The "struct mana_cfg_rx_steer_req_v2" uses a dynamically sized set of trailing elements. Specifically, it uses a "mana_handle_t" array. So, use the preferred way in the kernel declaring a flexible array [1].
At the same time, prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). Also, avoid the open-coded arithmetic in the memory allocator functions [2] using the "struct_size" macro. Moreover, use the "offsetof" helper to get the indirect table offset instead of the "sizeof" operator and avoid the open-coded arithmetic in pointers using the new flex member. This new structure member also allow us to remove the "req_indir_tab" variable since it is no longer needed. Now, it is also possible to use the "flex_array_size" helper to compute the size of these trailing elements in the "memcpy" function. Specifically, the first commit adds the flex member and the patches 2 and 3 refactor the consumers of the "struct mana_cfg_rx_steer_req_v2". This code was detected with the help of Coccinelle, and audited and modified manually. The Coccinelle script used to detect this code pattern is the following: virtual report @rule1@ type t1; type t2; identifier i0; identifier i1; identifier i2; identifier ALLOC =~ "kmalloc|kzalloc|kmalloc_node|kzalloc_node|vmalloc|vzalloc|kvmalloc|kvzalloc"; position p1; @@ i0 = sizeof(t1) + sizeof(t2) * i1; ... i2 = ALLOC@p1(..., i0, ...); @script:python depends on report@ p1 << rule1.p1; @@ msg = "WARNING: verify allocation on line %s" % (p1[0].line) coccilib.report.print_report(p1[0],msg) Link: https://www.kernel.org/doc/html/next/process/deprecated.html#zero-length-and-one-element-arrays [1] Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2] Signed-off-by: Erick Archer <erick.arc...@outlook.com> --- Changes in v3: - Split the changes in various commits to simplify the acceptance process (Leon Romanovsky). Changes in v2: - Remove the "req_indir_tab" variable (Gustavo A. R. Silva). - Update the commit message. - Add the "__counted_by" attribute. Previous versions: v1 -> https://lore.kernel.org/linux-hardening/as8pr02mb7237974ef1b9bafa618166c38b...@as8pr02mb7237.eurprd02.prod.outlook.com/ v2 -> https://lore.kernel.org/linux-hardening/as8pr02mb723729c5a63f24c312fc9cd18b...@as8pr02mb7237.eurprd02.prod.outlook.com/ --- Erick Archer (3): net: mana: Add flex array to struct mana_cfg_rx_steer_req_v2 RDMA/mana_ib: Prefer struct_size over open coded arithmetic net: mana: Avoid open coded arithmetic drivers/infiniband/hw/mana/qp.c | 12 +++++------- drivers/net/ethernet/microsoft/mana/mana_en.c | 14 ++++++-------- include/net/mana/mana.h | 1 + 3 files changed, 12 insertions(+), 15 deletions(-) -- 2.25.1
