From: Christian Borntraeger Date: Mon, 6 Jul 2026 14:15:37 +0000 (+0200) Subject: vdpa/mlx5: Fix buffer length in create_direct_keys() X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=727e1f569855df83579edbd73dcb4a0723543a12;p=thirdparty%2Fkernel%2Flinux.git vdpa/mlx5: Fix buffer length in create_direct_keys() We have seen in our CI the following KASAN message: BUG: KASAN: slab-out-of-bounds in cmd_exec+0x550/0xca0 [mlx5_core] Read of size 272 at addr 0000000176795020 by task qemu-system-s39/82764 [...] [<000011388ab3a7a0>] cmd_exec+0x550/0xca0 [mlx5_core] [<000011388ab3b61c>] mlx5_cmd_exec_cb+0x25c/0x4f0 [mlx5_core] [<000011388b21e82e>] mlx5_vdpa_exec_async_cmds+0x22e/0x5e0 [mlx5_vdpa] [<000011388b21fd44>] create_direct_keys+0x954/0xef0 [mlx5_vdpa] [...] The buggy address is located 4128 bytes inside of allocated 4384-byte region [0000000176794000, 0000000176795120) So in essence we read 16 bytes beyond 4384-byte allocation. create_direct_keys calculates the pointer and length for in and out buffers. The size calculation for in includes the entire structure size (out + in + mtt[]) but the pointer passed to cmd_exec points only to the 'in' field, skipping the 'out' field. This causes mlx5_copy_to_msg() to read beyond the allocated buffer by sizeof(out) bytes when copying command data. Properly calculate the input size to match the pointer and allocation size. Fixes: 0071b138d44a ("vdpa/mlx5: Create direct MKEYs in parallel") Signed-off-by: Christian Borntraeger Tested-by: Dragos Tatulea Reviewed-by: Dragos Tatulea Signed-off-by: Michael S. Tsirkin Message-ID: <20260706141537.3510294-1-borntraeger@linux.ibm.com> --- diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c index 7d681961a5cc..77a479aeaa85 100644 --- a/drivers/vdpa/mlx5/core/mr.c +++ b/drivers/vdpa/mlx5/core/mr.c @@ -233,7 +233,8 @@ static int create_direct_keys(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr * cmds[i].out = cmd_mem->out; cmds[i].outlen = sizeof(cmd_mem->out); cmds[i].in = cmd_mem->in; - cmds[i].inlen = struct_size(cmd_mem, mtt, mttcount); + cmds[i].inlen = struct_size(cmd_mem, mtt, mttcount) - + offsetof(struct mlx5_create_mkey_mem, in); fill_create_direct_mr(mvdev, dmr, cmd_mem);