
> - fc->atomic_o_trunc = 1;
> - if (arg->minor >= 9) {
> - /* LOOKUP has dependency on proto version */
> - if (arg->flags & FUSE_EXPORT_SUPPORT)
> - fc->export_support = 1;
> - }
> - if (arg->flags & FUSE_BIG_WRITES)
> - fc->big_writes = 1;
> - if (arg->flags & FUSE_DONT_MASK)
> - fc->dont_mask = 1;
> - if (arg->flags & FUSE_AUTO_INVAL_DATA)
> - fc->auto_inval_data = 1;
> - else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
> - fc->explicit_inval_data = 1;
> - if (arg->flags & FUSE_DO_READDIRPLUS) {
> - fc->do_readdirplus = 1;
> - if (arg->flags & FUSE_READDIRPLUS_AUTO)
> - fc->readdirplus_auto = 1;
> - }
> - if (arg->flags & FUSE_ASYNC_DIO)
> - fc->async_dio = 1;
> - if (arg->flags & FUSE_WRITEBACK_CACHE)
> - fc->writeback_cache = 1;
> - if (arg->flags & FUSE_PARALLEL_DIROPS)
> - fc->parallel_dirops = 1;
> - if (arg->flags & FUSE_HANDLE_KILLPRIV)
> - fc->handle_killpriv = 1;
> - if (arg->time_gran && arg->time_gran <= 1000000000)
> - fc->sb->s_time_gran = arg->time_gran;
> - if ((arg->flags & FUSE_POSIX_ACL)) {
> - fc->default_permissions = 1;
> - fc->posix_acl = 1;
> - fc->sb->s_xattr = fuse_acl_xattr_handlers;
> - }
> - if (arg->flags & FUSE_CACHE_SYMLINKS)
> - fc->cache_symlinks = 1;
> - if (arg->flags & FUSE_ABORT_ERROR)
> - fc->abort_err = 1;
> - if (arg->flags & FUSE_MAX_PAGES) {
> - fc->max_pages =
> - min_t(unsigned int, FUSE_MAX_MAX_PAGES,
> - max_t(unsigned int, arg->max_pages, 1));
> - }
> - } else {
> - ra_pages = fc->max_read / PAGE_SIZE;
> + process_init_limits(fc, arg);
> +
> + if (arg->minor >= 6) {
> + ra_pages = arg->max_readahead / PAGE_SIZE;
> + if (arg->flags & FUSE_ASYNC_READ)
> + fc->async_read = 1;
> + if (!(arg->flags & FUSE_POSIX_LOCKS))
> fc->no_lock = 1;
> - fc->no_flock = 1;
> + if (arg->minor >= 17) {
> + if (!(arg->flags & FUSE_FLOCK_LOCKS))
> + fc->no_flock = 1;
> + } else {
> + if (!(arg->flags & FUSE_POSIX_LOCKS))
> + fc->no_flock = 1;
> }
> -
> - fc->sb->s_bdi->ra_pages =
> - min(fc->sb->s_bdi->ra_pages, ra_pages);
> - fc->minor = arg->minor;
> - fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
> - fc->max_write = max_t(unsigned, 4096, fc->max_write);
> - fc->conn_init = 1;
> + if (arg->flags & FUSE_ATOMIC_O_TRUNC)
> + fc->atomic_o_trunc = 1;
> + if (arg->minor >= 9) {
> + /* LOOKUP has dependency on proto version */
> + if (arg->flags & FUSE_EXPORT_SUPPORT)
> + fc->export_support = 1;
> + }
> + if (arg->flags & FUSE_BIG_WRITES)
> + fc->big_writes = 1;
> + if (arg->flags & FUSE_DONT_MASK)
> + fc->dont_mask = 1;
> + if (arg->flags & FUSE_AUTO_INVAL_DATA)
> + fc->auto_inval_data = 1;
> + else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
> + fc->explicit_inval_data = 1;
> + if (arg->flags & FUSE_DO_READDIRPLUS) {
> + fc->do_readdirplus = 1;
> + if (arg->flags & FUSE_READDIRPLUS_AUTO)
> + fc->readdirplus_auto = 1;
> + }
> + if (arg->flags & FUSE_ASYNC_DIO)
> + fc->async_dio = 1;
> + if (arg->flags & FUSE_WRITEBACK_CACHE)
> + fc->writeback_cache = 1;
> + if (arg->flags & FUSE_PARALLEL_DIROPS)
> + fc->parallel_dirops = 1;
> + if (arg->flags & FUSE_HANDLE_KILLPRIV)
> + fc->handle_killpriv = 1;
> + if (arg->time_gran && arg->time_gran <= 1000000000)
> + fc->sb->s_time_gran = arg->time_gran;
> + if ((arg->flags & FUSE_POSIX_ACL)) {
> + fc->default_permissions = 1;
> + fc->posix_acl = 1;
> + fc->sb->s_xattr = fuse_acl_xattr_handlers;
> + }
> + if (arg->flags & FUSE_CACHE_SYMLINKS)
> + fc->cache_symlinks = 1;
> + if (arg->flags & FUSE_ABORT_ERROR)
> + fc->abort_err = 1;
> + if (arg->flags & FUSE_MAX_PAGES) {
> + fc->max_pages =
> + min_t(unsigned int, FUSE_MAX_MAX_PAGES,
> + max_t(unsigned int, arg->max_pages, 1));
> + }
> + } else {
> + ra_pages = fc->max_read / PAGE_SIZE;
> + fc->no_lock = 1;
> + fc->no_flock = 1;
> }
> - kfree(ia);
>
> + fc->sb->s_bdi->ra_pages =
> + min(fc->sb->s_bdi->ra_pages, ra_pages);
> + fc->minor = arg->minor;
> + fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
> + fc->max_write = max_t(unsigned int, 4096, fc->max_write);
> + fc->conn_init = 1;
> +
> +out_free_ia:
> + kfree(ia);
> +out:
> fuse_set_initialized(fc);
> wake_up_all(&fc->blocked_waitq);
> }
> @@ -989,6 +998,10 @@ void fuse_send_init(struct fuse_conn *fc)
> struct fuse_init_args *ia;
>
> ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
> + if (!ia) {
> + process_init_reply(fc, NULL, -ENOTCONN);
> + return;
> + }
>
> ia->in.major = FUSE_KERNEL_VERSION;
> ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
>
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