This is a note to let you know that I've just added the patch titled IB/hfi1: Fix sdma.h tx->num_descs off-by-one errors to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ib-hfi1-fix-sdma.h-tx-num_descs-off-by-one-errors.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit db1592bfacca0f1462b0e0462306a79ff1848d83 Author: Patrick Kelsey <pat.kelsey@xxxxxxxxxxxxxxxxxxxx> Date: Thu Feb 16 11:56:28 2023 -0500 IB/hfi1: Fix sdma.h tx->num_descs off-by-one errors [ Upstream commit fd8958efe8779d3db19c9124fce593ce681ac709 ] Fix three sources of error involving struct sdma_txreq.num_descs. When _extend_sdma_tx_descs() extends the descriptor array, it uses the value of tx->num_descs to determine how many existing entries from the tx's original, internal descriptor array to copy to the newly allocated one. As this value was incremented before the call, the copy loop will access one entry past the internal descriptor array, copying its contents into the corresponding slot in the new array. If the call to _extend_sdma_tx_descs() fails, _pad_smda_tx_descs() then invokes __sdma_tx_clean() which uses the value of tx->num_desc to drive a loop that unmaps all descriptor entries in use. As this value was incremented before the call, the unmap loop will invoke sdma_unmap_desc() on a descriptor entry whose contents consist of whatever random data was copied into it during (1), leading to cascading further calls into the kernel and driver using arbitrary data. _sdma_close_tx() was using tx->num_descs instead of tx->num_descs - 1. Fix all of the above by: - Only increment .num_descs after .descp is extended. - Use .num_descs - 1 instead of .num_descs for last .descp entry. Fixes: f4d26d81ad7f ("staging/rdma/hfi1: Add coalescing support for SDMA TX descriptors") Link: https://lore.kernel.org/r/167656658879.2223096.10026561343022570690.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Brendan Cunningham <bcunningham@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Patrick Kelsey <pat.kelsey@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c index a95b654f52540..8ed20392e9f0d 100644 --- a/drivers/infiniband/hw/hfi1/sdma.c +++ b/drivers/infiniband/hw/hfi1/sdma.c @@ -3160,8 +3160,7 @@ int _pad_sdma_tx_descs(struct hfi1_devdata *dd, struct sdma_txreq *tx) { int rval = 0; - tx->num_desc++; - if ((unlikely(tx->num_desc == tx->desc_limit))) { + if ((unlikely(tx->num_desc + 1 == tx->desc_limit))) { rval = _extend_sdma_tx_descs(dd, tx); if (rval) { __sdma_txclean(dd, tx); @@ -3174,6 +3173,7 @@ int _pad_sdma_tx_descs(struct hfi1_devdata *dd, struct sdma_txreq *tx) SDMA_MAP_NONE, dd->sdma_pad_phys, sizeof(u32) - (tx->packet_len & (sizeof(u32) - 1))); + tx->num_desc++; _sdma_close_tx(dd, tx); return rval; } diff --git a/drivers/infiniband/hw/hfi1/sdma.h b/drivers/infiniband/hw/hfi1/sdma.h index d8170fcbfbdd5..b023fc461bd51 100644 --- a/drivers/infiniband/hw/hfi1/sdma.h +++ b/drivers/infiniband/hw/hfi1/sdma.h @@ -631,14 +631,13 @@ static inline void sdma_txclean(struct hfi1_devdata *dd, struct sdma_txreq *tx) static inline void _sdma_close_tx(struct hfi1_devdata *dd, struct sdma_txreq *tx) { - tx->descp[tx->num_desc].qw[0] |= - SDMA_DESC0_LAST_DESC_FLAG; - tx->descp[tx->num_desc].qw[1] |= - dd->default_desc1; + u16 last_desc = tx->num_desc - 1; + + tx->descp[last_desc].qw[0] |= SDMA_DESC0_LAST_DESC_FLAG; + tx->descp[last_desc].qw[1] |= dd->default_desc1; if (tx->flags & SDMA_TXREQ_F_URGENT) - tx->descp[tx->num_desc].qw[1] |= - (SDMA_DESC1_HEAD_TO_HOST_FLAG | - SDMA_DESC1_INT_REQ_FLAG); + tx->descp[last_desc].qw[1] |= (SDMA_DESC1_HEAD_TO_HOST_FLAG | + SDMA_DESC1_INT_REQ_FLAG); } static inline int _sdma_txadd_daddr( @@ -655,6 +654,7 @@ static inline int _sdma_txadd_daddr( type, addr, len); WARN_ON(len > tx->tlen); + tx->num_desc++; tx->tlen -= len; /* special cases for last */ if (!tx->tlen) { @@ -666,7 +666,6 @@ static inline int _sdma_txadd_daddr( _sdma_close_tx(dd, tx); } } - tx->num_desc++; return rval; }