In the Linux kernel, the following vulnerability has been resolved:
BPF: Fix potential bad pointer dereference in bpf_sys_bpf()
The bpf_sys_bpf() helper function allows an eBPF program to load another
eBPF program from within the kernel. In this case the argument union
bpf_attr pointer (as well as the insns and license pointers inside) is a
kernel address instead of a userspace address (which is the case of a
usual bpf() syscall). To make the memory copying process in the syscall
work in both cases, bpfptr_t was introduced to wrap around the pointer
and distinguish its origin. Specifically, when copying memory contents
from a bpfptr_t, a copy_from_user() is performed in case of a userspace
address and a memcpy() is performed for a kernel address.
This can lead to problems because the in-kernel pointer is never checked
for validity. The problem happens when an eBPF syscall program tries to
call bpf_sys_bpf() to load a program but provides a bad insns pointer --
say 0xdeadbeef -- in the bpf_attr union. The helper calls __sys_bpf()
which would then call bpf_prog_load() to load the program.
bpf_prog_load() is responsible for copying the eBPF instructions to the
newly allocated memory for the program; it creates a kernel bpfptr_t for
insns and invokes copy_from_bpfptr(). Internally, all bpfptr_t
operations are backed by the corresponding sockptr_t operations, which
performs direct memcpy() on kernel pointers for copy_from/strncpy_from
operations. Therefore, the code is always happy to dereference the bad
pointer to trigger a un-handle-able page fault and in turn an oops.
However, this is not supposed to happen because at that point the eBPF
program is already verified and should not cause a memory error.
Sample KASAN trace:
[ 25.685056][ T228] ==================================================================
[ 25.685680][ T228] BUG: KASAN: user-memory-access in copy_from_bpfptr+0x21/0x30
[ 25.686210][ T228] Read of size 80 at addr 00000000deadbeef by task poc/228
[ 25.686732][ T228]
[ 25.686893][ T228] CPU: 3 PID: 228 Comm: poc Not tainted 5.19.0-rc7 #7
[ 25.687375][ T228] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS d55cb5a 04/01/2014
[ 25.687991][ T228] Call Trace:
[ 25.688223][ T228] <TASK>
[ 25.688429][ T228] dump_stack_lvl+0x73/0x9e
[ 25.688747][ T228] print_report+0xea/0x200
[ 25.689061][ T228] ? copy_from_bpfptr+0x21/0x30
[ 25.689401][ T228] ? _printk+0x54/0x6e
[ 25.689693][ T228] ? _raw_spin_lock_irqsave+0x70/0xd0
[ 25.690071][ T228] ? copy_from_bpfptr+0x21/0x30
[ 25.690412][ T228] kasan_report+0xb5/0xe0
[ 25.690716][ T228] ? copy_from_bpfptr+0x21/0x30
[ 25.691059][ T228] kasan_check_range+0x2bd/0x2e0
[ 25.691405][ T228] ? copy_from_bpfptr+0x21/0x30
[ 25.691734][ T228] memcpy+0x25/0x60
[ 25.692000][ T228] copy_from_bpfptr+0x21/0x30
[ 25.692328][ T228] bpf_prog_load+0x604/0x9e0
[ 25.692653][ T228] ? cap_capable+0xb4/0xe0
[ 25.692956][ T228] ? security_capable+0x4f/0x70
[ 25.693324][ T228] __sys_bpf+0x3af/0x580
[ 25.693635][ T228] bpf_sys_bpf+0x45/0x240
[ 25.693937][ T228] bpf_prog_f0ec79a5a3caca46_bpf_func1+0xa2/0xbd
[ 25.694394][ T228] bpf_prog_run_pin_on_cpu+0x2f/0xb0
[ 25.694756][ T228] bpf_prog_test_run_syscall+0x146/0x1c0
[ 25.695144][ T228] bpf_prog_test_run+0x172/0x190
[ 25.695487][ T228] __sys_bpf+0x2c5/0x580
[ 25.695776][ T228] __x64_sys_bpf+0x3a/0x50
[ 25.696084][ T228] do_syscall_64+0x60/0x90
[ 25.696393][ T228] ? fpregs_assert_state_consistent+0x50/0x60
[ 25.696815][ T228] ? exit_to_user_mode_prepare+0x36/0xa0
[ 25.697202][ T228] ? syscall_exit_to_user_mode+0x20/0x40
[ 25.697586][ T228] ? do_syscall_64+0x6e/0x90
[ 25.697899][ T228] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 25.698312][ T228] RIP: 0033:0x7f6d543fb759
[ 25.698624][ T228] Code: 08 5b 89 e8 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
mptcp: move subflow cleanup in mptcp_destroy_common()
If the mptcp socket creation fails due to a CGROUP_INET_SOCK_CREATE
eBPF program, the MPTCP protocol ends-up leaking all the subflows:
the related cleanup happens in __mptcp_destroy_sock() that is not
invoked in such code path.
Address the issue moving the subflow sockets cleanup in the
mptcp_destroy_common() helper, which is invoked in every msk cleanup
path.
Additionally get rid of the intermediate list_splice_init step, which
is an unneeded relic from the past.
The issue is present since before the reported root cause commit, but
any attempt to backport the fix before that hash will require a complete
rewrite.
In the Linux kernel, the following vulnerability has been resolved:
iavf: Fix adminq error handling
iavf_alloc_asq_bufs/iavf_alloc_arq_bufs allocates with dma_alloc_coherent
memory for VF mailbox.
Free DMA regions for both ASQ and ARQ in case error happens during
configuration of ASQ/ARQ registers.
Without this change it is possible to see when unloading interface:
74626.583369: dma_debug_device_change: device driver has pending DMA allocations while released from device [count=32]
One of leaked entries details: [device address=0x0000000b27ff9000] [size=4096 bytes] [mapped with DMA_BIDIRECTIONAL] [mapped as coherent]
In the Linux kernel, the following vulnerability has been resolved:
ceph: don't leak snap_rwsem in handle_cap_grant
When handle_cap_grant is called on an IMPORT op, then the snap_rwsem is
held and the function is expected to release it before returning. It
currently fails to do that in all cases which could lead to a deadlock.
In the Linux kernel, the following vulnerability has been resolved:
octeontx2-af: Fix mcam entry resource leak
The teardown sequence in FLR handler returns if no NIX LF
is attached to PF/VF because it indicates that graceful
shutdown of resources already happened. But there is a
chance of all allocated MCAM entries not being freed by
PF/VF. Hence free mcam entries even in case of detached LF.
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: nomadik: Fix refcount leak in nmk_pinctrl_dt_subnode_to_map
of_parse_phandle() returns a node pointer with refcount
incremented, we should use of_node_put() on it when not need anymore.
Add missing of_node_put() to avoid refcount leak."
In the Linux kernel, the following vulnerability has been resolved:
net/sunrpc: fix potential memory leaks in rpc_sysfs_xprt_state_change()
The issue happens on some error handling paths. When the function
fails to grab the object `xprt`, it simply returns 0, forgetting to
decrease the reference count of another object `xps`, which is
increased by rpc_sysfs_xprt_kobj_get_xprt_switch(), causing refcount
leaks. Also, the function forgets to check whether `xps` is valid
before using it, which may result in NULL-dereferencing issues.
Fix it by adding proper error handling code when either `xprt` or
`xps` is NULL.