Commit 6457c20e authored by Murphy Zhou's avatar Murphy Zhou Committed by Steve French

fs/cifs/smb2pdu.c: fix buffer free in SMB2_ioctl_free

The 2nd buffer could be NULL even if iov_len is not zero. This can
trigger a panic when handling symlinks. It's easy to reproduce with
LTP fs_racer scripts[1] which are randomly craete/delete/link files
and dirs. Fix this panic by checking if the 2nd buffer is padding
before kfree, like what we do in SMB2_open_free.

[1] https://github.com/linux-test-project/ltp/tree/master/testcases/kernel/fs/racer

Fixes: 2c87d6a9 ("cifs: Allocate memory for all iovs in smb2_ioctl")
Signed-off-by: default avatarMurphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
Reviewed-by: default avatarRonnie sahlberg <lsahlber@redhat.com>
parent 21078203
...@@ -2620,10 +2620,12 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, ...@@ -2620,10 +2620,12 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
void void
SMB2_ioctl_free(struct smb_rqst *rqst) SMB2_ioctl_free(struct smb_rqst *rqst)
{ {
int i;
if (rqst && rqst->rq_iov) { if (rqst && rqst->rq_iov) {
cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */ cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
if (rqst->rq_iov[1].iov_len) for (i = 1; i < rqst->rq_nvec; i++)
kfree(rqst->rq_iov[1].iov_base); if (rqst->rq_iov[i].iov_base != smb2_padding)
kfree(rqst->rq_iov[i].iov_base);
} }
} }
......
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