Commit 1f206002 authored Oct 22, 2022 by Li Zetao Committed by Greg Kroah-Hartman Mar 11, 2023

ubifs: Fix memory leak in alloc_wbufs()



[ Upstream commit 4a1ff3c5d04b9079b4f768d9a71b51c4af578dd2 ]

kmemleak reported a sequence of memory leaks, and show them as following:

  unreferenced object 0xffff8881575f8400 (size 1024):
    comm "mount", pid 19625, jiffies 4297119604 (age 20.383s)
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<ffffffff8176cecd>] __kmalloc+0x4d/0x150
      [<ffffffffa0406b2b>] ubifs_mount+0x307b/0x7170 [ubifs]
      [<ffffffff819fa8fd>] legacy_get_tree+0xed/0x1d0
      [<ffffffff81936f2d>] vfs_get_tree+0x7d/0x230
      [<ffffffff819b2bd4>] path_mount+0xdd4/0x17b0
      [<ffffffff819b37aa>] __x64_sys_mount+0x1fa/0x270
      [<ffffffff83c14295>] do_syscall_64+0x35/0x80
      [<ffffffff83e0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

  unreferenced object 0xffff8881798a6e00 (size 512):
    comm "mount", pid 19677, jiffies 4297121912 (age 37.816s)
    hex dump (first 32 bytes):
      6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
      6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    backtrace:
      [<ffffffff8176cecd>] __kmalloc+0x4d/0x150
      [<ffffffffa0418342>] ubifs_wbuf_init+0x52/0x480 [ubifs]
      [<ffffffffa0406ca5>] ubifs_mount+0x31f5/0x7170 [ubifs]
      [<ffffffff819fa8fd>] legacy_get_tree+0xed/0x1d0
      [<ffffffff81936f2d>] vfs_get_tree+0x7d/0x230
      [<ffffffff819b2bd4>] path_mount+0xdd4/0x17b0
      [<ffffffff819b37aa>] __x64_sys_mount+0x1fa/0x270
      [<ffffffff83c14295>] do_syscall_64+0x35/0x80
      [<ffffffff83e0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

The problem is that the ubifs_wbuf_init() returns an error in the
loop which in the alloc_wbufs(), then the wbuf->buf and wbuf->inodes
that were successfully alloced before are not freed.

Fix it by adding error hanging path in alloc_wbufs() which frees
the memory alloced before when ubifs_wbuf_init() returns an error.

Fixes: 1e51764a ("UBIFS: add new flash file system")
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 07b60f74

fs/ubifs/super.c

+13 −4

Original line number	Diff line number	Diff line
		@@ -815,7 +815,7 @@ static int alloc_wbufs(struct ubifs_info *c)
		INIT_LIST_HEAD(&c->jheads[i].buds_list);
		err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
		if (err)
		return err;
		goto out_wbuf;

		c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
		c->jheads[i].wbuf.jhead = i;
		@@ -823,7 +823,7 @@ static int alloc_wbufs(struct ubifs_info *c)
		c->jheads[i].log_hash = ubifs_hash_get_desc(c);
		if (IS_ERR(c->jheads[i].log_hash)) {
		err = PTR_ERR(c->jheads[i].log_hash);
		goto out;
		goto out_log_hash;
		}
		}

		@@ -836,9 +836,18 @@ static int alloc_wbufs(struct ubifs_info *c)

		return 0;

		out:
		while (i--)
		out_log_hash:
		kfree(c->jheads[i].wbuf.buf);
		kfree(c->jheads[i].wbuf.inodes);

		out_wbuf:
		while (i--) {
		kfree(c->jheads[i].wbuf.buf);
		kfree(c->jheads[i].wbuf.inodes);
		kfree(c->jheads[i].log_hash);
		}
		kfree(c->jheads);
		c->jheads = NULL;

		return err;
		}