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cifs: allow calling SMB2_xxx_free(NULL)

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commit 32a1fb36f6e50183871c2c1fcf5493c633e84732 upstream.

Change these free functions to allow passing NULL as the argument and
treat it as a no-op just like free(NULL) would.
Or, if rqst->rq_iov is NULL.

The second scenario could happen for smb2_queryfs() if the call
to SMB2_query_info_init() fails and we go to qfs_exit to clean up
and free all resources.
In that case we have not yet assigned rqst[2].rq_iov and thus
the rq_iov dereference in SMB2_close_free() will cause a NULL pointer
dereference.

[ bp: upstream patch also fixes SMB2_set_info_free which was introduced in 4.20 ]

Fixes:  1eb9fb52040f ("cifs: create SMB2_open_init()/SMB2_open_free() helpers")

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ronnie Sahlberg 2018-10-24 11:50:33 +10:00 committed by Greg Kroah-Hartman
parent e5d7b94cc4
commit b4d965a37d
1 changed files with 10 additions and 6 deletions
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16
fs/cifs/smb2pdu.c
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@ -2243,10 +2243,12 @@ SMB2_open_free(struct smb_rqst *rqst)
{
int i;
cifs_small_buf_release(rqst->rq_iov[0].iov_base);
for (i = 1; i < rqst->rq_nvec; i++)
if (rqst->rq_iov[i].iov_base != smb2_padding)
kfree(rqst->rq_iov[i].iov_base);
if (rqst && rqst->rq_iov) {
cifs_small_buf_release(rqst->rq_iov[0].iov_base);
for (i = 1; i < rqst->rq_nvec; i++)
if (rqst->rq_iov[i].iov_base != smb2_padding)
kfree(rqst->rq_iov[i].iov_base);
}
}
int
@ -2535,7 +2537,8 @@ SMB2_close_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
void
SMB2_close_free(struct smb_rqst *rqst)
{
cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
if (rqst && rqst->rq_iov)
cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
}
int
@ -2685,7 +2688,8 @@ SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
void
SMB2_query_info_free(struct smb_rqst *rqst)
{
cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
if (rqst && rqst->rq_iov)
cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
}
static int