linux.git/tools/include/uapi/linux, branch v6.6.56

bpf: Replace bpf_lpm_trie_key 0-length array with flexible array

2024-08-19T04:04:27+00:00

[ Upstream commit 896880ff30866f386ebed14ab81ce1ad3710cfc4 ]

Replace deprecated 0-length array in struct bpf_lpm_trie_key with
flexible array. Found with GCC 13:

../kernel/bpf/lpm_trie.c:207:51: warning: array subscript i is outside array bounds of 'const __u8[0]' {aka 'const unsigned char[]'} [-Warray-bounds=]
  207 |                                        *(__be16 *)&key->data[i]);
      |                                                   ^~~~~~~~~~~~~
../include/uapi/linux/swab.h:102:54: note: in definition of macro '__swab16'
  102 | #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
      |                                                      ^
../include/linux/byteorder/generic.h:97:21: note: in expansion of macro '__be16_to_cpu'
   97 | #define be16_to_cpu __be16_to_cpu
      |                     ^~~~~~~~~~~~~
../kernel/bpf/lpm_trie.c:206:28: note: in expansion of macro 'be16_to_cpu'
  206 |                 u16 diff = be16_to_cpu(*(__be16 *)&node->data[i]
^
      |                            ^~~~~~~~~~~
In file included from ../include/linux/bpf.h:7:
../include/uapi/linux/bpf.h:82:17: note: while referencing 'data'
   82 |         __u8    data[0];        /* Arbitrary size */
      |                 ^~~~

And found at run-time under CONFIG_FORTIFY_SOURCE:

  UBSAN: array-index-out-of-bounds in kernel/bpf/lpm_trie.c:218:49
  index 0 is out of range for type '__u8 [*]'

Changing struct bpf_lpm_trie_key is difficult since has been used by
userspace. For example, in Cilium:

	struct egress_gw_policy_key {
	        struct bpf_lpm_trie_key lpm_key;
	        __u32 saddr;
	        __u32 daddr;
	};

While direct references to the "data" member haven't been found, there
are static initializers what include the final member. For example,
the "{}" here:

        struct egress_gw_policy_key in_key = {
                .lpm_key = { 32 + 24, {} },
                .saddr   = CLIENT_IP,
                .daddr   = EXTERNAL_SVC_IP & 0Xffffff,
        };

To avoid the build time and run time warnings seen with a 0-sized
trailing array for struct bpf_lpm_trie_key, introduce a new struct
that correctly uses a flexible array for the trailing bytes,
struct bpf_lpm_trie_key_u8. As part of this, include the "header"
portion (which is just the "prefixlen" member), so it can be used
by anything building a bpf_lpr_trie_key that has trailing members that
aren't a u8 flexible array (like the self-test[1]), which is named
struct bpf_lpm_trie_key_hdr.

Unfortunately, C++ refuses to parse the __struct_group() helper, so
it is not possible to define struct bpf_lpm_trie_key_hdr directly in
struct bpf_lpm_trie_key_u8, so we must open-code the union directly.

Adjust the kernel code to use struct bpf_lpm_trie_key_u8 through-out,
and for the selftest to use struct bpf_lpm_trie_key_hdr. Add a comment
to the UAPI header directing folks to the two new options.

Reported-by: Mark Rutland 
Signed-off-by: Kees Cook 
Signed-off-by: Daniel Borkmann 
Acked-by: Gustavo A. R. Silva 
Closes: https://paste.debian.net/hidden/ca500597/
Link: https://lore.kernel.org/all/202206281009.4332AA33@keescook/ [1]
Link: https://lore.kernel.org/bpf/20240222155612.it.533-kees@kernel.org
Stable-dep-of: 59f2f841179a ("bpf: Avoid kfree_rcu() under lock in bpf_lpm_trie.")
Signed-off-by: Sasha Levin

bpf: Pack struct bpf_fib_lookup

2024-06-12T09:11:38+00:00

[ Upstream commit f91717007217d975aa975ddabd91ae1a107b9bff ]

The struct bpf_fib_lookup is supposed to be of size 64. A recent commit
59b418c7063d ("bpf: Add a check for struct bpf_fib_lookup size") added
a static assertion to check this property so that future changes to the
structure will not accidentally break this assumption.

As it immediately turned out, on some 32-bit arm systems, when AEABI=n,
the total size of the structure was equal to 68, see [1]. This happened
because the bpf_fib_lookup structure contains a union of two 16-bit
fields:

    union {
            __u16 tot_len;
            __u16 mtu_result;
    };

which was supposed to compile to a 16-bit-aligned 16-bit field. On the
aforementioned setups it was instead both aligned and padded to 32-bits.

Declare this inner union as __attribute__((packed, aligned(2))) such
that it always is of size 2 and is aligned to 16 bits.

  [1] https://lore.kernel.org/all/CA+G9fYtsoP51f-oP_Sp5MOq-Ffv8La2RztNpwvE6+R1VtFiLrw@mail.gmail.com/#t

Reported-by: Naresh Kamboju 
Fixes: e1850ea9bd9e ("bpf: bpf_fib_lookup return MTU value as output when looked up")
Signed-off-by: Anton Protopopov 
Signed-off-by: Andrii Nakryiko 
Reviewed-by: Alexander Lobakin 
Acked-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20240403123303.1452184-1-aspsk@isovalent.com
Signed-off-by: Sasha Levin

bpf: Derive source IP addr via bpf_*_fib_lookup()

2024-03-01T12:35:04+00:00

commit dab4e1f06cabb6834de14264394ccab197007302 upstream.

Extend the bpf_fib_lookup() helper by making it to return the source
IPv4/IPv6 address if the BPF_FIB_LOOKUP_SRC flag is set.

For example, the following snippet can be used to derive the desired
source IP address:

    struct bpf_fib_lookup p = { .ipv4_dst = ip4->daddr };

    ret = bpf_skb_fib_lookup(skb, p, sizeof(p),
            BPF_FIB_LOOKUP_SRC | BPF_FIB_LOOKUP_SKIP_NEIGH);
    if (ret != BPF_FIB_LKUP_RET_SUCCESS)
        return TC_ACT_SHOT;

    /* the p.ipv4_src now contains the source address */

The inability to derive the proper source address may cause malfunctions
in BPF-based dataplanes for hosts containing netdevs with more than one
routable IP address or for multi-homed hosts.

For example, Cilium implements packet masquerading in BPF. If an
egressing netdev to which the Cilium's BPF prog is attached has
multiple IP addresses, then only one [hardcoded] IP address can be used for
masquerading. This breaks connectivity if any other IP address should have
been selected instead, for example, when a public and private addresses
are attached to the same egress interface.

The change was tested with Cilium [1].

Nikolay Aleksandrov helped to figure out the IPv6 addr selection.

[1]: https://github.com/cilium/cilium/pull/28283

Signed-off-by: Martynas Pumputis 
Link: https://lore.kernel.org/r/20231007081415.33502-2-m@lambda.lt
Signed-off-by: Martin KaFai Lau 
Cc: Daniel Borkmann 
Signed-off-by: Greg Kroah-Hartman

bpf: Add crosstask check to __bpf_get_stack

2024-01-25T23:35:19+00:00

[ Upstream commit b8e3a87a627b575896e448021e5c2f8a3bc19931 ]

Currently get_perf_callchain only supports user stack walking for
the current task. Passing the correct *crosstask* param will return
0 frames if the task passed to __bpf_get_stack isn't the current
one instead of a single incorrect frame/address. This change
passes the correct *crosstask* param but also does a preemptive
check in __bpf_get_stack if the task is current and returns
-EOPNOTSUPP if it is not.

This issue was found using bpf_get_task_stack inside a BPF
iterator ("iter/task"), which iterates over all tasks.
bpf_get_task_stack works fine for fetching kernel stacks
but because get_perf_callchain relies on the caller to know
if the requested *task* is the current one (via *crosstask*)
it was failing in a confusing way.

It might be possible to get user stacks for all tasks utilizing
something like access_process_vm but that requires the bpf
program calling bpf_get_task_stack to be sleepable and would
therefore be a breaking change.

Fixes: fa28dcb82a38 ("bpf: Introduce helper bpf_get_task_stack()")
Signed-off-by: Jordan Rome 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20231108112334.3433136-1-jordalgo@meta.com
Signed-off-by: Sasha Levin

mm: add a NO_INHERIT flag to the PR_SET_MDWE prctl

2023-12-03T06:33:06+00:00

[ Upstream commit 24e41bf8a6b424c76c5902fb999e9eca61bdf83d ]

This extends the current PR_SET_MDWE prctl arg with a bit to indicate that
the process doesn't want MDWE protection to propagate to children.

To implement this no-inherit mode, the tag in current->mm->flags must be
absent from MMF_INIT_MASK.  This means that the encoding for "MDWE but
without inherit" is different in the prctl than in the mm flags.  This
leads to a bit of bit-mangling in the prctl implementation.

Link: https://lkml.kernel.org/r/20230828150858.393570-6-revest@chromium.org
Signed-off-by: Florent Revest 
Reviewed-by: Kees Cook 
Reviewed-by: Catalin Marinas 
Cc: Alexey Izbyshev 
Cc: Anshuman Khandual 
Cc: Ayush Jain 
Cc: David Hildenbrand 
Cc: Greg Thelen 
Cc: Joey Gouly 
Cc: KP Singh 
Cc: Mark Brown 
Cc: Michal Hocko 
Cc: Peter Xu 
Cc: Ryan Roberts 
Cc: Szabolcs Nagy 
Cc: Topi Miettinen 
Signed-off-by: Andrew Morton 
Stable-dep-of: 793838138c15 ("prctl: Disable prctl(PR_SET_MDWE) on parisc")
Signed-off-by: Sasha Levin

mm: make PR_MDWE_REFUSE_EXEC_GAIN an unsigned long

2023-11-28T17:20:06+00:00

commit 0da668333fb07805c2836d5d50e26eda915b24a1 upstream.

Defining a prctl flag as an int is a footgun because on a 64 bit machine
and with a variadic implementation of prctl (like in musl and glibc), when
used directly as a prctl argument, it can get casted to long with garbage
upper bits which would result in unexpected behaviors.

This patch changes the constant to an unsigned long to eliminate that
possibilities.  This does not break UAPI.

I think that a stable backport would be "nice to have": to reduce the
chances that users build binaries that could end up with garbage bits in
their MDWE prctl arguments.  We are not aware of anyone having yet
encountered this corner case with MDWE prctls but a backport would reduce
the likelihood it happens, since this sort of issues has happened with
other prctls.  But If this is perceived as a backporting burden, I suppose
we could also live without a stable backport.

Link: https://lkml.kernel.org/r/20230828150858.393570-5-revest@chromium.org
Fixes: b507808ebce2 ("mm: implement memory-deny-write-execute as a prctl")
Signed-off-by: Florent Revest 
Suggested-by: Alexey Izbyshev 
Reviewed-by: David Hildenbrand 
Reviewed-by: Kees Cook 
Acked-by: Catalin Marinas 
Cc: Anshuman Khandual 
Cc: Ayush Jain 
Cc: Greg Thelen 
Cc: Joey Gouly 
Cc: KP Singh 
Cc: Mark Brown 
Cc: Michal Hocko 
Cc: Peter Xu 
Cc: Ryan Roberts 
Cc: Szabolcs Nagy 
Cc: Topi Miettinen 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'perf-tools-fixes-for-v6.6-1-2023-09-25' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

2023-09-26T15:41:26+00:00

Pull perf tools fixes from Namhyung Kim:
 "Build:

   - Update header files in the tools/**/include directory to sync with
     the kernel sources as usual.

   - Remove unused bpf-prologue files. While it's not strictly a fix,
     but the functionality was removed in this cycle so better to get
     rid of the code together.

   - Other minor build fixes.

  Misc:

   - Fix uninitialized memory access in PMU parsing code

   - Fix segfaults on software event"

* tag 'perf-tools-fixes-for-v6.6-1-2023-09-25' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools:
  perf jevent: fix core dump on software events on s390
  perf pmu: Ensure all alias variables are initialized
  perf jevents metric: Fix type of strcmp_cpuid_str
  perf trace: Avoid compile error wrt redefining bool
  perf bpf-prologue: Remove unused file
  tools headers UAPI: Update tools's copy of drm.h headers
  tools arch x86: Sync the msr-index.h copy with the kernel sources
  perf bench sched-seccomp-notify: Use the tools copy of seccomp.h UAPI
  tools headers UAPI: Copy seccomp.h to be able to build 'perf bench' in older systems
  tools headers UAPI: Sync files changed by new fchmodat2 and map_shadow_stack syscalls with the kernel sources
  perf tools: Update copy of libbpf's hashmap.c

tools headers UAPI: Copy seccomp.h to be able to build 'perf bench' in older systems

2023-09-13T11:48:48+00:00

The new 'perf bench' for sched-seccomp-notify uses defines and types not
available in older systems where we want to have perf available, so grab
a copy of this UAPI from the kernel sources to allow that.

This will be checked in the future for drift from the original when we
build the perf tool, that will warn when that happens like:

  make: Entering directory '/var/home/acme/git/perf-tools/tools/perf'
    BUILD:   Doing 'make -j32' parallel build
  Warning: Kernel ABI header differences:

Cc: Adrian Hunter 
Cc: Andrei Vagin 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Kees Kook 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/lkml/ZQGhMXtwX7RvV3ya@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

bpf: Clarify error expectations from bpf_clone_redirect

2023-09-11T20:29:19+00:00

Commit 151e887d8ff9 ("veth: Fixing transmit return status for dropped
packets") exposed the fact that bpf_clone_redirect is capable of
returning raw NET_XMIT_XXX return codes.

This is in the conflict with its UAPI doc which says the following:
"0 on success, or a negative error in case of failure."

Update the UAPI to reflect the fact that bpf_clone_redirect can
return positive error numbers, but don't explicitly define
their meaning.

Reported-by: Daniel Borkmann 
Signed-off-by: Stanislav Fomichev 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/20230911194731.286342-1-sdf@google.com

bpf: Add pid filter support for uprobe_multi link

2023-08-21T22:51:25+00:00

Adding support to specify pid for uprobe_multi link and the uprobes
are created only for task with given pid value.

Using the consumer.filter filter callback for that, so the task gets
filtered during the uprobe installation.

We still need to check the task during runtime in the uprobe handler,
because the handler could get executed if there's another system
wide consumer on the same uprobe (thanks Oleg for the insight).

Cc: Oleg Nesterov 
Reviewed-by: Oleg Nesterov 
Signed-off-by: Jiri Olsa 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/r/20230809083440.3209381-6-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov