Subject: CVE-2024-50001: net/mlx5: Fix error path in multi-packet WQE transmit

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix error path in multi-packet WQE transmit

Remove the erroneous unmap in case no DMA mapping was established

The multi-packet WQE transmit code attempts to obtain a DMA mapping for
the skb. This could fail, e.g. under memory pressure, when the IOMMU
driver just can't allocate more memory for page tables. While the code
tries to handle this in the path below the err_unmap label it erroneously
unmaps one entry from the sq's FIFO list of active mappings. Since the
current map attempt failed this unmap is removing some random DMA mapping
that might still be required. If the PCI function now presents that IOVA,
the IOMMU may assumes a rogue DMA access and e.g. on s390 puts the PCI
function in error state.

The erroneous behavior was seen in a stress-test environment that created
memory pressure.

The Linux kernel CVE team has assigned CVE-2024-50001 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.10 with commit 5af75c747e2a and fixed in 5.10.227 with commit ca36d6c1a49b
	Issue introduced in 5.10 with commit 5af75c747e2a and fixed in 5.15.168 with commit ce828b347cf1
	Issue introduced in 5.10 with commit 5af75c747e2a and fixed in 6.1.113 with commit fc357e781769
	Issue introduced in 5.10 with commit 5af75c747e2a and fixed in 6.6.55 with commit 26fad69b34fc
	Issue introduced in 5.10 with commit 5af75c747e2a and fixed in 6.10.14 with commit ecf310aaf256
	Issue introduced in 5.10 with commit 5af75c747e2a and fixed in 6.11.3 with commit 8bb8c12fb5e2
	Issue introduced in 5.10 with commit 5af75c747e2a and fixed in 6.12-rc2 with commit 2bcae12c795f

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-50001
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/mellanox/mlx5/core/en_tx.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/ca36d6c1a49b6965c86dd528a73f38bc62d9c625
	https://git.kernel.org/stable/c/ce828b347cf1b3c1b12b091d02463c35ce5097f5
	https://git.kernel.org/stable/c/fc357e78176945ca7bcacf92ab794b9ccd41b4f4
	https://git.kernel.org/stable/c/26fad69b34fcba80d5c7d9e651f628e6ac927754
	https://git.kernel.org/stable/c/ecf310aaf256acbc8182189fe0aa1021c3ddef72
	https://git.kernel.org/stable/c/8bb8c12fb5e2b1f03d603d493c92941676f109b5
	https://git.kernel.org/stable/c/2bcae12c795f32ddfbf8c80d1b5f1d3286341c32