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io_uring/query: buffer size calculations with a union

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Instead of having an array of a calculated size as a buffer, put all
query uapi structures into a union and pass that around. That way
everything is well typed, and the compiler will prevent opcode handling
using a structure not accounted into the buffer size.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov
2025-11-06 12:31:56 +00:00
committed by Jens Axboe
parent b6c5f9454e
commit 21bd7b14a3
1 changed files with 11 additions and 9 deletions
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20
io_uring/query.c
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@@ -5,14 +5,16 @@
#include "query.h"
#include "io_uring.h"
#define IO_MAX_QUERY_SIZE (sizeof(struct io_uring_query_opcode))
union io_query_data {
struct io_uring_query_opcode opcodes;
};
#define IO_MAX_QUERY_SIZE sizeof(union io_query_data)
#define IO_MAX_QUERY_ENTRIES 1000
static ssize_t io_query_ops(void *data)
static ssize_t io_query_ops(union io_query_data *data)
{
struct io_uring_query_opcode *e = data;
BUILD_BUG_ON(sizeof(*e) > IO_MAX_QUERY_SIZE);
struct io_uring_query_opcode *e = &data->opcodes;
e->nr_request_opcodes = IORING_OP_LAST;
e->nr_register_opcodes = IORING_REGISTER_LAST;
@@ -24,7 +26,7 @@ static ssize_t io_query_ops(void *data)
}
static int io_handle_query_entry(struct io_ring_ctx *ctx,
void *data, void __user *uhdr,
union io_query_data *data, void __user *uhdr,
u64 *next_entry)
{
struct io_uring_query_hdr hdr;
@@ -73,11 +75,11 @@ out:
int io_query(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args)
{
char entry_buffer[IO_MAX_QUERY_SIZE];
union io_query_data entry_buffer;
void __user *uhdr = arg;
int ret, nr = 0;
memset(entry_buffer, 0, sizeof(entry_buffer));
memset(&entry_buffer, 0, sizeof(entry_buffer));
if (nr_args)
return -EINVAL;
@@ -85,7 +87,7 @@ int io_query(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args)
while (uhdr) {
u64 next_hdr;
ret = io_handle_query_entry(ctx, entry_buffer, uhdr, &next_hdr);
ret = io_handle_query_entry(ctx, &entry_buffer, uhdr, &next_hdr);
if (ret)
return ret;
uhdr = u64_to_user_ptr(next_hdr);