From e5a3449ce16a24bc53c9f41cf36418abe6c27a72 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 25 Mar 2021 14:12:34 -0400 Subject: [PATCH] hostfs: fix memory handling in follow_link() [ Upstream commit 7f6c411c9b50cfab41cc798e003eff27608c7016 ] 1) argument should not be freed in any case - the caller already has it as ->s_fs_info (and uses it a lot afterwards) 2) allocate readlink buffer with kmalloc() - the caller has no way to tell if it's got that (on absolute symlink) or a result of kasprintf(). Sure, for SLAB and SLUB kfree() works on results of kmem_cache_alloc(), but that's not documented anywhere, might change in the future *and* is already not true for SLOB. Fixes: 52b209f7b848 ("get rid of hostfs_read_inode()") Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- fs/hostfs/hostfs_kern.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c index c070c0d8e3e9..d4e360234579 100644 --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -142,7 +142,7 @@ static char *follow_link(char *link) char *name, *resolved, *end; int n; - name = __getname(); + name = kmalloc(PATH_MAX, GFP_KERNEL); if (!name) { n = -ENOMEM; goto out_free; @@ -171,12 +171,11 @@ static char *follow_link(char *link) goto out_free; } - __putname(name); - kfree(link); + kfree(name); return resolved; out_free: - __putname(name); + kfree(name); return ERR_PTR(n); }