When I implemented virtio's hash-related features to tun/tap [1], I found tun/tap does not fill the entire region reserved for the virtio header, leaving some uninitialized hole in the middle of the buffer after read()/recvmesg().
This series fills the uninitialized hole. More concretely, the num_buffers field will be initialized with 1, and the other fields will be inialized with 0. Setting the num_buffers field to 1 is mandated by virtio 1.0 [2]. The change to virtio header is preceded by another change that refactors tun and tap to unify their virtio-related code. [1]: https://lore.kernel.org/r/[email protected] [2]: https://lore.kernel.org/r/[email protected]/ Signed-off-by: Akihiko Odaki <[email protected]> --- Changes in v6: - Added an intermediate variable in tun_vnet_legacy_is_little_endian() to reduce a complexity of an expression. - Noted that functions are renamed in the message of patch "tun: Extract the vnet handling code". - Used clamp() in patch "tap: Keep hdr_len in tap_get_user()". - Link to v5: https://lore.kernel.org/r/[email protected] Changes in v5: - s/vnet_hdr_len_sz/vnet_hdr_sz/ for patch "tun: Decouple vnet handling" (Willem de Bruijn) - Changed to inline vnet implementations to TUN and TAP. - Dropped patch "tun: Avoid double-tracking iov_iter length changes" and "tap: Avoid double-tracking iov_iter length changes". - Link to v4: https://lore.kernel.org/r/[email protected] Changes in v4: - s/sz/vnet_hdr_len_sz/ for patch "tun: Decouple vnet handling" (Willem de Bruijn) - Reverted to add CONFIG_TUN_VNET. - Link to v3: https://lore.kernel.org/r/[email protected] Changes in v3: - Dropped changes to fill the vnet header. - Splitted patch "tun: Unify vnet implementation". - Reverted spurious changes in patch "tun: Unify vnet implementation". - Merged tun_vnet.c into TAP. - Link to v2: https://lore.kernel.org/r/[email protected] Changes in v2: - Fixed num_buffers endian. - Link to v1: https://lore.kernel.org/r/[email protected] --- Akihiko Odaki (7): tun: Refactor CONFIG_TUN_VNET_CROSS_LE tun: Keep hdr_len in tun_get_user() tun: Decouple vnet from tun_struct tun: Decouple vnet handling tun: Extract the vnet handling code tap: Keep hdr_len in tap_get_user() tap: Use tun's vnet-related code MAINTAINERS | 2 +- drivers/net/tap.c | 166 +++++------------------------------------- drivers/net/tun.c | 193 ++++++------------------------------------------- drivers/net/tun_vnet.h | 185 +++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 229 insertions(+), 317 deletions(-) --- base-commit: a32e14f8aef69b42826cf0998b068a43d486a9e9 change-id: 20241230-tun-66e10a49b0c7 Best regards, -- Akihiko Odaki <[email protected]>
