io_uring: Replace 0-length array with flexible array
Subsystems (2)
PATCH v2 1/1 io_uring: Replace 0-length array with flexible array
Zero-length arrays are deprecated[1]. Replace struct io_uring_buf_ring's "bufs" with a flexible array member. (How is the size of this array verified?) Detected with GCC 13, using -fstrict-flex-arrays=3:
In function 'io_ring_buffer_select',
inlined from 'io_buffer_select' at io_uring/kbuf.c:183:10:
io_uring/kbuf.c:141:23: warning: array subscript 255 is outside the bounds of an interior zero-length array 'struct io_uring_buf[0]' [-Wzero-length-bounds]
141 | buf = &br->bufs[head];
| ^~~~~~~~~~~~~~~
In file included from include/linux/io_uring.h:7,
from io_uring/kbuf.c:10:
include/uapi/linux/io_uring.h: In function 'io_buffer_select':
include/uapi/linux/io_uring.h:628:41: note: while referencing 'bufs'
628 | struct io_uring_buf bufs[0];
| ^~~~[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
---
v2: use helper since these flex arrays are in a union.
v1: https://lore.kernel.org/lkml/[email protected]
--- include/uapi/linux/io_uring.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
include/uapi/linux/io_uring.h +1 -1
@@ -625,7 +625,7 @@ struct io_uring_buf_ring {__u16 resv3;__u16 tail; }; -struct io_uring_buf bufs[0 ]; + __DECLARE_FLEX_ARRAY(struct io_uring_buf, bufs); }; };
Signature · 1 line
2.34.1
Quoted 18 lines · Kees Cook
Zero-length arrays are deprecated[1]. Replace struct io_uring_buf_ring's "bufs" with a flexible array member. (How is the size of this array verified?) Detected with GCC 13, using -fstrict-flex-arrays=3:
In function '
io_ring_buffer_select',inlined from 'io_buffer_select' at io_uring/kbuf.c:183:10: io_uring/kbuf.c:141:23: warning: array subscript 255 is outside the bounds of an interior zero-length array 'struct io_uring_buf[0]' [-Wzero-length-bounds] 141 | buf = &br->bufs[head]; | ^~~~~~~~~~~~~~~ In file included from include/linux/io_uring.h:7, from io_uring/kbuf.c:10: include/uapi/linux/io_uring.h: In function 'io_buffer_select': include/uapi/linux/io_uring.h:628:41: note: while referencing 'bufs' 628 | struct io_uring_buf bufs[0]; | ^~~~[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
Quoted 7 lines
Fixes c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers")Cc Jens Axboe <[email protected]>Cc Pavel Begunkov <[email protected]>Cc "Gustavo A. R. Silva" <[email protected]>Signed-off-by Kees Cook <[email protected]>
Thanks!
--
Gustavo
Quoted 23 lines
---
v2: use helper since these flex arrays are in a union.
v1: https://lore.kernel.org/lkml/[email protected]--- include/uapi/linux/io_uring.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)include/uapi/linux/io_uring.h +1
-1@@ -625,7 +625,7 @@ struct io_uring_buf_ring {__u16 resv3;__u16 tail; }; -struct io_uring_buf bufs[0 ]; + __DECLARE_FLEX_ARRAY(struct io_uring_buf, bufs); }; };Signature · 1 line
2.34.1