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author | Andrew Kanner <andrew.kanner@gmail.com> | 2023-10-07 10:51:49 +0300 |
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committer | Daniel Borkmann <daniel@iogearbox.net> | 2023-10-09 16:13:29 +0200 |
commit | a12bbb3cccf03b12847de0f7a6772127f90936ac (patch) | |
tree | d69b3f67b999f0d37fef4392c1edfd170c43786c | |
parent | 7112cd26e606c7ba51f9cc5c1905f06039f6f379 (diff) | |
download | linux-stable-a12bbb3cccf03b12847de0f7a6772127f90936ac.tar.gz linux-stable-a12bbb3cccf03b12847de0f7a6772127f90936ac.tar.bz2 linux-stable-a12bbb3cccf03b12847de0f7a6772127f90936ac.zip |
xdp: Fix zero-size allocation warning in xskq_create()
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
-rw-r--r-- | net/xdp/xsk_queue.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/net/xdp/xsk_queue.c b/net/xdp/xsk_queue.c index f8905400ee07..d2c264030017 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); |