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: 2c87d6a ("cifs: Allocate memory for all iovs in smb2_ioctl") Signed-off-by: Murphy Zhou <jencce.kernel@xxxxxxxxx> --- fs/cifs/smb2pdu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 710ceb8..c36f940 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -2619,10 +2619,12 @@ int smb311_posix_mkdir(const unsigned int xid, struct inode *inode, void SMB2_ioctl_free(struct smb_rqst *rqst) { + int i; if (rqst && rqst->rq_iov) { cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */ - if (rqst->rq_iov[1].iov_len) - kfree(rqst->rq_iov[1].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); } } -- 1.8.3.1
