2018-12-19 15:01:43

by Nicholas Mc Guire

[permalink] [raw]
Subject: [PATCH] cifs: handle allocation failures early

kzalloc can return NULL so a check is needed. Further move the
allocation checks before the remaining initialization and bail
out without initialization if allocation failed returning NULL.

Signed-off-by: Joe Perches <[email protected]>
Signed-off-by: Nicholas Mc Guire <[email protected]>
Fixes: 3d4ef9a15343 ("smb3: fix redundant opens on root")
---

Missing kzalloc check located with an experimental coccinelle script

While at it make checkpatch happy by using *ret_buf->crfid.fid
rather than struct cifs_fid and use a more common style by returning
early on the first possible failure too so the block can be unindented.

Patch was compile tested with: x86_64_defconfig + CIFS=m
(with an unrelated smatch warnings and some pending cocci fixes)

Patch is against v4.20-rc7 (localversion-next is next-20181219)

fs/cifs/misc.c | 33 +++++++++++++++++++--------------
1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 113980d..2d4b5fb 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -111,21 +111,26 @@ struct cifs_tcon *
tconInfoAlloc(void)
{
struct cifs_tcon *ret_buf;
- ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
- if (ret_buf) {
- atomic_inc(&tconInfoAllocCount);
- ret_buf->tidStatus = CifsNew;
- ++ret_buf->tc_count;
- INIT_LIST_HEAD(&ret_buf->openFileList);
- INIT_LIST_HEAD(&ret_buf->tcon_list);
- spin_lock_init(&ret_buf->open_file_lock);
- mutex_init(&ret_buf->crfid.fid_mutex);
- ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid),
- GFP_KERNEL);
- spin_lock_init(&ret_buf->stat_lock);
- atomic_set(&ret_buf->num_local_opens, 0);
- atomic_set(&ret_buf->num_remote_opens, 0);
+ ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
+ if (!ret_buf)
+ return NULL;
+ ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), GFP_KERNEL);
+ if (!ret_buf->crfid.fid) {
+ kfree(ret_buf);
+ return NULL;
}
+
+ atomic_inc(&tconInfoAllocCount);
+ ret_buf->tidStatus = CifsNew;
+ ++ret_buf->tc_count;
+ INIT_LIST_HEAD(&ret_buf->openFileList);
+ INIT_LIST_HEAD(&ret_buf->tcon_list);
+ spin_lock_init(&ret_buf->open_file_lock);
+ mutex_init(&ret_buf->crfid.fid_mutex);
+ spin_lock_init(&ret_buf->stat_lock);
+ atomic_set(&ret_buf->num_local_opens, 0);
+ atomic_set(&ret_buf->num_remote_opens, 0);
+
return ret_buf;
}

--
2.1.4



2018-12-19 16:02:43

by Aurélien Aptel

[permalink] [raw]
Subject: Re: [PATCH] cifs: handle allocation failures early

Reviewed-by: Aurelien Aptel <[email protected]>

--
Aurélien Aptel / SUSE Labs Samba Team
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GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)