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An io_uring openat operation can update an audit reference count
from multiple threads resulting in the call trace below.
A call to io_uring_submit() with a single openat op with a flag of
IOSQE_ASYNC results in the following reference count updates.
These first part of the system call performs two increments that do not race.
do_syscall_64()
__do_sys_io_uring_enter()
io_submit_sqes()
io_openat_prep()
__io_openat_prep()
getname()
getname_flags() /* update 1 (increment) */
__audit_getname() /* update 2 (increment) */
The openat op is queued to an io_uring worker thread which starts the
opportunity for a race. The system call exit performs one decrement.
do_syscall_64()
syscall_exit_to_user_mode()
syscall_exit_to_user_mode_prepare()
__audit_syscall_exit()
audit_reset_context()
putname() /* update 3 (decrement) */
The io_uring worker thread performs one increment and two decrements.
These updates can race with the system call decrement.
io_wqe_worker()
io_worker_handle_work()
io_wq_submit_work()
io_issue_sqe()
io_openat()
io_openat2()
do_filp_open()
path_openat()
__audit_inode() /* update 4 (increment) */
putname() /* update 5 (decrement) */
__audit_uring_exit()
audit_reset_context()
putname() /* update 6 (decrement) */
The fix is to change the refcnt member of struct audit_names
from int to atomic_t.
kernel BUG at fs/namei.c:262!
Call Trace:
...
? putname+0x68/0x70
audit_reset_context.part.0.constprop.0+0xe1/0x300
__audit_uring_exit+0xda/0x1c0
io_issue_sqe+0x1f3/0x450
? lock_timer_base+0x3b/0xd0
io_wq_submit_work+0x8d/0x2b0
? __try_to_del_timer_sync+0x67/0xa0
io_worker_handle_work+0x17c/0x2b0
io_wqe_worker+0x10a/0x350
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/MW2PR2101MB1033FFF044A258F84AEAA584F1C9A@MW2PR2101MB1033.namprd21.prod.outlook.com/
Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Dan Clash <daclash@linux.microsoft.com>
Link: https://lore.kernel.org/r/20231012215518.GA4048@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking updates from Jakub Kicinski:
"Including fixes from netfilter and bpf.
Current release - regressions:
- eth: stmmac: fix failure to probe without MAC interface specified
Current release - new code bugs:
- docs: netlink: fix missing classic_netlink doc reference
Previous releases - regressions:
- deal with integer overflows in kmalloc_reserve()
- use sk_forward_alloc_get() in sk_get_meminfo()
- bpf_sk_storage: fix the missing uncharge in sk_omem_alloc
- fib: avoid warn splat in flow dissector after packet mangling
- skb_segment: call zero copy functions before using skbuff frags
- eth: sfc: check for zero length in EF10 RX prefix
Previous releases - always broken:
- af_unix: fix msg_controllen test in scm_pidfd_recv() for
MSG_CMSG_COMPAT
- xsk: fix xsk_build_skb() dereferencing possible ERR_PTR()
- netfilter:
- nft_exthdr: fix non-linear header modification
- xt_u32, xt_sctp: validate user space input
- nftables: exthdr: fix 4-byte stack OOB write
- nfnetlink_osf: avoid OOB read
- one more fix for the garbage collection work from last release
- igmp: limit igmpv3_newpack() packet size to IP_MAX_MTU
- bpf, sockmap: fix preempt_rt splat when using raw_spin_lock_t
- handshake: fix null-deref in handshake_nl_done_doit()
- ip: ignore dst hint for multipath routes to ensure packets are
hashed across the nexthops
- phy: micrel:
- correct bit assignments for cable test errata
- disable EEE according to the KSZ9477 errata
Misc:
- docs/bpf: document compile-once-run-everywhere (CO-RE) relocations
- Revert "net: macsec: preserve ingress frame ordering", it appears
to have been developed against an older kernel, problem doesn't
exist upstream"
* tag 'net-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (95 commits)
net: enetc: distinguish error from valid pointers in enetc_fixup_clear_rss_rfs()
Revert "net: team: do not use dynamic lockdep key"
net: hns3: remove GSO partial feature bit
net: hns3: fix the port information display when sfp is absent
net: hns3: fix invalid mutex between tc qdisc and dcb ets command issue
net: hns3: fix debugfs concurrency issue between kfree buffer and read
net: hns3: fix byte order conversion issue in hclge_dbg_fd_tcam_read()
net: hns3: Support query tx timeout threshold by debugfs
net: hns3: fix tx timeout issue
net: phy: Provide Module 4 KSZ9477 errata (DS80000754C)
netfilter: nf_tables: Unbreak audit log reset
netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c
netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction
netfilter: nf_tables: uapi: Describe NFTA_RULE_CHAIN_ID
netfilter: nfnetlink_osf: avoid OOB read
netfilter: nftables: exthdr: fix 4-byte stack OOB write
selftests/bpf: Check bpf_sk_storage has uncharged sk_omem_alloc
bpf: bpf_sk_storage: Fix the missing uncharge in sk_omem_alloc
bpf: bpf_sk_storage: Fix invalid wait context lockdep report
s390/bpf: Pass through tail call counter in trampolines
...
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Resetting rules' stateful data happens outside of the transaction logic,
so 'get' and 'dump' handlers have to emit audit log entries themselves.
Fixes: 8daa8fde3fc3f ("netfilter: nf_tables: Introduce NFT_MSG_GETRULE_RESET")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Since set element reset is not integrated into nf_tables' transaction
logic, an explicit log call is needed, similar to NFT_MSG_GETOBJ_RESET
handling.
For the sake of simplicity, catchall element reset will always generate
a dedicated log entry. This relieves nf_tables_dump_set() from having to
adjust the logged element count depending on whether a catchall element
was found or not.
Fixes: 079cd633219d7 ("netfilter: nf_tables: Introduce NFT_MSG_GETSETELEM_RESET")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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The patch fixes following checkpatch.pl issue:
ERROR: open brace '{' following function definitions go on the next line
ERROR: do not use assignment in if condition
Signed-off-by: Atul Kumar Pant <atulpant.linux@gmail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Fixes following checkpatch.pl issue:
ERROR: space required before the open parenthesis '('
ERROR: spaces required around that '='
ERROR: spaces required around that '<'
ERROR: spaces required around that '=='
Signed-off-by: Atul Kumar Pant <atulpant.linux@gmail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Tracefs or debugfs maybe cause hundreds to thousands of PATH records,
too many PATH records maybe cause soft lockup.
For example:
1. CONFIG_KASAN=y && CONFIG_PREEMPTION=n
2. auditctl -a exit,always -S open -k key
3. sysctl -w kernel.watchdog_thresh=5
4. mkdir /sys/kernel/debug/tracing/instances/test
There may be a soft lockup as follows:
watchdog: BUG: soft lockup - CPU#45 stuck for 7s! [mkdir:15498]
Kernel panic - not syncing: softlockup: hung tasks
Call trace:
dump_backtrace+0x0/0x30c
show_stack+0x20/0x30
dump_stack+0x11c/0x174
panic+0x27c/0x494
watchdog_timer_fn+0x2bc/0x390
__run_hrtimer+0x148/0x4fc
__hrtimer_run_queues+0x154/0x210
hrtimer_interrupt+0x2c4/0x760
arch_timer_handler_phys+0x48/0x60
handle_percpu_devid_irq+0xe0/0x340
__handle_domain_irq+0xbc/0x130
gic_handle_irq+0x78/0x460
el1_irq+0xb8/0x140
__audit_inode_child+0x240/0x7bc
tracefs_create_file+0x1b8/0x2a0
trace_create_file+0x18/0x50
event_create_dir+0x204/0x30c
__trace_add_new_event+0xac/0x100
event_trace_add_tracer+0xa0/0x130
trace_array_create_dir+0x60/0x140
trace_array_create+0x1e0/0x370
instance_mkdir+0x90/0xd0
tracefs_syscall_mkdir+0x68/0xa0
vfs_mkdir+0x21c/0x34c
do_mkdirat+0x1b4/0x1d4
__arm64_sys_mkdirat+0x4c/0x60
el0_svc_common.constprop.0+0xa8/0x240
do_el0_svc+0x8c/0xc0
el0_svc+0x20/0x30
el0_sync_handler+0xb0/0xb4
el0_sync+0x160/0x180
Therefore, we add cond_resched() to __audit_inode_child() to fix it.
Fixes: 5195d8e217a7 ("audit: dynamically allocate audit_names when not enough space is in the names array")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Back in 2008 we extended the capability bits from 32 to 64, and we did
it by extending the single 32-bit capability word from one word to an
array of two words. It was then obfuscated by hiding the "2" behind two
macro expansions, with the reasoning being that maybe it gets extended
further some day.
That reasoning may have been valid at the time, but the last thing we
want to do is to extend the capability set any more. And the array of
values not only causes source code oddities (with loops to deal with
it), but also results in worse code generation. It's a lose-lose
situation.
So just change the 'u32[2]' into a 'u64' and be done with it.
We still have to deal with the fact that the user space interface is
designed around an array of these 32-bit values, but that was the case
before too, since the array layouts were different (ie user space
doesn't use an array of 32-bit values for individual capability masks,
but an array of 32-bit slices of multiple masks).
So that marshalling of data is actually simplified too, even if it does
remain somewhat obscure and odd.
This was all triggered by my reaction to the new "cap_isidentical()"
introduced recently. By just using a saner data structure, it went from
unsigned __capi;
CAP_FOR_EACH_U32(__capi) {
if (a.cap[__capi] != b.cap[__capi])
return false;
}
return true;
to just being
return a.val == b.val;
instead. Which is rather more obvious both to humans and to compilers.
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify updates from Jan Kara:
"Support for auditing decisions regarding fanotify permission events"
* tag 'fsnotify_for_v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fanotify,audit: Allow audit to use the full permission event response
fanotify: define struct members to hold response decision context
fanotify: Ensure consistent variable type for response
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This patch passes the full response so that the audit function can use all
of it. The audit function was updated to log the additional information in
the AUDIT_FANOTIFY record.
Currently the only type of fanotify info that is defined is an audit
rule number, but convert it to hex encoding to future-proof the field.
Hex encoding suggested by Paul Moore <paul@paul-moore.com>.
The {subj,obj}_trust values are {0,1,2}, corresponding to no, yes, unknown.
Sample records:
type=FANOTIFY msg=audit(1600385147.372:590): resp=2 fan_type=1 fan_info=3137 subj_trust=3 obj_trust=5
type=FANOTIFY msg=audit(1659730979.839:284): resp=1 fan_type=0 fan_info=0 subj_trust=2 obj_trust=2
Suggested-by: Steve Grubb <sgrubb@redhat.com>
Link: https://lore.kernel.org/r/3075502.aeNJFYEL58@x2
Tested-by: Steve Grubb <sgrubb@redhat.com>
Acked-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <bcb6d552e517b8751ece153e516d8b073459069c.1675373475.git.rgb@redhat.com>
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The user space API for the response variable is __u32. This patch makes
sure that the whole path through the kernel uses u32 so that there is
no sign extension or truncation of the user space response.
Suggested-by: Steve Grubb <sgrubb@redhat.com>
Link: https://lore.kernel.org/r/12617626.uLZWGnKmhe@x2
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Tested-by: Steve Grubb <sgrubb@redhat.com>
Acked-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <3778cb0b3501bc4e686ba7770b20eb9ab0506cf4.1675373475.git.rgb@redhat.com>
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Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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audit_filter_uring(), audit_filter_inode_name() are substantially
similar to audit_filter_syscall(). Move the core logic to
__audit_filter_op() which can be parametrized for all three.
On a Skylakex system, getpid() latency (all results aggregated
across 12 boot cycles):
Min Mean Median Max pstdev
(ns) (ns) (ns) (ns)
- 196.63 207.86 206.60 230.98 (+- 3.92%)
+ 183.73 196.95 192.31 232.49 (+- 6.04%)
Performance counter stats for 'bin/getpid' (3 runs) go from:
cycles 805.58 ( +- 4.11% )
instructions 1654.11 ( +- .05% )
IPC 2.06 ( +- 3.39% )
branches 430.02 ( +- .05% )
branch-misses 1.55 ( +- 7.09% )
L1-dcache-loads 440.01 ( +- .09% )
L1-dcache-load-misses 9.05 ( +- 74.03% )
to:
cycles 765.37 ( +- 6.66% )
instructions 1677.07 ( +- 0.04% )
IPC 2.20 ( +- 5.90% )
branches 431.10 ( +- 0.04% )
branch-misses 1.60 ( +- 11.25% )
L1-dcache-loads 521.04 ( +- 0.05% )
L1-dcache-load-misses 6.92 ( +- 77.60% )
(Both aggregated over 12 boot cycles.)
The increased L1-dcache-loads are due to some intermediate values now
coming from the stack.
The improvement in cycles is due to a slightly denser loop (the list
parameter in the list_for_each_entry_rcu() exit check now comes from
a register rather than a constant as before.)
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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ctx->major contains the current syscall number. This is, of course, a
constant for the duration of the syscall. Unfortunately, GCC's alias
analysis cannot prove that it is not modified via a pointer in the
audit_filter_syscall() loop, and so always loads it from memory.
In and of itself the load isn't very expensive (ops dependent on the
ctx->major load are only used to determine the direction of control flow
and have short dependence chains and, in any case the related branches
get predicted perfectly in the fastpath) but still cache ctx->major
in a local for two reasons:
* ctx->major is in the first cacheline of struct audit_context and has
similar alignment as audit_entry::list audit_entry. For cases
with a lot of audit rules, doing this reduces one source of contention
from a potentially busy cache-set.
* audit_in_mask() (called in the hot loop in audit_filter_syscall())
does cast manipulation and error checking on ctx->major:
audit_in_mask(const struct audit_krule *rule, unsigned long val):
if (val > 0xffffffff)
return false;
word = AUDIT_WORD(val);
if (word >= AUDIT_BITMASK_SIZE)
return false;
bit = AUDIT_BIT(val);
return rule->mask[word] & bit;
The clauses related to the rule need to be evaluated in the loop, but
the rest is unnecessarily re-evaluated for every loop iteration.
(Note, however, that most of these are cheap ALU ops and the branches
are perfectly predicted. However, see discussion on cycles
improvement below for more on why it is still worth hoisting.)
On a Skylakex system change in getpid() latency (aggregated over
12 boot cycles):
Min Mean Median Max pstdev
(ns) (ns) (ns) (ns)
- 201.30 216.14 216.22 228.46 (+- 1.45%)
+ 196.63 207.86 206.60 230.98 (+- 3.92%)
Performance counter stats for 'bin/getpid' (3 runs) go from:
cycles 836.89 ( +- .80% )
instructions 2000.19 ( +- .03% )
IPC 2.39 ( +- .83% )
branches 430.14 ( +- .03% )
branch-misses 1.48 ( +- 3.37% )
L1-dcache-loads 471.11 ( +- .05% )
L1-dcache-load-misses 7.62 ( +- 46.98% )
to:
cycles 805.58 ( +- 4.11% )
instructions 1654.11 ( +- .05% )
IPC 2.06 ( +- 3.39% )
branches 430.02 ( +- .05% )
branch-misses 1.55 ( +- 7.09% )
L1-dcache-loads 440.01 ( +- .09% )
L1-dcache-load-misses 9.05 ( +- 74.03% )
(Both aggregated over 12 boot cycles.)
instructions: we reduce around 8 instructions/iteration because some of
the computation is now hoisted out of the loop (branch count does not
change because GCC, for reasons unclear, only hoists the computations
while keeping the basic-blocks.)
cycles: improve by about 5% (in aggregate and looking at individual run
numbers.) This is likely because we now waste fewer pipeline resources
on unnecessary instructions which allows the control flow to
speculatively execute further ahead shortening the execution of the loop
a little. The final gating factor on the performance of this loop
remains the long dependence chain due to the linked-list load.
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit
Pull audit updates from Paul Moore:
"Six audit patches for v6.1, most are pretty trivial, but a quick list
of the highlights are below:
- Only free the audit proctitle information on task exit. This allows
us to cache the information and improve performance slightly.
- Use the time_after() macro to do time comparisons instead of doing
it directly and potentially causing ourselves problems when the
timer wraps.
- Convert an audit_context state comparison from a relative enum
comparison, e.g. (x < y), to a not-equal comparison to ensure that
we are not caught out at some unknown point in the future by an
enum shuffle.
- A handful of small cleanups such as tidying up comments and
removing unused declarations"
* tag 'audit-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: remove selinux_audit_rule_update() declaration
audit: use time_after to compare time
audit: free audit_proctitle only on task exit
audit: explicitly check audit_context->context enum value
audit: audit_context pid unused, context enum comment fix
audit: fix repeated words in comments
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Since audit_proctitle is generated at syscall exit time, its value is
used immediately and cached for the next syscall. Since this is the
case, then only clear it at task exit time. Otherwise, there is no
point in caching the value OR bearing the overhead of regenerating it.
Fixes: 12c5e81d3fd0 ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Be explicit in checking the struct audit_context "context" member enum
value rather than assuming the order of context enum values.
Fixes: 12c5e81d3fd0 ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The pid member of struct audit_context is never used. Remove it.
The audit_reset_context() comment about unconditionally resetting
"ctx->state" should read "ctx->context".
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The success and return_code are needed by the filters. Move
audit_return_fixup() before the filters. This was causing syscall
auditing events to be missed.
Link: https://github.com/linux-audit/audit-kernel/issues/138
Cc: stable@vger.kernel.org
Fixes: 12c5e81d3fd0 ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: manual merge required]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Delete the redundant word 'doesn't'.
Signed-off-by: Jilin Yuan <yuanjilin@cdjrlc.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Currently @audit_context is allocated twice for io_uring workers:
1. copy_process() calls audit_alloc();
2. io_sq_thread() or io_wqe_worker() calls audit_alloc_kernel() (which
is effectively audit_alloc()) and overwrites @audit_context,
causing:
BUG: memory leak
unreferenced object 0xffff888144547400 (size 1024):
<...>
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff8135cfc3>] audit_alloc+0x133/0x210
[<ffffffff81239e63>] copy_process+0xcd3/0x2340
[<ffffffff8123b5f3>] create_io_thread+0x63/0x90
[<ffffffff81686604>] create_io_worker+0xb4/0x230
[<ffffffff81686f68>] io_wqe_enqueue+0x248/0x3b0
[<ffffffff8167663a>] io_queue_iowq+0xba/0x200
[<ffffffff816768b3>] io_queue_async+0x113/0x180
[<ffffffff816840df>] io_req_task_submit+0x18f/0x1a0
[<ffffffff816841cd>] io_apoll_task_func+0xdd/0x120
[<ffffffff8167d49f>] tctx_task_work+0x11f/0x570
[<ffffffff81272c4e>] task_work_run+0x7e/0xc0
[<ffffffff8125a688>] get_signal+0xc18/0xf10
[<ffffffff8111645b>] arch_do_signal_or_restart+0x2b/0x730
[<ffffffff812ea44e>] exit_to_user_mode_prepare+0x5e/0x180
[<ffffffff844ae1b2>] syscall_exit_to_user_mode+0x12/0x20
[<ffffffff844a7e80>] do_syscall_64+0x40/0x80
Then,
3. io_sq_thread() or io_wqe_worker() frees @audit_context using
audit_free();
4. do_exit() eventually calls audit_free() again, which is okay
because audit_free() does a NULL check.
As suggested by Paul Moore, fix it by deleting audit_alloc_kernel() and
redundant audit_free() calls.
Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Suggested-by: Paul Moore <paul@paul-moore.com>
Cc: stable@vger.kernel.org
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20220803222343.31673-1-yepeilin.cs@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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|
Reset the type of the record last as the helper `audit_free_module()`
depends on it.
unreferenced object 0xffff888153b707f0 (size 16):
comm "modprobe", pid 1319, jiffies 4295110033 (age 1083.016s)
hex dump (first 16 bytes):
62 69 6e 66 6d 74 5f 6d 69 73 63 00 6b 6b 6b a5 binfmt_misc.kkk.
backtrace:
[<ffffffffa07dbf9b>] kstrdup+0x2b/0x50
[<ffffffffa04b0a9d>] __audit_log_kern_module+0x4d/0xf0
[<ffffffffa03b6664>] load_module+0x9d4/0x2e10
[<ffffffffa03b8f44>] __do_sys_finit_module+0x114/0x1b0
[<ffffffffa1f47124>] do_syscall_64+0x34/0x80
[<ffffffffa200007e>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
Cc: stable@vger.kernel.org
Fixes: 12c5e81d3fd0 ("audit: prepare audit_context for use in calling contexts beyond syscalls")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Not calling the function for dummy contexts will cause the context to
not be reset. During the next syscall, this will cause an error in
__audit_syscall_entry:
WARN_ON(context->context != AUDIT_CTX_UNUSED);
WARN_ON(context->name_count);
if (context->context != AUDIT_CTX_UNUSED || context->name_count) {
audit_panic("unrecoverable error in audit_syscall_entry()");
return;
}
These problematic dummy contexts are created via the following call
chain:
exit_to_user_mode_prepare
-> arch_do_signal_or_restart
-> get_signal
-> task_work_run
-> tctx_task_work
-> io_req_task_submit
-> io_issue_sqe
-> audit_uring_entry
Cc: stable@vger.kernel.org
Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Julian Orth <ju.orth@gmail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit
Pull audit update from Paul Moore:
"Just one audit patch queued for v5.18:
- Change the AUDIT_TIME_* record generation so that they are
generated at syscall exit time and subject to all of the normal
syscall exit filtering.
This should help reduce noise and ensure those records which are
most relevant to the admin's audit configuration are recorded in
the audit log"
* tag 'audit-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: log AUDIT_TIME_* records only from rules
|
|
AUDIT_TIME_* events are generated when there are syscall rules present
that are not related to time keeping. This will produce noisy log
entries that could flood the logs and hide events we really care about.
Rather than immediately produce the AUDIT_TIME_* records, store the data
in the context and log it at syscall exit time respecting the filter
rules.
Note: This eats the audit_buffer, unlike any others in show_special().
Please see https://bugzilla.redhat.com/show_bug.cgi?id=1991919
Fixes: 7e8eda734d30 ("ntp: Audit NTP parameters adjustment")
Fixes: 2d87a0674bd6 ("timekeeping: Audit clock adjustments")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: fixed style/whitespace issues]
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
As reported by Jeff, dereferencing the openat2 syscall argument in
audit_match_perm() to obtain the open_how::flags can result in an
oops/page-fault. This patch fixes this by using the open_how struct
that we store in the audit_context with audit_openat2_how().
Independent of this patch, Richard Guy Briggs posted a similar patch
to the audit mailing list roughly 40 minutes after this patch was
posted.
Cc: stable@vger.kernel.org
Fixes: 1c30e3af8a79 ("audit: add support for the openat2 syscall")
Reported-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
The security_task_getsecid_subj() LSM hook invites misuse by allowing
callers to specify a task even though the hook is only safe when the
current task is referenced. Fix this by removing the task_struct
argument to the hook, requiring LSM implementations to use the
current task. While we are changing the hook declaration we also
rename the function to security_current_getsecid_subj() in an effort
to reinforce that the hook captures the subjective credentials of the
current task and not an arbitrary task on the system.
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit
Pull audit updates from Paul Moore:
"Add some additional audit logging to capture the openat2() syscall
open_how struct info.
Previous variations of the open()/openat() syscalls allowed audit
admins to inspect the syscall args to get the information contained in
the new open_how struct used in openat2()"
* tag 'audit-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: return early if the filter rule has a lower priority
audit: add OPENAT2 record to list "how" info
audit: add support for the openat2 syscall
audit: replace magic audit syscall class numbers with macros
lsm_audit: avoid overloading the "key" audit field
audit: Convert to SPDX identifier
audit: rename struct node to struct audit_node to prevent future name collisions
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
- Add LSM/SELinux/Smack controls and auditing for io-uring.
As usual, the individual commit descriptions have more detail, but we
were basically missing two things which we're adding here:
+ establishment of a proper audit context so that auditing of
io-uring ops works similarly to how it does for syscalls (with
some io-uring additions because io-uring ops are *not* syscalls)
+ additional LSM hooks to enable access control points for some of
the more unusual io-uring features, e.g. credential overrides.
The additional audit callouts and LSM hooks were done in conjunction
with the io-uring folks, based on conversations and RFC patches
earlier in the year.
- Fixup the binder credential handling so that the proper credentials
are used in the LSM hooks; the commit description and the code
comment which is removed in these patches are helpful to understand
the background and why this is the proper fix.
- Enable SELinux genfscon policy support for securityfs, allowing
improved SELinux filesystem labeling for other subsystems which make
use of securityfs, e.g. IMA.
* tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
security: Return xattr name from security_dentry_init_security()
selinux: fix a sock regression in selinux_ip_postroute_compat()
binder: use cred instead of task for getsecid
binder: use cred instead of task for selinux checks
binder: use euid from cred instead of using task
LSM: Avoid warnings about potentially unused hook variables
selinux: fix all of the W=1 build warnings
selinux: make better use of the nf_hook_state passed to the NF hooks
selinux: fix race condition when computing ocontext SIDs
selinux: remove unneeded ipv6 hook wrappers
selinux: remove the SELinux lockdown implementation
selinux: enable genfscon labeling for securityfs
Smack: Brutalist io_uring support
selinux: add support for the io_uring access controls
lsm,io_uring: add LSM hooks to io_uring
io_uring: convert io_uring to the secure anon inode interface
fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure()
audit: add filtering for io_uring records
audit,io_uring,io-wq: add some basic audit support to io_uring
audit: prepare audit_context for use in calling contexts beyond syscalls
|
|
It is not necessary for audit_filter_rules() functions to check
audit fileds of the rule with a lower priority, and if we did,
there might be some unintended effects, such as the ctx->ppid
may be changed unexpectedly, so return early if the rule has
a lower priority.
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
[PM: slight tweak to the subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Fix possible null-pointer dereference in audit_filter_rules.
audit_filter_rules() error: we previously assumed 'ctx' could be null
Cc: stable@vger.kernel.org
Fixes: bf361231c295 ("audit: add saddr_fam filter field")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Since the openat2(2) syscall uses a struct open_how pointer to communicate
its parameters they are not usefully recorded by the audit SYSCALL record's
four existing arguments.
Add a new audit record type OPENAT2 that reports the parameters in its
third argument, struct open_how with fields oflag, mode and resolve.
The new record in the context of an event would look like:
time->Wed Mar 17 16:28:53 2021
type=PROCTITLE msg=audit(1616012933.531:184): proctitle=
73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D
7465737473756974652D737641440066696C652D6F70656E617432
type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2"
inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00
obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE
cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
type=PATH msg=audit(1616012933.531:184):
item=0 name="/root/rgb/git/audit-testsuite/tests"
inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00
obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT
cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
type=CWD msg=audit(1616012933.531:184):
cwd="/root/rgb/git/audit-testsuite/tests"
type=OPENAT2 msg=audit(1616012933.531:184):
oflag=0100302 mode=0600 resolve=0xa
type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437
success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18
items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0
fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2"
exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2"
subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
key="testsuite-1616012933-bjAUcEPO"
Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@redhat.com
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
[PM: tweak subject, wrap example, move AUDIT_OPENAT2 to 1337]
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
The openat2(2) syscall was added in kernel v5.6 with commit
fddb5d430ad9 ("open: introduce openat2(2) syscall").
Add the openat2(2) syscall to the audit syscall classifier.
Link: https://github.com/linux-audit/audit-kernel/issues/67
Link: https://lore.kernel.org/r/f5f1a4d8699613f8c02ce762807228c841c2e26f.1621363275.git.rgb@redhat.com
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
[PM: merge fuzz due to previous header rename, commit line wraps]
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Replace audit syscall class magic numbers with macros.
This required putting the macros into new header file
include/linux/audit_arch.h since the syscall macros were
included for both 64 bit and 32 bit in any compat code, causing
redefinition warnings.
Link: https://lore.kernel.org/r/2300b1083a32aade7ae7efb95826e8f3f260b1df.1621363275.git.rgb@redhat.com
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
[PM: renamed header to audit_arch.h after consulting with Richard]
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
This patch adds basic audit io_uring filtering, using as much of the
existing audit filtering infrastructure as possible. In order to do
this we reuse the audit filter rule's syscall mask for the io_uring
operation and we create a new filter for io_uring operations as
AUDIT_FILTER_URING_EXIT/audit_filter_list[7].
Thanks to Richard Guy Briggs for his review, feedback, and work on
the corresponding audit userspace changes.
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
This patch adds basic auditing to io_uring operations, regardless of
their context. This is accomplished by allocating audit_context
structures for the io-wq worker and io_uring SQPOLL kernel threads
as well as explicitly auditing the io_uring operations in
io_issue_sqe(). Individual io_uring operations can bypass auditing
through the "audit_skip" field in the struct io_op_def definition for
the operation; although great care must be taken so that security
relevant io_uring operations do not bypass auditing; please contact
the audit mailing list (see the MAINTAINERS file) with any questions.
The io_uring operations are audited using a new AUDIT_URINGOP record,
an example is shown below:
type=UNKNOWN[1336] msg=audit(1631800225.981:37289):
uring_op=19 success=yes exit=0 items=0 ppid=15454 pid=15681
uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
key=(null)
Thanks to Richard Guy Briggs for review and feedback.
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
This patch cleans up some of our audit_context handling by
abstracting out the reset and return code fixup handling to dedicated
functions. Not only does this help make things easier to read and
inspect, it allows for easier reuse by future patches. We also
convert the simple audit_context->in_syscall flag into an enum which
can be used to by future patches to indicate a calling context other
than the syscall context.
Thanks to Richard Guy Briggs for review and feedback.
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Use SPDX-License-Identifier instead of a verbose license text.
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Run the following command to find and remove the trailing spaces and tabs:
sed -r -i 's/[ \t]+$//' <audit_files>
The files to be checked are as follows:
kernel/audit*
include/linux/audit.h
include/uapi/linux/audit.h
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
AUDIT_DISABLED defined in kernel/audit.h as element of enum audit_state
and redefined in kernel/audit.c. This produces a warning when kernel builds
with syscalls audit disabled and brokes kernel build if -Werror used.
enum audit_state used in syscall audit code only. This patch changes
enum audit_state constants prefix AUDIT to AUDIT_STATE to avoid
AUDIT_DISABLED redefinition.
Signed-off-by: Sergey Nazarov <s-nazarov@yandex.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Fix the following checkpatch warning in auditsc.c:
WARNING: Missing a blank line after declarations
Signed-off-by: Roni Nevalainen <kitten@kittenz.dev>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit
Pull audit updates from Paul Moore:
"Another small pull request for audit, most of the patches are
documentation updates with only two real code changes: one to fix a
compiler warning for a dummy function/macro, and one to cleanup some
code since we removed the AUDIT_FILTER_ENTRY ages ago (v4.17)"
* tag 'audit-pr-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: drop /proc/PID/loginuid documentation Format field
audit: avoid -Wempty-body warning
audit: document /proc/PID/sessionid
audit: document /proc/PID/loginuid
MAINTAINERS: update audit files
audit: further cleanup of AUDIT_FILTER_ENTRY deprecation
|
|
Of the three LSMs that implement the security_task_getsecid() LSM
hook, all three LSMs provide the task's objective security
credentials. This turns out to be unfortunate as most of the hook's
callers seem to expect the task's subjective credentials, although
a small handful of callers do correctly expect the objective
credentials.
This patch is the first step towards fixing the problem: it splits
the existing security_task_getsecid() hook into two variants, one
for the subjective creds, one for the objective creds.
void security_task_getsecid_subj(struct task_struct *p,
u32 *secid);
void security_task_getsecid_obj(struct task_struct *p,
u32 *secid);
While this patch does fix all of the callers to use the correct
variant, in order to keep this patch focused on the callers and to
ease review, the LSMs continue to use the same implementation for
both hooks. The net effect is that this patch should not change
the behavior of the kernel in any way, it will be up to the latter
LSM specific patches in this series to change the hook
implementations and return the correct credentials.
Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA)
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
Remove the list parameter from the function call since the exit filter
list is the only remaining list used by this function.
This cleans up commit 5260ecc2e048
("audit: deprecate the AUDIT_FILTER_ENTRY filter")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
https://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
https://git.kernel.org/brauner/man-pages/c/1d7b902e2875a1ff342e036a9f866a995640aea8
In order to support idmapped mounts, filesystems need to be changed
and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
patches to convert individual filesystem are not very large or
complicated overall as can be seen from the included fat, ext4, and
xfs ports. Patches for other filesystems are actively worked on and
will be sent out separately. The xfstestsuite can be used to verify
that port has been done correctly.
The mount_setattr() syscall is motivated independent of the idmapped
mounts patches and it's been around since July 2019. One of the most
valuable features of the new mount api is the ability to perform
mounts based on file descriptors only.
Together with the lookup restrictions available in the openat2()
RESOLVE_* flag namespace which we added in v5.6 this is the first time
we are close to hardened and race-free (e.g. symlinks) mounting and
path resolution.
While userspace has started porting to the new mount api to mount
proper filesystems and create new bind-mounts it is currently not
possible to change mount options of an already existing bind mount in
the new mount api since the mount_setattr() syscall is missing.
With the addition of the mount_setattr() syscall we remove this last
restriction and userspace can now fully port to the new mount api,
covering every use-case the old mount api could. We also add the
crucial ability to recursively change mount options for a whole mount
tree, both removing and adding mount options at the same time. This
syscall has been requested multiple times by various people and
projects.
There is a simple tool available at
https://github.com/brauner/mount-idmapped
that allows to create idmapped mounts so people can play with this
patch series. I'll add support for the regular mount binary should you
decide to pull this in the following weeks:
Here's an example to a simple idmapped mount of another user's home
directory:
u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt
u1001@f2-vm:/$ ls -al /home/ubuntu/
total 28
drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
drwxr-xr-x 4 root root 4096 Oct 28 04:00 ..
-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile
-rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ ls -al /mnt/
total 28
drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 .
drwxr-xr-x 29 root root 4096 Oct 28 22:01 ..
-rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile
-rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ touch /mnt/my-file
u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file
u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file
u1001@f2-vm:/$ ls -al /mnt/my-file
-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file
u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file
u1001@f2-vm:/$ getfacl /mnt/my-file
getfacl: Removing leading '/' from absolute path names
# file: mnt/my-file
# owner: u1001
# group: u1001
user::rw-
user:u1001:rwx
group::rw-
mask::rwx
other::r--
u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
getfacl: Removing leading '/' from absolute path names
# file: home/ubuntu/my-file
# owner: ubuntu
# group: ubuntu
user::rw-
user:ubuntu:rwx
group::rw-
mask::rwx
other::r--"
* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
xfs: support idmapped mounts
ext4: support idmapped mounts
fat: handle idmapped mounts
tests: add mount_setattr() selftests
fs: introduce MOUNT_ATTR_IDMAP
fs: add mount_setattr()
fs: add attr_flags_to_mnt_flags helper
fs: split out functions to hold writers
namespace: only take read lock in do_reconfigure_mnt()
mount: make {lock,unlock}_mount_hash() static
namespace: take lock_mount_hash() directly when changing flags
nfs: do not export idmapped mounts
overlayfs: do not mount on top of idmapped mounts
ecryptfs: do not mount on top of idmapped mounts
ima: handle idmapped mounts
apparmor: handle idmapped mounts
fs: make helpers idmap mount aware
exec: handle idmapped mounts
would_dump: handle idmapped mounts
...
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No invoker uses the return value of audit_filter_syscall().
So make it return void, and amend the comment of
audit_filter_syscall().
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
[PM: removed the changelog from the description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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When interacting with user namespace and non-user namespace aware
filesystem capabilities the vfs will perform various security checks to
determine whether or not the filesystem capabilities can be used by the
caller, whether they need to be removed and so on. The main
infrastructure for this resides in the capability codepaths but they are
called through the LSM security infrastructure even though they are not
technically an LSM or optional. This extends the existing security hooks
security_inode_removexattr(), security_inode_killpriv(),
security_inode_getsecurity() to pass down the mount's user namespace and
makes them aware of idmapped mounts.
In order to actually get filesystem capabilities from disk the
capability infrastructure exposes the get_vfs_caps_from_disk() helper.
For user namespace aware filesystem capabilities a root uid is stored
alongside the capabilities.
In order to determine whether the caller can make use of the filesystem
capability or whether it needs to be ignored it is translated according
to the superblock's user namespace. If it can be translated to uid 0
according to that id mapping the caller can use the filesystem
capabilities stored on disk. If we are accessing the inode that holds
the filesystem capabilities through an idmapped mount we map the root
uid according to the mount's user namespace. Afterwards the checks are
identical to non-idmapped mounts: reading filesystem caps from disk
enforces that the root uid associated with the filesystem capability
must have a mapping in the superblock's user namespace and that the
caller is either in the same user namespace or is a descendant of the
superblock's user namespace. For filesystems that are mountable inside
user namespace the caller can just mount the filesystem and won't
usually need to idmap it. If they do want to idmap it they can create an
idmapped mount and mark it with a user namespace they created and which
is thus a descendant of s_user_ns. For filesystems that are not
mountable inside user namespaces the descendant rule is trivially true
because the s_user_ns will be the initial user namespace.
If the initial user namespace is passed nothing changes so non-idmapped
mounts will see identical behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-11-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit
Pull audit updates from Paul Moore:
"A small set of audit patches for v5.11 with four patches in total and
only one of any real significance.
Richard's patch to trigger accompanying records causes the kernel to
emit additional related records when an audit event occurs; helping
provide some much needed context to events in the audit log. It is
also worth mentioning that this is a revised patch based on an earlier
attempt that had to be reverted in the v5.8 time frame.
Everything passes our test suite, and with no problems reported please
merge this for v5.11"
* tag 'audit-pr-20201214' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: replace atomic_add_return()
audit: fix macros warnings
audit: trigger accompanying records when no rules present
audit: fix a kernel-doc markup
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Some unused macros could cause gcc warning:
kernel/audit.c:68:0: warning: macro "AUDIT_UNINITIALIZED" is not used
[-Wunused-macros]
kernel/auditsc.c:104:0: warning: macro "AUDIT_AUX_IPCPERM" is not used
[-Wunused-macros]
kernel/auditsc.c:82:0: warning: macro "AUDITSC_INVALID" is not used
[-Wunused-macros]
AUDIT_UNINITIALIZED and AUDITSC_INVALID are still meaningful and should
be in incorporated.
Just remove AUDIT_AUX_IPCPERM.
Thanks comments from Richard Guy Briggs and Paul Moore.
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Richard Guy Briggs <rgb@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: linux-audit@redhat.com
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Paul Moore <paul@paul-moore.com>
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On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.
Define SYSCALL_WORK_SYSCALL_AUDIT, use it in the generic entry code and
convert the code which uses the TIF specific helper functions to use the
new *_syscall_work() helpers which either resolve to the new mode for users
of the generic entry code or to the TIF based functions for the other
architectures.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-9-krisman@collabora.com
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