diff options
| author | Savino Dicanosa <sd7.dev@pm.me> | 2023-03-21 19:44:02 +0000 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-03-22 11:04:55 -0600 |
| commit | 02a4d923e4400a36d340ea12d8058f69ebf3a383 (patch) | |
| tree | aaa0562aae658d643a59e6e5c31078ef6a9fc870 | |
| parent | 74e2e17ee1f8d8a0928b90434ad7e2df70f8483e (diff) | |
io_uring/rsrc: fix null-ptr-deref in io_file_bitmap_get()
When fixed files are unregistered, file_alloc_end and alloc_hint
are not cleared. This can later cause a NULL pointer dereference in
io_file_bitmap_get() if auto index selection is enabled via
IORING_FILE_INDEX_ALLOC:
[ 6.519129] BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
[ 6.541468] RIP: 0010:_find_next_zero_bit+0x1a/0x70
[...]
[ 6.560906] Call Trace:
[ 6.561322] <TASK>
[ 6.561672] io_file_bitmap_get+0x38/0x60
[ 6.562281] io_fixed_fd_install+0x63/0xb0
[ 6.562851] ? __pfx_io_socket+0x10/0x10
[ 6.563396] io_socket+0x93/0xf0
[ 6.563855] ? __pfx_io_socket+0x10/0x10
[ 6.564411] io_issue_sqe+0x5b/0x3d0
[ 6.564914] io_submit_sqes+0x1de/0x650
[ 6.565452] __do_sys_io_uring_enter+0x4fc/0xb20
[ 6.566083] ? __do_sys_io_uring_register+0x11e/0xd80
[ 6.566779] do_syscall_64+0x3c/0x90
[ 6.567247] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[...]
To fix the issue, set file alloc range and alloc_hint to zero after
file tables are freed.
Cc: stable@vger.kernel.org
Fixes: 4278a0deb1f6 ("io_uring: defer alloc_hint update to io_file_bitmap_set()")
Signed-off-by: Savino Dicanosa <sd7.dev@pm.me>
[axboe: add explicit bitmap == NULL check as well]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | io_uring/filetable.c | 3 | ||||
| -rw-r--r-- | io_uring/rsrc.c | 1 |
2 files changed, 4 insertions, 0 deletions
diff --git a/io_uring/filetable.c b/io_uring/filetable.c index 68dfc6936aa7..b80614e7d605 100644 --- a/io_uring/filetable.c +++ b/io_uring/filetable.c @@ -19,6 +19,9 @@ static int io_file_bitmap_get(struct io_ring_ctx *ctx) unsigned long nr = ctx->file_alloc_end; int ret; + if (!table->bitmap) + return -ENFILE; + do { ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint); if (ret != nr) diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index e2bac9f89902..7a43aed8e395 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -794,6 +794,7 @@ void __io_sqe_files_unregister(struct io_ring_ctx *ctx) } #endif io_free_file_tables(&ctx->file_table); + io_file_table_set_alloc_range(ctx, 0, 0); io_rsrc_data_free(ctx->file_data); ctx->file_data = NULL; ctx->nr_user_files = 0; |