linux.git/kernel/relay.c, branch v5.10.258

relayfs: fix out-of-bounds access in relay_file_read

2023-05-17T09:47:34+00:00

commit 43ec16f1450f4936025a9bdf1a273affdb9732c1 upstream.

There is a crash in relay_file_read, as the var from
point to the end of last subbuf.

The oops looks something like:
pc : __arch_copy_to_user+0x180/0x310
lr : relay_file_read+0x20c/0x2c8
Call trace:
 __arch_copy_to_user+0x180/0x310
 full_proxy_read+0x68/0x98
 vfs_read+0xb0/0x1d0
 ksys_read+0x6c/0xf0
 __arm64_sys_read+0x20/0x28
 el0_svc_common.constprop.3+0x84/0x108
 do_el0_svc+0x74/0x90
 el0_svc+0x1c/0x28
 el0_sync_handler+0x88/0xb0
 el0_sync+0x148/0x180

We get the condition by analyzing the vmcore:

1). The last produced byte and last consumed byte
    both at the end of the last subbuf

2). A softirq calls function(e.g __blk_add_trace)
    to write relay buffer occurs when an program is calling
    relay_file_read_avail().

        relay_file_read
                relay_file_read_avail
                        relay_file_read_consume(buf, 0, 0);
                        //interrupted by softirq who will write subbuf
                        ....
                        return 1;
                //read_start point to the end of the last subbuf
                read_start = relay_file_read_start_pos
                //avail is equal to subsize
                avail = relay_file_read_subbuf_avail
                //from  points to an invalid memory address
                from = buf->start + read_start
                //system is crashed
                copy_to_user(buffer, from, avail)

Link: https://lkml.kernel.org/r/20230419040203.37676-1-zhang.zhengming@h3c.com
Fixes: 8d62fdebdaf9 ("relay file read: start-pos fix")
Signed-off-by: Zhang Zhengming 
Reviewed-by: Zhao Lei 
Reviewed-by: Zhou Kete 
Reviewed-by: Pengcheng Yang 
Cc: Jens Axboe 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

relay: fix type mismatch when allocating memory in relay_create_buf()

2023-01-14T09:15:22+00:00

[ Upstream commit 4d8586e04602fe42f0a782d2005956f8b6302678 ]

The 'padding' field of the 'rchan_buf' structure is an array of 'size_t'
elements, but the memory is allocated for an array of 'size_t *' elements.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Link: https://lkml.kernel.org/r/20221129092002.3538384-1-Ilia.Gavrilov@infotecs.ru
Fixes: b86ff981a825 ("[PATCH] relay: migrate from relayfs to a generic relay API")
Signed-off-by: Ilia.Gavrilov 
Cc: Colin Ian King 
Cc: Jens Axboe 
Cc: wuchi 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

kernel/relay.c: drop unneeded initialization

2020-10-16T18:11:22+00:00

The variable 'consumed' is initialized with the consumed count but
immediately after that the consumed count is updated and assigned to
'consumed' again thus overwriting the previous value.  So, drop the
unneeded initialization.

Signed-off-by: Sudip Mukherjee 
Signed-off-by: Andrew Morton 
Reviewed-by: Andrew Morton 
Link: https://lkml.kernel.org/r/20201005205727.1147-1-sudipm.mukherjee@gmail.com
Signed-off-by: Linus Torvalds

kernel/relay.c: fix memleak on destroy relay channel

2020-08-21T16:52:53+00:00

kmemleak report memory leak as follows:

  unreferenced object 0x607ee4e5f948 (size 8):
  comm "syz-executor.1", pid 2098, jiffies 4295031601 (age 288.468s)
  hex dump (first 8 bytes):
  00 00 00 00 00 00 00 00 ........
  backtrace:
     relay_open kernel/relay.c:583 [inline]
     relay_open+0xb6/0x970 kernel/relay.c:563
     do_blk_trace_setup+0x4a8/0xb20 kernel/trace/blktrace.c:557
     __blk_trace_setup+0xb6/0x150 kernel/trace/blktrace.c:597
     blk_trace_ioctl+0x146/0x280 kernel/trace/blktrace.c:738
     blkdev_ioctl+0xb2/0x6a0 block/ioctl.c:613
     block_ioctl+0xe5/0x120 fs/block_dev.c:1871
     vfs_ioctl fs/ioctl.c:48 [inline]
     __do_sys_ioctl fs/ioctl.c:753 [inline]
     __se_sys_ioctl fs/ioctl.c:739 [inline]
     __x64_sys_ioctl+0x170/0x1ce fs/ioctl.c:739
     do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
     entry_SYSCALL_64_after_hwframe+0x44/0xa9

'chan->buf' is malloced in relay_open() by alloc_percpu() but not free
while destroy the relay channel.  Fix it by adding free_percpu() before
return from relay_destroy_channel().

Fixes: 017c59c042d0 ("relay: Use per CPU constructs for the relay channel buffer pointers")
Reported-by: Hulk Robot 
Signed-off-by: Wei Yongjun 
Signed-off-by: Andrew Morton 
Reviewed-by: Chris Wilson 
Cc: Al Viro 
Cc: Michael Ellerman 
Cc: David Rientjes 
Cc: Michel Lespinasse 
Cc: Daniel Axtens 
Cc: Thomas Gleixner 
Cc: Akash Goel 
Cc: 
Link: http://lkml.kernel.org/r/20200817122826.48518-1-weiyongjun1@huawei.com
Signed-off-by: Linus Torvalds

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Daniel Jordan 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Laurent Dufour 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds

kernel/relay.c: fix read_pos error when multiple readers

2020-06-05T02:06:26+00:00

When reading, read_pos should start with bytes_consumed, not file->f_pos.
Because when there is more than one reader, the read_pos corresponding to
file->f_pos may have been consumed, which will cause the data that has
been consumed to be read and the bytes_consumed update error.

Signed-off-by: Pengcheng Yang 
Signed-off-by: Andrew Morton 
Reviewed-by: Jens Axboe 
Cc: Greg Kroah-Hartman 
Cc: Jann Horn 
Cc: Al Viro e
Link: http://lkml.kernel.org/r/1579691175-28949-1-git-send-email-yangpc@wangsu.com
Signed-off-by: Linus Torvalds

kernel/relay.c: handle alloc_percpu returning NULL in relay_open

2020-06-05T02:06:26+00:00

alloc_percpu() may return NULL, which means chan->buf may be set to NULL.
In that case, when we do *per_cpu_ptr(chan->buf, ...), we dereference an
invalid pointer:

  BUG: Unable to handle kernel data access at 0x7dae0000
  Faulting instruction address: 0xc0000000003f3fec
  ...
  NIP relay_open+0x29c/0x600
  LR relay_open+0x270/0x600
  Call Trace:
     relay_open+0x264/0x600 (unreliable)
     __blk_trace_setup+0x254/0x600
     blk_trace_setup+0x68/0xa0
     sg_ioctl+0x7bc/0x2e80
     do_vfs_ioctl+0x13c/0x1300
     ksys_ioctl+0x94/0x130
     sys_ioctl+0x48/0xb0
     system_call+0x5c/0x68

Check if alloc_percpu returns NULL.

This was found by syzkaller both on x86 and powerpc, and the reproducer
it found on powerpc is capable of hitting the issue as an unprivileged
user.

Fixes: 017c59c042d0 ("relay: Use per CPU constructs for the relay channel buffer pointers")
Reported-by: syzbot+1e925b4b836afe85a1c6@syzkaller-ppc64.appspotmail.com
Reported-by: syzbot+587b2421926808309d21@syzkaller-ppc64.appspotmail.com
Reported-by: syzbot+58320b7171734bf79d26@syzkaller.appspotmail.com
Reported-by: syzbot+d6074fb08bdb2e010520@syzkaller.appspotmail.com
Signed-off-by: Daniel Axtens 
Signed-off-by: Andrew Morton 
Reviewed-by: Michael Ellerman 
Reviewed-by: Andrew Donnellan 
Acked-by: David Rientjes 
Cc: Akash Goel 
Cc: Andrew Donnellan 
Cc: Guenter Roeck 
Cc: Salvatore Bonaccorso 
Cc: 	[4.10+]
Link: http://lkml.kernel.org/r/20191219121256.26480-1-dja@axtens.net
Signed-off-by: Linus Torvalds

Merge branch 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2020-06-03T22:52:19+00:00

Pull splice updates from Al Viro:
 "Christoph's assorted splice cleanups"

* 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: rename pipe_buf ->steal to ->try_steal
  fs: make the pipe_buf_operations ->confirm operation optional
  fs: make the pipe_buf_operations ->steal operation optional
  trace: remove tracing_pipe_buf_ops
  pipe: merge anon_pipe_buf*_ops
  fs: simplify do_splice_from
  fs: simplify do_splice_to

fs: rename pipe_buf ->steal to ->try_steal

2020-05-20T16:14:10+00:00

And replace the arcane return value convention with a simple bool
where true means success and false means failure.

[AV: braino fix folded in]

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

fs: make the pipe_buf_operations ->confirm operation optional

2020-05-20T16:11:26+00:00

Just return 0 for success if it is not present.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro