io_rsrc_data_alloc() allocates an array of io_rsrc_node pointers and assigns it to io_rsrc_data's nodes field along with the size in the nr field. However, it doesn't initialize the io_rsrc_node pointers in the array. If an error in io_sqe_buffers_register(), io_alloc_file_tables(), io_sqe_files_register(), or io_clone_buffers() causes them to exit before all the io_rsrc_node pointers in the array have been assigned, io_rsrc_data_free() will read the uninitialized elements, triggering undefined behavior. Additionally, if dst_off exceeds the current size of the destination buffer table in io_clone_buffers(), the io_rsrc_node pointers in between won't be initialized. Any access to those registered buffer indices will result in undefined behavior. Allocate the array with kvcalloc() instead of kvmalloc_array() to ensure the io_rsrc_node pointers are initialized to NULL (indicating no registered buffer/file node). Signed-off-by: Caleb Sander Mateos Fixes: 7029acd8a950 ("io_uring/rsrc: get rid of per-ring io_rsrc_node list") --- io_uring/rsrc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index f75f5e43fa4a..3f3f355f6613 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -209,12 +209,12 @@ __cold void io_rsrc_data_free(struct io_ring_ctx *ctx, data->nr = 0; } __cold int io_rsrc_data_alloc(struct io_rsrc_data *data, unsigned nr) { - data->nodes = kvmalloc_array(nr, sizeof(struct io_rsrc_node *), - GFP_KERNEL_ACCOUNT | __GFP_ZERO); + data->nodes = kvcalloc(nr, sizeof(struct io_rsrc_node *), + GFP_KERNEL_ACCOUNT | __GFP_ZERO); if (data->nodes) { data->nr = nr; return 0; } return -ENOMEM; -- 2.45.2