v9fs_dir_readdir: fix double-free on p9stat_read error (81c99089) · Commits · 戴 / test

p9stat_read will call p9stat_free on error, we should only free the struct content on success. There also is no need to "p9stat_init" st as the read function will zero the whole struct for us anyway, so clean up the code a bit while we are here. Link: http://lkml.kernel.org/r/1535410108-20650-1-git-send-email-asmadeus@codewreck.org Signed-off-by:

Dominique Martinet <dominique.martinet@cea.fr> Reported-by:

<syzbot+d4252148d198410b864f@syzkaller.appspotmail.com>

fs/9p/vfs_dir.c

+0 −11

Original line number	Diff line number	Diff line
		@@ -76,15 +76,6 @@ static inline int dt_type(struct p9_wstat *mistat)
		return rettype;
		}

		static void p9stat_init(struct p9_wstat *stbuf)
		{
		stbuf->name = NULL;
		stbuf->uid = NULL;
		stbuf->gid = NULL;
		stbuf->muid = NULL;
		stbuf->extension = NULL;
		}

		/**
		* v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir
		* @filp: opened file structure
		@@ -145,12 +136,10 @@ static int v9fs_dir_readdir(struct file file, struct dir_context ctx)
		rdir->tail = n;
		}
		while (rdir->head < rdir->tail) {
		p9stat_init(&st);
		err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
		rdir->tail - rdir->head, &st);
		if (err) {
		p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
		p9stat_free(&st);
		return -EIO;
		}
		reclen = st.size+2;

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