diff options
| author | GUO Zihua <guozihua@huawei.com> | 2022-11-17 17:11:57 +0800 |
|---|---|---|
| committer | Dominique Martinet <asmadeus@codewreck.org> | 2022-11-18 22:29:57 +0900 |
| commit | 578b565b240afdfe0596d183f473f333eb9d3008 (patch) | |
| tree | 70a0cee2ee295fce7fa73ce6dced0fcd075dbab1 | |
| parent | 11c10956515b8ec44cf4f2a7b9d8bf8b9dc05ec4 (diff) | |
9p/fd: Fix write overflow in p9_read_work
This error was reported while fuzzing:
BUG: KASAN: slab-out-of-bounds in _copy_to_iter+0xd35/0x1190
Write of size 4043 at addr ffff888008724eb1 by task kworker/1:1/24
CPU: 1 PID: 24 Comm: kworker/1:1 Not tainted 6.1.0-rc5-00002-g1adf73218daa-dirty #223
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
Workqueue: events p9_read_work
Call Trace:
<TASK>
dump_stack_lvl+0x4c/0x64
print_report+0x178/0x4b0
kasan_report+0xae/0x130
kasan_check_range+0x179/0x1e0
memcpy+0x38/0x60
_copy_to_iter+0xd35/0x1190
copy_page_to_iter+0x1d5/0xb00
pipe_read+0x3a1/0xd90
__kernel_read+0x2a5/0x760
kernel_read+0x47/0x60
p9_read_work+0x463/0x780
process_one_work+0x91d/0x1300
worker_thread+0x8c/0x1210
kthread+0x280/0x330
ret_from_fork+0x22/0x30
</TASK>
Allocated by task 457:
kasan_save_stack+0x1c/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0x7e/0x90
__kmalloc+0x59/0x140
p9_fcall_init.isra.11+0x5d/0x1c0
p9_tag_alloc+0x251/0x550
p9_client_prepare_req+0x162/0x350
p9_client_rpc+0x18d/0xa90
p9_client_create+0x670/0x14e0
v9fs_session_init+0x1fd/0x14f0
v9fs_mount+0xd7/0xaf0
legacy_get_tree+0xf3/0x1f0
vfs_get_tree+0x86/0x2c0
path_mount+0x885/0x1940
do_mount+0xec/0x100
__x64_sys_mount+0x1a0/0x1e0
do_syscall_64+0x3a/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
This BUG pops up when trying to reproduce
https://syzkaller.appspot.com/bug?id=6c7cd46c7bdd0e86f95d26ec3153208ad186f9fa
The callstack is different but the issue is valid and re-producable with
the same re-producer in the link.
The root cause of this issue is that we check the size of the message
received against the msize of the client in p9_read_work. However, it
turns out that capacity is no longer consistent with msize. Thus,
the message size should be checked against sdata capacity.
As the msize is non-consistant with the capacity of the tag and as we
are now checking message size against capacity directly, there is no
point checking message size against msize. So remove it.
Link: https://lkml.kernel.org/r/20221117091159.31533-2-guozihua@huawei.com
Link: https://lkml.kernel.org/r/20221117091159.31533-3-guozihua@huawei.com
Reported-by: syzbot+0f89bd13eaceccc0e126@syzkaller.appspotmail.com
Fixes: 60ece0833b6c ("net/9p: allocate appropriate reduced message buffers")
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
[Dominique: squash patches 1 & 2 and fix size including header part]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
| -rw-r--r-- | net/9p/trans_fd.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index bd28e63d7666..27c5c938ccd1 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -324,14 +324,6 @@ static void p9_read_work(struct work_struct *work) goto error; } - if (m->rc.size >= m->client->msize) { - p9_debug(P9_DEBUG_ERROR, - "requested packet size too big: %d\n", - m->rc.size); - err = -EIO; - goto error; - } - p9_debug(P9_DEBUG_TRANS, "mux %p pkt: size: %d bytes tag: %d\n", m, m->rc.size, m->rc.tag); @@ -344,6 +336,14 @@ static void p9_read_work(struct work_struct *work) goto error; } + if (m->rc.size > m->rreq->rc.capacity) { + p9_debug(P9_DEBUG_ERROR, + "requested packet size too big: %d for tag %d with capacity %zd\n", + m->rc.size, m->rc.tag, m->rreq->rc.capacity); + err = -EIO; + goto error; + } + if (!m->rreq->rc.sdata) { p9_debug(P9_DEBUG_ERROR, "No recv fcall for tag %d (req %p), disconnecting!\n", |