6.5-stable review patch. If anyone has any objections, please let me know.
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From: Andrew Kanner andrew.kanner@gmail.com
[ Upstream commit a12bbb3cccf03b12847de0f7a6772127f90936ac ]
Syzkaller reported the following issue:
------------[ cut here ]------------ WARNING: CPU: 0 PID: 2807 at mm/vmalloc.c:3247 __vmalloc_node_range (mm/vmalloc.c:3361) Modules linked in: CPU: 0 PID: 2807 Comm: repro Not tainted 6.6.0-rc2+ #12 Hardware name: Generic DT based system unwind_backtrace from show_stack (arch/arm/kernel/traps.c:258) show_stack from dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1)) dump_stack_lvl from __warn (kernel/panic.c:633 kernel/panic.c:680) __warn from warn_slowpath_fmt (./include/linux/context_tracking.h:153 kernel/panic.c:700) warn_slowpath_fmt from __vmalloc_node_range (mm/vmalloc.c:3361 (discriminator 3)) __vmalloc_node_range from vmalloc_user (mm/vmalloc.c:3478) vmalloc_user from xskq_create (net/xdp/xsk_queue.c:40) xskq_create from xsk_setsockopt (net/xdp/xsk.c:953 net/xdp/xsk.c:1286) xsk_setsockopt from __sys_setsockopt (net/socket.c:2308) __sys_setsockopt from ret_fast_syscall (arch/arm/kernel/entry-common.S:68)
xskq_get_ring_size() uses struct_size() macro to safely calculate the size of struct xsk_queue and q->nentries of desc members. But the syzkaller repro was able to set q->nentries with the value initially taken from copy_from_sockptr() high enough to return SIZE_MAX by struct_size(). The next PAGE_ALIGN(size) is such case will overflow the size_t value and set it to 0. This will trigger WARN_ON_ONCE in vmalloc_user() -> __vmalloc_node_range().
The issue is reproducible on 32-bit arm kernel.
Fixes: 9f78bf330a66 ("xsk: support use vaddr as ring") Reported-by: syzbot+fae676d3cf469331fc89@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000c84b4705fb31741e@google.com/T/ Reported-by: syzbot+b132693e925cbbd89e26@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000e20df20606ebab4f@google.com/T/ Signed-off-by: Andrew Kanner andrew.kanner@gmail.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Tested-by: syzbot+fae676d3cf469331fc89@syzkaller.appspotmail.com Acked-by: Magnus Karlsson magnus.karlsson@intel.com Link: https://syzkaller.appspot.com/bug?extid=fae676d3cf469331fc89 Link: https://lore.kernel.org/bpf/20231007075148.1759-1-andrew.kanner@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/xdp/xsk_queue.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/net/xdp/xsk_queue.c b/net/xdp/xsk_queue.c index f8905400ee07a..d2c2640300171 100644 --- a/net/xdp/xsk_queue.c +++ b/net/xdp/xsk_queue.c @@ -34,6 +34,16 @@ struct xsk_queue *xskq_create(u32 nentries, bool umem_queue) q->ring_mask = nentries - 1;
size = xskq_get_ring_size(q, umem_queue); + + /* size which is overflowing or close to SIZE_MAX will become 0 in + * PAGE_ALIGN(), checking SIZE_MAX is enough due to the previous + * is_power_of_2(), the rest will be handled by vmalloc_user() + */ + if (unlikely(size == SIZE_MAX)) { + kfree(q); + return NULL; + } + size = PAGE_ALIGN(size);
q->ring = vmalloc_user(size);