diff options
| author | David Carlier <devnexen@gmail.com> | 2026-05-19 21:35:30 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-05-20 18:59:01 -0700 |
| commit | 4eb82ba543421e9e38cc14e4e82058b78850df50 (patch) | |
| tree | 9c6521c3972345a6ad244b75eb716e7fdce66740 /net/core | |
| parent | 5027c886e26cdf02b4cb114e47d922855e2e37e0 (diff) | |
net: devmem: reject dma-buf bind with non-page-aligned size or SG length
net_devmem_bind_dmabuf() trusts dmabuf->size and sg_dma_len() to be
PAGE_SIZE multiples without checking:
- tx_vec is sized dmabuf->size / PAGE_SIZE, and
net_devmem_get_niov_at() only bounds-checks virt_addr < dmabuf->size
before indexing tx_vec[virt_addr / PAGE_SIZE]. With size =
N*PAGE_SIZE + r (1 <= r < PAGE_SIZE), sendmsg() at iov_base =
N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past.
- owner->area.num_niovs = len / PAGE_SIZE while gen_pool_add_owner()
covers the full byte len, so a non-page-multiple non-final sg
desyncs num_niovs from the gen_pool region for every later sg, on
both RX and TX.
dma-buf does not require page-aligned sizes, so the bind path has to
enforce what its own indexing assumes. Reject both with -EINVAL.
The size check is TX-only (only tx_vec is sized off dmabuf->size); the
SG-length check covers both directions.
Fixes: bd61848900bf ("net: devmem: Implement TX path")
Cc: stable@vger.kernel.org
Signed-off-by: David Carlier <devnexen@gmail.com>
Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Link: https://patch.msgid.link/20260519203530.66310-1-devnexen@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/devmem.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/net/core/devmem.c b/net/core/devmem.c index 468344739db2..4f71de44c0fb 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -241,6 +241,11 @@ net_devmem_bind_dmabuf(struct net_device *dev, } if (direction == DMA_TO_DEVICE) { + if (!IS_ALIGNED(dmabuf->size, PAGE_SIZE)) { + err = -EINVAL; + NL_SET_ERR_MSG(extack, "TX dma-buf size must be a multiple of PAGE_SIZE"); + goto err_unmap; + } binding->tx_vec = kvmalloc_objs(struct net_iov *, dmabuf->size / PAGE_SIZE); if (!binding->tx_vec) { @@ -267,6 +272,12 @@ net_devmem_bind_dmabuf(struct net_device *dev, size_t len = sg_dma_len(sg); struct net_iov *niov; + if (!IS_ALIGNED(len, PAGE_SIZE)) { + err = -EINVAL; + NL_SET_ERR_MSG(extack, "dma-buf SG length must be PAGE_SIZE aligned"); + goto err_free_chunks; + } + owner = kzalloc_node(sizeof(*owner), GFP_KERNEL, dev_to_node(&dev->dev)); if (!owner) { |