Using parent->regs[] when propagating REG_LIVE_READ for spilled regs
doesn't work since parent->regs[] denote the set of normal registers
but not spilled ones. Propagate to the correct regs.
Fixes: dc503a8ad9 ("bpf/verifier: track liveness for pruning")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Resolve issues with !CONFIG_BPF_SYSCALL and !STREAM_PARSER
net/core/filter.c: In function ‘do_sk_redirect_map’:
net/core/filter.c:1881:3: error: implicit declaration of function ‘__sock_map_lookup_elem’ [-Werror=implicit-function-declaration]
sk = __sock_map_lookup_elem(ri->map, ri->ifindex);
^
net/core/filter.c:1881:6: warning: assignment makes pointer from integer without a cast [enabled by default]
sk = __sock_map_lookup_elem(ri->map, ri->ifindex);
Fixes: 174a79ff95 ("bpf: sockmap with sk redirect support")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
psock will uninitialized in default case we need to do the same psock lookup
and check as in other branch. Fixes compile warning below.
kernel/bpf/sockmap.c: In function ‘smap_state_change’:
kernel/bpf/sockmap.c:156:21: warning: ‘psock’ may be used uninitialized in this function [-Wmaybe-uninitialized]
struct smap_psock *psock;
Fixes: 174a79ff95 ("bpf: sockmap with sk redirect support")
Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
In the devmap alloc map logic we check to ensure that the sizeof the
values are not greater than KMALLOC_MAX_SIZE. But, in the dev map case
we ensure the value size is 4bytes earlier in the function because all
values should be netdev ifindex values.
The second check is harmless but is not needed so remove it.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Recently we added a new map type called dev map used to forward XDP
packets between ports (6093ec2dc3). This patches introduces a
similar notion for sockets.
A sockmap allows users to add participating sockets to a map. When
sockets are added to the map enough context is stored with the
map entry to use the entry with a new helper
bpf_sk_redirect_map(map, key, flags)
This helper (analogous to bpf_redirect_map in XDP) is given the map
and an entry in the map. When called from a sockmap program, discussed
below, the skb will be sent on the socket using skb_send_sock().
With the above we need a bpf program to call the helper from that will
then implement the send logic. The initial site implemented in this
series is the recv_sock hook. For this to work we implemented a map
attach command to add attributes to a map. In sockmap we add two
programs a parse program and a verdict program. The parse program
uses strparser to build messages and pass them to the verdict program.
The parse programs use the normal strparser semantics. The verdict
program is of type SK_SKB.
The verdict program returns a verdict SK_DROP, or SK_REDIRECT for
now. Additional actions may be added later. When SK_REDIRECT is
returned, expected when bpf program uses bpf_sk_redirect_map(), the
sockmap logic will consult per cpu variables set by the helper routine
and pull the sock entry out of the sock map. This pattern follows the
existing redirect logic in cls and xdp programs.
This gives the flow,
recv_sock -> str_parser (parse_prog) -> verdict_prog -> skb_send_sock
\
-> kfree_skb
As an example use case a message based load balancer may use specific
logic in the verdict program to select the sock to send on.
Sample programs are provided in future patches that hopefully illustrate
the user interfaces. Also selftests are in follow-on patches.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
bpf_prog_inc_not_zero will be used by upcoming sockmap patches this
patch simply exports it so we can pull it in.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
State of a register doesn't matter if it wasn't read in reaching an exit;
a write screens off all reads downstream of it from all explored_states
upstream of it.
This allows us to prune many more branches; here are some processed insn
counts for some Cilium programs:
Program before after
bpf_lb_opt_-DLB_L3.o 6515 3361
bpf_lb_opt_-DLB_L4.o 8976 5176
bpf_lb_opt_-DUNKNOWN.o 2960 1137
bpf_lxc_opt_-DDROP_ALL.o 95412 48537
bpf_lxc_opt_-DUNKNOWN.o 141706 78718
bpf_netdev.o 24251 17995
bpf_overlay.o 10999 9385
The runtime is also improved; here are 'time' results in ms:
Program before after
bpf_lb_opt_-DLB_L3.o 24 6
bpf_lb_opt_-DLB_L4.o 26 11
bpf_lb_opt_-DUNKNOWN.o 11 2
bpf_lxc_opt_-DDROP_ALL.o 1288 139
bpf_lxc_opt_-DUNKNOWN.o 1768 234
bpf_netdev.o 62 31
bpf_overlay.o 15 13
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Enable the newly added jump opcodes, main parts are in two
different areas, namely direct packet access and dynamic map
value access. For the direct packet access, we now allow for
the following two new patterns to match in order to trigger
markings with find_good_pkt_pointers():
Variant 1 (access ok when taking the branch):
0: (61) r2 = *(u32 *)(r1 +76)
1: (61) r3 = *(u32 *)(r1 +80)
2: (bf) r0 = r2
3: (07) r0 += 8
4: (ad) if r0 < r3 goto pc+2
R0=pkt(id=0,off=8,r=0) R1=ctx R2=pkt(id=0,off=0,r=0)
R3=pkt_end R10=fp
5: (b7) r0 = 0
6: (95) exit
from 4 to 7: R0=pkt(id=0,off=8,r=8) R1=ctx
R2=pkt(id=0,off=0,r=8) R3=pkt_end R10=fp
7: (71) r0 = *(u8 *)(r2 +0)
8: (05) goto pc-4
5: (b7) r0 = 0
6: (95) exit
processed 11 insns, stack depth 0
Variant 2 (access ok on fall-through):
0: (61) r2 = *(u32 *)(r1 +76)
1: (61) r3 = *(u32 *)(r1 +80)
2: (bf) r0 = r2
3: (07) r0 += 8
4: (bd) if r3 <= r0 goto pc+1
R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8)
R3=pkt_end R10=fp
5: (71) r0 = *(u8 *)(r2 +0)
6: (b7) r0 = 1
7: (95) exit
from 4 to 6: R0=pkt(id=0,off=8,r=0) R1=ctx
R2=pkt(id=0,off=0,r=0) R3=pkt_end R10=fp
6: (b7) r0 = 1
7: (95) exit
processed 10 insns, stack depth 0
The above two basically just swap the branches where we need
to handle an exception and allow packet access compared to the
two already existing variants for find_good_pkt_pointers().
For the dynamic map value access, we add the new instructions
to reg_set_min_max() and reg_set_min_max_inv() in order to
learn bounds. Verifier test cases for both are added in a
follow-up patch.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, eBPF only understands BPF_JGT (>), BPF_JGE (>=),
BPF_JSGT (s>), BPF_JSGE (s>=) instructions, this means that
particularly *JLT/*JLE counterparts involving immediates need
to be rewritten from e.g. X < [IMM] by swapping arguments into
[IMM] > X, meaning the immediate first is required to be loaded
into a register Y := [IMM], such that then we can compare with
Y > X. Note that the destination operand is always required to
be a register.
This has the downside of having unnecessarily increased register
pressure, meaning complex program would need to spill other
registers temporarily to stack in order to obtain an unused
register for the [IMM]. Loading to registers will thus also
affect state pruning since we need to account for that register
use and potentially those registers that had to be spilled/filled
again. As a consequence slightly more stack space might have
been used due to spilling, and BPF programs are a bit longer
due to extra code involving the register load and potentially
required spill/fills.
Thus, add BPF_JLT (<), BPF_JLE (<=), BPF_JSLT (s<), BPF_JSLE (s<=)
counterparts to the eBPF instruction set. Modifying LLVM to
remove the NegateCC() workaround in a PoC patch at [1] and
allowing it to also emit the new instructions resulted in
cilium's BPF programs that are injected into the fast-path to
have a reduced program length in the range of 2-3% (e.g.
accumulated main and tail call sections from one of the object
file reduced from 4864 to 4729 insns), reduced complexity in
the range of 10-30% (e.g. accumulated sections reduced in one
of the cases from 116432 to 88428 insns), and reduced stack
usage in the range of 1-5% (e.g. accumulated sections from one
of the object files reduced from 824 to 784b).
The modification for LLVM will be incorporated in a backwards
compatible way. Plan is for LLVM to have i) a target specific
option to offer a possibility to explicitly enable the extension
by the user (as we have with -m target specific extensions today
for various CPU insns), and ii) have the kernel checked for
presence of the extensions and enable them transparently when
the user is selecting more aggressive options such as -march=native
in a bpf target context. (Other frontends generating BPF byte
code, e.g. ply can probe the kernel directly for its code
generation.)
[1] https://github.com/borkmann/llvm/tree/bpf-insns
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The function check_uarg_tail_zero() was created from bpf(2) for
BPF_OBJ_GET_INFO_BY_FD without taking the access_ok() nor the PAGE_SIZE
checks. Make this checks more generally available while unlikely to be
triggered, extend the memory range check and add an explanation
including why the ToCToU should not be a security concern.
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Link: https://lkml.kernel.org/r/CAGXu5j+vRGFvJZmjtAcT8Hi8B+Wz0e1b6VKYZHfQP_=DXzC4CQ@mail.gmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
The function check_uarg_tail_zero() may be useful for other part of the
code in the syscall.c file. Move this function at the beginning of the
file.
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The more detailed value tracking can reduce the effectiveness of pruning
for some programs. So, to avoid rejecting previously valid programs, up
the limit to 128kinsns. Hopefully we will be able to bring this back
down later by improving pruning performance.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allows us to, sometimes, combine information from a signed check of one
bound and an unsigned check of the other.
We now track the full range of possible values, rather than restricting
ourselves to [0, 1<<30) and considering anything beyond that as
unknown. While this is probably not necessary, it makes the code more
straightforward and symmetrical between signed and unsigned bounds.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unifies adjusted and unadjusted register value types (e.g. FRAME_POINTER is
now just a PTR_TO_STACK with zero offset).
Tracks value alignment by means of tracking known & unknown bits. This
also replaces the 'reg->imm' (leading zero bits) calculations for (what
were) UNKNOWN_VALUEs.
If pointer leaks are allowed, and adjust_ptr_min_max_vals returns -EACCES,
treat the pointer as an unknown scalar and try again, because we might be
able to conclude something about the result (e.g. pointer & 0x40 is either
0 or 0x40).
Verifier hooks in the netronome/nfp driver were changed to match the new
data structures.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Originally we used a mutex to protect concurrent devmap update
and delete operations from racing with netdev unregister notifier
callbacks.
The notifier hook is needed because we increment the netdev ref
count when a dev is added to the devmap. This ensures the netdev
reference is valid in the datapath. However, we don't want to block
unregister events, hence the initial mutex and notifier handler.
The concern was in the notifier hook we search the map for dev
entries that hold a refcnt on the net device being torn down. But,
in order to do this we require two steps,
(i) dereference the netdev: dev = rcu_dereference(map[i])
(ii) test ifindex: dev->ifindex == removing_ifindex
and then finally we can swap in the NULL dev in the map via an
xchg operation,
xchg(map[i], NULL)
The danger here is a concurrent update could run a different
xchg op concurrently leading us to replace the new dev with a
NULL dev incorrectly.
CPU 1 CPU 2
notifier hook bpf devmap update
dev = rcu_dereference(map[i])
dev = rcu_dereference(map[i])
xchg(map[i]), new_dev);
rcu_call(dev,...)
xchg(map[i], NULL)
The above flow would create the incorrect state with the dev
reference in the update path being lost. To resolve this the
original code used a mutex around the above block. However,
updates, deletes, and lookups occur inside rcu critical sections
so we can't use a mutex in this context safely.
Fortunately, by writing slightly better code we can avoid the
mutex altogether. If CPU 1 in the above example uses a cmpxchg
and _only_ replaces the dev reference in the map when it is in
fact the expected dev the race is removed completely. The two
cases being illustrated here, first the race condition,
CPU 1 CPU 2
notifier hook bpf devmap update
dev = rcu_dereference(map[i])
dev = rcu_dereference(map[i])
xchg(map[i]), new_dev);
rcu_call(dev,...)
odev = cmpxchg(map[i], dev, NULL)
Now we can test the cmpxchg return value, detect odev != dev and
abort. Or in the good case,
CPU 1 CPU 2
notifier hook bpf devmap update
dev = rcu_dereference(map[i])
odev = cmpxchg(map[i], dev, NULL)
[...]
Now 'odev == dev' and we can do proper cleanup.
And viola the original race we tried to solve with a mutex is
corrected and the trace noted by Sasha below is resolved due
to removal of the mutex.
Note: When walking the devmap and removing dev references as needed
we depend on the core to fail any calls to dev_get_by_index() using
the ifindex of the device being removed. This way we do not race with
the user while searching the devmap.
Additionally, the mutex was also protecting list add/del/read on
the list of maps in-use. This patch converts this to an RCU list
and spinlock implementation. This protects the list from concurrent
alloc/free operations. The notifier hook walks this list so it uses
RCU read semantics.
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747
in_atomic(): 1, irqs_disabled(): 0, pid: 16315, name: syz-executor1
1 lock held by syz-executor1/16315:
#0: (rcu_read_lock){......}, at: [<ffffffff8c363bc2>] map_delete_elem kernel/bpf/syscall.c:577 [inline]
#0: (rcu_read_lock){......}, at: [<ffffffff8c363bc2>] SYSC_bpf kernel/bpf/syscall.c:1427 [inline]
#0: (rcu_read_lock){......}, at: [<ffffffff8c363bc2>] SyS_bpf+0x1d32/0x4ba0 kernel/bpf/syscall.c:1388
Fixes: 2ddf71e23c ("net: add notifier hooks for devmap bpf map")
Reported-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Two minor conflicts in virtio_net driver (bug fix overlapping addition
of a helper) and MAINTAINERS (new driver edit overlapping revamp of
PHY entry).
Signed-off-by: David S. Miller <davem@davemloft.net>
bpf_prog_size(prog->len) is not the correct length we want to dump
back to user space. The code in bpf_prog_get_info_by_fd() uses this
to copy prog->insnsi to user space, but bpf_prog_size(prog->len) also
includes the size of struct bpf_prog itself plus program instructions
and is usually used either in context of accounting or for bpf_prog_alloc()
et al, thus we copy out of bounds in bpf_prog_get_info_by_fd()
potentially. Use the correct bpf_prog_insn_size() instead.
Fixes: 1e27097690 ("bpf: Add BPF_OBJ_GET_INFO_BY_FD")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
err in bpf_prog_get_info_by_fd() still holds 0 at that time from prior
check_uarg_tail_zero() check. Explicitly return -EFAULT instead, so
user space can be notified of buggy behavior.
Fixes: 1e27097690 ("bpf: Add BPF_OBJ_GET_INFO_BY_FD")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We forgot to set the error code on two error paths which means that we
return ERR_PTR(0) which is NULL. The caller, find_and_alloc_map(), is
not expecting that and will have a NULL dereference.
Fixes: 546ac1ffb7 ("bpf: add devmap, a map for storing net device references")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We have to subtract the src max from the dst min, and vice-versa, since
(e.g.) the smallest result comes from the largest subtrahend.
Fixes: 484611357c ("bpf: allow access into map value arrays")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from David Miller:
1) BPF verifier signed/unsigned value tracking fix, from Daniel
Borkmann, Edward Cree, and Josef Bacik.
2) Fix memory allocation length when setting up calls to
->ndo_set_mac_address, from Cong Wang.
3) Add a new cxgb4 device ID, from Ganesh Goudar.
4) Fix FIB refcount handling, we have to set it's initial value before
the configure callback (which can bump it). From David Ahern.
5) Fix double-free in qcom/emac driver, from Timur Tabi.
6) A bunch of gcc-7 string format overflow warning fixes from Arnd
Bergmann.
7) Fix link level headroom tests in ip_do_fragment(), from Vasily
Averin.
8) Fix chunk walking in SCTP when iterating over error and parameter
headers. From Alexander Potapenko.
9) TCP BBR congestion control fixes from Neal Cardwell.
10) Fix SKB fragment handling in bcmgenet driver, from Doug Berger.
11) BPF_CGROUP_RUN_PROG_SOCK_OPS needs to check for null __sk, from Cong
Wang.
12) xmit_recursion in ppp driver needs to be per-device not per-cpu,
from Gao Feng.
13) Cannot release skb->dst in UDP if IP options processing needs it.
From Paolo Abeni.
14) Some netdev ioctl ifr_name[] NULL termination fixes. From Alexander
Levin and myself.
15) Revert some rtnetlink notification changes that are causing
regressions, from David Ahern.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (83 commits)
net: bonding: Fix transmit load balancing in balance-alb mode
rds: Make sure updates to cp_send_gen can be observed
net: ethernet: ti: cpsw: Push the request_irq function to the end of probe
ipv4: initialize fib_trie prior to register_netdev_notifier call.
rtnetlink: allocate more memory for dev_set_mac_address()
net: dsa: b53: Add missing ARL entries for BCM53125
bpf: more tests for mixed signed and unsigned bounds checks
bpf: add test for mixed signed and unsigned bounds checks
bpf: fix up test cases with mixed signed/unsigned bounds
bpf: allow to specify log level and reduce it for test_verifier
bpf: fix mixed signed/unsigned derived min/max value bounds
ipv6: avoid overflow of offset in ip6_find_1stfragopt
net: tehuti: don't process data if it has not been copied from userspace
Revert "rtnetlink: Do not generate notifications for CHANGEADDR event"
net: dsa: mv88e6xxx: Enable CMODE config support for 6390X
dt-binding: ptp: Add SoC compatibility strings for dte ptp clock
NET: dwmac: Make dwmac reset unconditional
net: Zero terminate ifr_name in dev_ifname().
wireless: wext: terminate ifr name coming from userspace
netfilter: fix netfilter_net_init() return
...
Edward reported that there's an issue in min/max value bounds
tracking when signed and unsigned compares both provide hints
on limits when having unknown variables. E.g. a program such
as the following should have been rejected:
0: (7a) *(u64 *)(r10 -8) = 0
1: (bf) r2 = r10
2: (07) r2 += -8
3: (18) r1 = 0xffff8a94cda93400
5: (85) call bpf_map_lookup_elem#1
6: (15) if r0 == 0x0 goto pc+7
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp
7: (7a) *(u64 *)(r10 -16) = -8
8: (79) r1 = *(u64 *)(r10 -16)
9: (b7) r2 = -1
10: (2d) if r1 > r2 goto pc+3
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=0
R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp
11: (65) if r1 s> 0x1 goto pc+2
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=0,max_value=1
R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp
12: (0f) r0 += r1
13: (72) *(u8 *)(r0 +0) = 0
R0=map_value_adj(ks=8,vs=8,id=0),min_value=0,max_value=1 R1=inv,min_value=0,max_value=1
R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp
14: (b7) r0 = 0
15: (95) exit
What happens is that in the first part ...
8: (79) r1 = *(u64 *)(r10 -16)
9: (b7) r2 = -1
10: (2d) if r1 > r2 goto pc+3
... r1 carries an unsigned value, and is compared as unsigned
against a register carrying an immediate. Verifier deduces in
reg_set_min_max() that since the compare is unsigned and operation
is greater than (>), that in the fall-through/false case, r1's
minimum bound must be 0 and maximum bound must be r2. Latter is
larger than the bound and thus max value is reset back to being
'invalid' aka BPF_REGISTER_MAX_RANGE. Thus, r1 state is now
'R1=inv,min_value=0'. The subsequent test ...
11: (65) if r1 s> 0x1 goto pc+2
... is a signed compare of r1 with immediate value 1. Here,
verifier deduces in reg_set_min_max() that since the compare
is signed this time and operation is greater than (>), that
in the fall-through/false case, we can deduce that r1's maximum
bound must be 1, meaning with prior test, we result in r1 having
the following state: R1=inv,min_value=0,max_value=1. Given that
the actual value this holds is -8, the bounds are wrongly deduced.
When this is being added to r0 which holds the map_value(_adj)
type, then subsequent store access in above case will go through
check_mem_access() which invokes check_map_access_adj(), that
will then probe whether the map memory is in bounds based
on the min_value and max_value as well as access size since
the actual unknown value is min_value <= x <= max_value; commit
fce366a9dd ("bpf, verifier: fix alu ops against map_value{,
_adj} register types") provides some more explanation on the
semantics.
It's worth to note in this context that in the current code,
min_value and max_value tracking are used for two things, i)
dynamic map value access via check_map_access_adj() and since
commit 06c1c04972 ("bpf: allow helpers access to variable memory")
ii) also enforced at check_helper_mem_access() when passing a
memory address (pointer to packet, map value, stack) and length
pair to a helper and the length in this case is an unknown value
defining an access range through min_value/max_value in that
case. The min_value/max_value tracking is /not/ used in the
direct packet access case to track ranges. However, the issue
also affects case ii), for example, the following crafted program
based on the same principle must be rejected as well:
0: (b7) r2 = 0
1: (bf) r3 = r10
2: (07) r3 += -512
3: (7a) *(u64 *)(r10 -16) = -8
4: (79) r4 = *(u64 *)(r10 -16)
5: (b7) r6 = -1
6: (2d) if r4 > r6 goto pc+5
R1=ctx R2=imm0,min_value=0,max_value=0,min_align=2147483648 R3=fp-512
R4=inv,min_value=0 R6=imm-1,max_value=18446744073709551615,min_align=1 R10=fp
7: (65) if r4 s> 0x1 goto pc+4
R1=ctx R2=imm0,min_value=0,max_value=0,min_align=2147483648 R3=fp-512
R4=inv,min_value=0,max_value=1 R6=imm-1,max_value=18446744073709551615,min_align=1
R10=fp
8: (07) r4 += 1
9: (b7) r5 = 0
10: (6a) *(u16 *)(r10 -512) = 0
11: (85) call bpf_skb_load_bytes#26
12: (b7) r0 = 0
13: (95) exit
Meaning, while we initialize the max_value stack slot that the
verifier thinks we access in the [1,2] range, in reality we
pass -7 as length which is interpreted as u32 in the helper.
Thus, this issue is relevant also for the case of helper ranges.
Resetting both bounds in check_reg_overflow() in case only one
of them exceeds limits is also not enough as similar test can be
created that uses values which are within range, thus also here
learned min value in r1 is incorrect when mixed with later signed
test to create a range:
0: (7a) *(u64 *)(r10 -8) = 0
1: (bf) r2 = r10
2: (07) r2 += -8
3: (18) r1 = 0xffff880ad081fa00
5: (85) call bpf_map_lookup_elem#1
6: (15) if r0 == 0x0 goto pc+7
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp
7: (7a) *(u64 *)(r10 -16) = -8
8: (79) r1 = *(u64 *)(r10 -16)
9: (b7) r2 = 2
10: (3d) if r2 >= r1 goto pc+3
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3
R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp
11: (65) if r1 s> 0x4 goto pc+2
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0
R1=inv,min_value=3,max_value=4 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp
12: (0f) r0 += r1
13: (72) *(u8 *)(r0 +0) = 0
R0=map_value_adj(ks=8,vs=8,id=0),min_value=3,max_value=4
R1=inv,min_value=3,max_value=4 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp
14: (b7) r0 = 0
15: (95) exit
This leaves us with two options for fixing this: i) to invalidate
all prior learned information once we switch signed context, ii)
to track min/max signed and unsigned boundaries separately as
done in [0]. (Given latter introduces major changes throughout
the whole verifier, it's rather net-next material, thus this
patch follows option i), meaning we can derive bounds either
from only signed tests or only unsigned tests.) There is still the
case of adjust_reg_min_max_vals(), where we adjust bounds on ALU
operations, meaning programs like the following where boundaries
on the reg get mixed in context later on when bounds are merged
on the dst reg must get rejected, too:
0: (7a) *(u64 *)(r10 -8) = 0
1: (bf) r2 = r10
2: (07) r2 += -8
3: (18) r1 = 0xffff89b2bf87ce00
5: (85) call bpf_map_lookup_elem#1
6: (15) if r0 == 0x0 goto pc+6
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp
7: (7a) *(u64 *)(r10 -16) = -8
8: (79) r1 = *(u64 *)(r10 -16)
9: (b7) r2 = 2
10: (3d) if r2 >= r1 goto pc+2
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3
R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp
11: (b7) r7 = 1
12: (65) if r7 s> 0x0 goto pc+2
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3
R2=imm2,min_value=2,max_value=2,min_align=2 R7=imm1,max_value=0 R10=fp
13: (b7) r0 = 0
14: (95) exit
from 12 to 15: R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0
R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=imm1,min_value=1 R10=fp
15: (0f) r7 += r1
16: (65) if r7 s> 0x4 goto pc+2
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3
R2=imm2,min_value=2,max_value=2,min_align=2 R7=inv,min_value=4,max_value=4 R10=fp
17: (0f) r0 += r7
18: (72) *(u8 *)(r0 +0) = 0
R0=map_value_adj(ks=8,vs=8,id=0),min_value=4,max_value=4 R1=inv,min_value=3
R2=imm2,min_value=2,max_value=2,min_align=2 R7=inv,min_value=4,max_value=4 R10=fp
19: (b7) r0 = 0
20: (95) exit
Meaning, in adjust_reg_min_max_vals() we must also reset range
values on the dst when src/dst registers have mixed signed/
unsigned derived min/max value bounds with one unbounded value
as otherwise they can be added together deducing false boundaries.
Once both boundaries are established from either ALU ops or
compare operations w/o mixing signed/unsigned insns, then they
can safely be added to other regs also having both boundaries
established. Adding regs with one unbounded side to a map value
where the bounded side has been learned w/o mixing ops is
possible, but the resulting map value won't recover from that,
meaning such op is considered invalid on the time of actual
access. Invalid bounds are set on the dst reg in case i) src reg,
or ii) in case dst reg already had them. The only way to recover
would be to perform i) ALU ops but only 'add' is allowed on map
value types or ii) comparisons, but these are disallowed on
pointers in case they span a range. This is fine as only BPF_JEQ
and BPF_JNE may be performed on PTR_TO_MAP_VALUE_OR_NULL registers
which potentially turn them into PTR_TO_MAP_VALUE type depending
on the branch, so only here min/max value cannot be invalidated
for them.
In terms of state pruning, value_from_signed is considered
as well in states_equal() when dealing with adjusted map values.
With regards to breaking existing programs, there is a small
risk, but use-cases are rather quite narrow where this could
occur and mixing compares probably unlikely.
Joint work with Josef and Edward.
[0] https://lists.iovisor.org/pipermail/iovisor-dev/2017-June/000822.html
Fixes: 484611357c ("bpf: allow access into map value arrays")
Reported-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The BPF map devmap holds a refcnt on the net_device structure when
it is in the map. We need to do this to ensure on driver unload we
don't lose a dev reference.
However, its not very convenient to have to manually unload the map
when destroying a net device so add notifier handlers to do the cleanup
automatically. But this creates a race between update/destroy BPF
syscall and programs and the unregister netdev hook.
Unfortunately, the best I could come up with is either to live with
requiring manual removal of net devices from the map before removing
the net device OR to add a mutex in devmap to ensure the map is not
modified while we are removing a device. The fallout also requires
that BPF programs no longer update/delete the map from the BPF program
side because the mutex may sleep and this can not be done from inside
an rcu critical section. This is not a real problem though because I
have not come up with any use cases where this is actually useful in
practice. If/when we come up with a compelling user for this we may
need to revisit this.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For performance reasons we want to avoid updating the tail pointer in
the driver tx ring as much as possible. To accomplish this we add
batching support to the redirect path in XDP.
This adds another ndo op "xdp_flush" that is used to inform the driver
that it should bump the tail pointer on the TX ring.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
BPF programs can use the devmap with a bpf_redirect_map() helper
routine to forward packets to netdevice in map.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Device map (devmap) is a BPF map, primarily useful for networking
applications, that uses a key to lookup a reference to a netdevice.
The map provides a clean way for BPF programs to build virtual port
to physical port maps. Additionally, it provides a scoping function
for the redirect action itself allowing multiple optimizations. Future
patches will leverage the map to provide batching at the XDP layer.
Another optimization/feature, that is not yet implemented, would be
to support multiple netdevices per key to support efficient multicast
and broadcast support.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull ->s_options removal from Al Viro:
"Preparations for fsmount/fsopen stuff (coming next cycle). Everything
gets moved to explicit ->show_options(), killing ->s_options off +
some cosmetic bits around fs/namespace.c and friends. Basically, the
stuff needed to work with fsmount series with minimum of conflicts
with other work.
It's not strictly required for this merge window, but it would reduce
the PITA during the coming cycle, so it would be nice to have those
bits and pieces out of the way"
* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
isofs: Fix isofs_show_options()
VFS: Kill off s_options and helpers
orangefs: Implement show_options
9p: Implement show_options
isofs: Implement show_options
afs: Implement show_options
affs: Implement show_options
befs: Implement show_options
spufs: Implement show_options
bpf: Implement show_options
ramfs: Implement show_options
pstore: Implement show_options
omfs: Implement show_options
hugetlbfs: Implement show_options
VFS: Don't use save/replace_mount_options if not using generic_show_options
VFS: Provide empty name qstr
VFS: Make get_filesystem() return the affected filesystem
VFS: Clean up whitespace in fs/namespace.c and fs/super.c
Provide a function to create a NUL-terminated string from unterminated data
Implement the show_options superblock op for bpf as part of a bid to get
rid of s_options and generic_show_options() to make it easier to implement
a context-based mount where the mount options can be passed individually
over a file descriptor.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Alexei Starovoitov <ast@kernel.org>
cc: Daniel Borkmann <daniel@iogearbox.net>
cc: netdev@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently the verifier does not track imm across alu operations when
the source register is of unknown type. This adds additional pattern
matching to catch this and track imm. We've seen LLVM generating this
pattern while working on cilium.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
We do export through fdinfo already whether a prog is JITed or not,
given a program load can fail in case of either prog or tail call map
has JITed property, but neither both are JITed or not JITed, we can
facilitate error reporting in loaders like iproute2 through exporting
owner_jited of tail call map. We already do export owner_prog_type
through this facility, so parser can pick up both for comparison.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This work tries to make the semantics and code around the
narrower ctx access a bit easier to follow. Right now
everything is done inside the .is_valid_access(). Offset
matching is done differently for read/write types, meaning
writes don't support narrower access and thus matching only
on offsetof(struct foo, bar) is enough whereas for read
case that supports narrower access we must check for
offsetof(struct foo, bar) + offsetof(struct foo, bar) +
sizeof(<bar>) - 1 for each of the cases. For read cases of
individual members that don't support narrower access (like
packet pointers or skb->cb[] case which has its own narrow
access logic), we check as usual only offsetof(struct foo,
bar) like in write case. Then, for the case where narrower
access is allowed, we also need to set the aux info for the
access. Meaning, ctx_field_size and converted_op_size have
to be set. First is the original field size e.g. sizeof(<bar>)
as in above example from the user facing ctx, and latter
one is the target size after actual rewrite happened, thus
for the kernel facing ctx. Also here we need the range match
and we need to keep track changing convert_ctx_access() and
converted_op_size from is_valid_access() as both are not at
the same location.
We can simplify the code a bit: check_ctx_access() becomes
simpler in that we only store ctx_field_size as a meta data
and later in convert_ctx_accesses() we fetch the target_size
right from the location where we do convert. Should the verifier
be misconfigured we do reject for BPF_WRITE cases or target_size
that are not provided. For the subsystems, we always work on
ranges in is_valid_access() and add small helpers for ranges
and narrow access, convert_ctx_accesses() sets target_size
for the relevant instruction.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Cc: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Created a new BPF program type, BPF_PROG_TYPE_SOCK_OPS, and a corresponding
struct that allows BPF programs of this type to access some of the
socket's fields (such as IP addresses, ports, etc.). It uses the
existing bpf cgroups infrastructure so the programs can be attached per
cgroup with full inheritance support. The program will be called at
appropriate times to set relevant connections parameters such as buffer
sizes, SYN and SYN-ACK RTOs, etc., based on connection information such
as IP addresses, port numbers, etc.
Alghough there are already 3 mechanisms to set parameters (sysctls,
route metrics and setsockopts), this new mechanism provides some
distinct advantages. Unlike sysctls, it can set parameters per
connection. In contrast to route metrics, it can also use port numbers
and information provided by a user level program. In addition, it could
set parameters probabilistically for evaluation purposes (i.e. do
something different on 10% of the flows and compare results with the
other 90% of the flows). Also, in cases where IPv6 addresses contain
geographic information, the rules to make changes based on the distance
(or RTT) between the hosts are much easier than route metric rules and
can be global. Finally, unlike setsockopt, it oes not require
application changes and it can be updated easily at any time.
Although the bpf cgroup framework already contains a sock related
program type (BPF_PROG_TYPE_CGROUP_SOCK), I created the new type
(BPF_PROG_TYPE_SOCK_OPS) beccause the existing type expects to be called
only once during the connections's lifetime. In contrast, the new
program type will be called multiple times from different places in the
network stack code. For example, before sending SYN and SYN-ACKs to set
an appropriate timeout, when the connection is established to set
congestion control, etc. As a result it has "op" field to specify the
type of operation requested.
The purpose of this new program type is to simplify setting connection
parameters, such as buffer sizes, TCP's SYN RTO, etc. For example, it is
easy to use facebook's internal IPv6 addresses to determine if both hosts
of a connection are in the same datacenter. Therefore, it is easy to
write a BPF program to choose a small SYN RTO value when both hosts are
in the same datacenter.
This patch only contains the framework to support the new BPF program
type, following patches add the functionality to set various connection
parameters.
This patch defines a new BPF program type: BPF_PROG_TYPE_SOCKET_OPS
and a new bpf syscall command to load a new program of this type:
BPF_PROG_LOAD_SOCKET_OPS.
Two new corresponding structs (one for the kernel one for the user/BPF
program):
/* kernel version */
struct bpf_sock_ops_kern {
struct sock *sk;
__u32 op;
union {
__u32 reply;
__u32 replylong[4];
};
};
/* user version
* Some fields are in network byte order reflecting the sock struct
* Use the bpf_ntohl helper macro in samples/bpf/bpf_endian.h to
* convert them to host byte order.
*/
struct bpf_sock_ops {
__u32 op;
union {
__u32 reply;
__u32 replylong[4];
};
__u32 family;
__u32 remote_ip4; /* In network byte order */
__u32 local_ip4; /* In network byte order */
__u32 remote_ip6[4]; /* In network byte order */
__u32 local_ip6[4]; /* In network byte order */
__u32 remote_port; /* In network byte order */
__u32 local_port; /* In host byte horder */
};
Currently there are two types of ops. The first type expects the BPF
program to return a value which is then used by the caller (or a
negative value to indicate the operation is not supported). The second
type expects state changes to be done by the BPF program, for example
through a setsockopt BPF helper function, and they ignore the return
value.
The reply fields of the bpf_sockt_ops struct are there in case a bpf
program needs to return a value larger than an integer.
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Leaking kernel addresses on unpriviledged is generally disallowed,
for example, verifier rejects the following:
0: (b7) r0 = 0
1: (18) r2 = 0xffff897e82304400
3: (7b) *(u64 *)(r1 +48) = r2
R2 leaks addr into ctx
Doing pointer arithmetic on them is also forbidden, so that they
don't turn into unknown value and then get leaked out. However,
there's xadd as a special case, where we don't check the src reg
for being a pointer register, e.g. the following will pass:
0: (b7) r0 = 0
1: (7b) *(u64 *)(r1 +48) = r0
2: (18) r2 = 0xffff897e82304400 ; map
4: (db) lock *(u64 *)(r1 +48) += r2
5: (95) exit
We could store the pointer into skb->cb, loose the type context,
and then read it out from there again to leak it eventually out
of a map value. Or more easily in a different variant, too:
0: (bf) r6 = r1
1: (7a) *(u64 *)(r10 -8) = 0
2: (bf) r2 = r10
3: (07) r2 += -8
4: (18) r1 = 0x0
6: (85) call bpf_map_lookup_elem#1
7: (15) if r0 == 0x0 goto pc+3
R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R6=ctx R10=fp
8: (b7) r3 = 0
9: (7b) *(u64 *)(r0 +0) = r3
10: (db) lock *(u64 *)(r0 +0) += r6
11: (b7) r0 = 0
12: (95) exit
from 7 to 11: R0=inv,min_value=0,max_value=0 R6=ctx R10=fp
11: (b7) r0 = 0
12: (95) exit
Prevent this by checking xadd src reg for pointer types. Also
add a couple of test cases related to this.
Fixes: 1be7f75d16 ("bpf: enable non-root eBPF programs")
Fixes: 17a5267067 ("bpf: verifier (add verifier core)")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The index is off-by-one when fp->aux->stack_depth
has already been rounded up to 32. In particular,
if stack_depth is 512, the index will be 16.
The fix is to round_up and then takes -1 instead of round_down.
[ 22.318680] ==================================================================
[ 22.319745] BUG: KASAN: global-out-of-bounds in bpf_prog_select_runtime+0x48a/0x670
[ 22.320737] Read of size 8 at addr ffffffff82aadae0 by task sockex3/1946
[ 22.321646]
[ 22.321858] CPU: 1 PID: 1946 Comm: sockex3 Tainted: G W 4.12.0-rc6-01680-g2ee87db3a287 #22
[ 22.323061] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.el7.centos 04/01/2014
[ 22.324260] Call Trace:
[ 22.324612] dump_stack+0x67/0x99
[ 22.325081] print_address_description+0x1e8/0x290
[ 22.325734] ? bpf_prog_select_runtime+0x48a/0x670
[ 22.326360] kasan_report+0x265/0x350
[ 22.326860] __asan_report_load8_noabort+0x19/0x20
[ 22.327484] bpf_prog_select_runtime+0x48a/0x670
[ 22.328109] bpf_prog_load+0x626/0xd40
[ 22.328637] ? __bpf_prog_charge+0xc0/0xc0
[ 22.329222] ? check_nnp_nosuid.isra.61+0x100/0x100
[ 22.329890] ? __might_fault+0xf6/0x1b0
[ 22.330446] ? lock_acquire+0x360/0x360
[ 22.331013] SyS_bpf+0x67c/0x24d0
[ 22.331491] ? trace_hardirqs_on+0xd/0x10
[ 22.332049] ? __getnstimeofday64+0xaf/0x1c0
[ 22.332635] ? bpf_prog_get+0x20/0x20
[ 22.333135] ? __audit_syscall_entry+0x300/0x600
[ 22.333770] ? syscall_trace_enter+0x540/0xdd0
[ 22.334339] ? exit_to_usermode_loop+0xe0/0xe0
[ 22.334950] ? do_syscall_64+0x48/0x410
[ 22.335446] ? bpf_prog_get+0x20/0x20
[ 22.335954] do_syscall_64+0x181/0x410
[ 22.336454] entry_SYSCALL64_slow_path+0x25/0x25
[ 22.337121] RIP: 0033:0x7f263fe81f19
[ 22.337618] RSP: 002b:00007ffd9a3440c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000141
[ 22.338619] RAX: ffffffffffffffda RBX: 0000000000aac5fb RCX: 00007f263fe81f19
[ 22.339600] RDX: 0000000000000030 RSI: 00007ffd9a3440d0 RDI: 0000000000000005
[ 22.340470] RBP: 0000000000a9a1e0 R08: 0000000000a9a1e0 R09: 0000009d00000001
[ 22.341430] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000010000
[ 22.342411] R13: 0000000000a9a023 R14: 0000000000000001 R15: 0000000000000003
[ 22.343369]
[ 22.343593] The buggy address belongs to the variable:
[ 22.344241] interpreters+0x80/0x980
[ 22.344708]
[ 22.344908] Memory state around the buggy address:
[ 22.345556] ffffffff82aad980: 00 00 00 04 fa fa fa fa 04 fa fa fa fa fa fa fa
[ 22.346449] ffffffff82aada00: 00 00 00 00 00 fa fa fa fa fa fa fa 00 00 00 00
[ 22.347361] >ffffffff82aada80: 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa fa
[ 22.348301] ^
[ 22.349142] ffffffff82aadb00: 00 01 fa fa fa fa fa fa 00 00 00 00 00 00 00 00
[ 22.350058] ffffffff82aadb80: 00 00 07 fa fa fa fa fa 00 00 05 fa fa fa fa fa
[ 22.350984] ==================================================================
Fixes: b870aa901f ("bpf: use different interpreter depending on required stack size")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch allows userspace to do BPF_MAP_LOOKUP_ELEM on
BPF_MAP_TYPE_PROG_ARRAY,
BPF_MAP_TYPE_ARRAY_OF_MAPS and
BPF_MAP_TYPE_HASH_OF_MAPS.
The lookup returns a prog-id or map-id to the userspace.
The userspace can then use the BPF_PROG_GET_FD_BY_ID
or BPF_MAP_GET_FD_BY_ID to get a fd.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 31fd85816d ("bpf: permits narrower load from bpf program
context fields") permits narrower load for certain ctx fields.
The commit however will already generate a masking even if
the prog-specific ctx conversion produces the result with
narrower size.
For example, for __sk_buff->protocol, the ctx conversion
loads the data into register with 2-byte load.
A narrower 2-byte load should not generate masking.
For __sk_buff->vlan_present, the conversion function
set the result as either 0 or 1, essentially a byte.
The narrower 2-byte or 1-byte load should not generate masking.
To avoid unnecessary masking, prog-specific *_is_valid_access
now passes converted_op_size back to verifier, which indicates
the valid data width after perceived future conversion.
Based on this information, verifier is able to avoid
unnecessary marking.
Since we want more information back from prog-specific
*_is_valid_access checking, all of them are packed into
one data structure for more clarity.
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, verifier will reject a program if it contains an
narrower load from the bpf context structure. For example,
__u8 h = __sk_buff->hash, or
__u16 p = __sk_buff->protocol
__u32 sample_period = bpf_perf_event_data->sample_period
which are narrower loads of 4-byte or 8-byte field.
This patch solves the issue by:
. Introduce a new parameter ctx_field_size to carry the
field size of narrower load from prog type
specific *__is_valid_access validator back to verifier.
. The non-zero ctx_field_size for a memory access indicates
(1). underlying prog type specific convert_ctx_accesses
supporting non-whole-field access
(2). the current insn is a narrower or whole field access.
. In verifier, for such loads where load memory size is
less than ctx_field_size, verifier transforms it
to a full field load followed by proper masking.
. Currently, __sk_buff and bpf_perf_event_data->sample_period
are supporting narrowing loads.
. Narrower stores are still not allowed as typical ctx stores
are just normal stores.
Because of this change, some tests in verifier will fail and
these tests are removed. As a bonus, rename some out of bound
__sk_buff->cb access to proper field name and remove two
redundant "skb cb oob" tests.
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Right now, we don't reset the id of spilled registers in case of
clear_all_pkt_pointers(). Given pkt_pointers are highly likely to
contain an id, do so by reusing __mark_reg_unknown_value().
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Whenever we set the register to the type CONST_IMM, we currently don't
reset the id to 0. id member is not used in CONST_IMM case, so don't
let it become stale, where pruning won't be able to match later on.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
spilled_regs[] state is only used for stack slots of type STACK_SPILL,
never for STACK_MISC. Right now, in states_equal(), even if we have
old and current stack state of type STACK_MISC, we compare spilled_regs[]
for that particular offset. Just skip these like we do everywhere else.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit fb9a307d11 ("bpf: Allow CGROUP_SKB eBPF program to
access sk_buff") enabled programs of BPF_PROG_TYPE_CGROUP_SKB
type to use ld_abs/ind instructions. However, at this point,
we cannot use them, since offsets relative to SKF_LL_OFF will
end up pointing skb_mac_header(skb) out of bounds since in the
egress path it is not yet set at that point in time, but only
after __dev_queue_xmit() did a general reset on the mac header.
bpf_internal_load_pointer_neg_helper() will then end up reading
data from a wrong offset.
BPF_PROG_TYPE_CGROUP_SKB programs can use bpf_skb_load_bytes()
already to access packet data, which is also more flexible than
the insns carried over from cBPF.
Fixes: fb9a307d11 ("bpf: Allow CGROUP_SKB eBPF program to access sk_buff")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Chenbo Feng <fengc@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A single BPF_OBJ_GET_INFO_BY_FD cmd is used to obtain the info
for both bpf_prog and bpf_map. The kernel can figure out the
fd is associated with a bpf_prog or bpf_map.
The suggested struct bpf_prog_info and struct bpf_map_info are
not meant to be a complete list and it is not the goal of this patch.
New fields can be added in the future patch.
The focus of this patch is to create the interface,
BPF_OBJ_GET_INFO_BY_FD cmd for exposing the bpf_prog's and
bpf_map's info.
The obj's info, which will be extended (and get bigger) over time, is
separated from the bpf_attr to avoid bloating the bpf_attr.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add BPF_MAP_GET_FD_BY_ID command to allow user to get a fd
from a bpf_map's ID.
bpf_map_inc_not_zero() is added and is called with map_idr_lock
held.
__bpf_map_put() is also added which has the 'bool do_idr_lock'
param to decide if the map_idr_lock should be acquired when
freeing the map->id.
In the error path of bpf_map_inc_not_zero(), it may have to
call __bpf_map_put(map, false) which does not need
to take the map_idr_lock when freeing the map->id.
It is currently limited to CAP_SYS_ADMIN which we can
consider to lift it in followup patches.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add BPF_PROG_GET_FD_BY_ID command to allow user to get a fd
from a bpf_prog's ID.
bpf_prog_inc_not_zero() is added and is called with prog_idr_lock
held.
__bpf_prog_put() is also added which has the 'bool do_idr_lock'
param to decide if the prog_idr_lock should be acquired when
freeing the prog->id.
In the error path of bpf_prog_inc_not_zero(), it may have to
call __bpf_prog_put(map, false) which does not need
to take the prog_idr_lock when freeing the prog->id.
It is currently limited to CAP_SYS_ADMIN which we can
consider to lift it in followup patches.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Daniel Borkmann