linux-stable.git/kernel/bpf/btf.c, branch v4.19.321

bpf: btf: fix truncated last_member_type_id in btf_struct_resolve

2022-10-26T11:19:25+00:00

[ Upstream commit a37a32583e282d8d815e22add29bc1e91e19951a ]

When trying to finish resolving a struct member, btf_struct_resolve
saves the member type id in a u16 temporary variable. This truncates
the 32 bit type id value if it exceeds UINT16_MAX.

As a result, structs that have members with type ids > UINT16_MAX and
which need resolution will fail with a message like this:

    [67414] STRUCT ff_device size=120 vlen=12
        effect_owners type_id=67434 bits_offset=960 Member exceeds struct_size

Fix this by changing the type of last_member_type_id to u32.

Fixes: a0791f0df7d2 ("bpf: fix BTF limits")
Reviewed-by: Stanislav Fomichev 
Signed-off-by: Lorenz Bauer 
Link: https://lore.kernel.org/r/20220910110120.339242-1-oss@lmb.io
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

bpf: Explicitly memset some bpf info structures declared on the stack

2020-04-02T13:28:23+00:00

commit 5c6f25887963f15492b604dd25cb149c501bbabf upstream.

Trying to initialize a structure with "= {};" will not always clean out
all padding locations in a structure. So be explicit and call memset to
initialize everything for a number of bpf information structures that
are then copied from userspace, sometimes from smaller memory locations
than the size of the structure.

Reported-by: Daniel Borkmann 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Daniel Borkmann 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/bpf/20200320162258.GA794295@kroah.com
Signed-off-by: Greg Kroah-Hartman

bpf/btf: Fix BTF verification of enum members in struct/union

2020-04-02T13:28:19+00:00

commit da6c7faeb103c493e505e87643272f70be586635 upstream.

btf_enum_check_member() was currently sure to recognize the size of
"enum" type members in struct/union as the size of "int" even if
its size was packed.

This patch fixes BTF enum verification to use the correct size
of member in BPF programs.

Fixes: 179cde8cef7e ("bpf: btf: Check members of struct/union")
Signed-off-by: Yoshiki Komachi 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/1583825550-18606-2-git-send-email-komachi.yoshiki@gmail.com
Signed-off-by: Greg Kroah-Hartman

bpf: btf: check name validity for various types

2019-12-13T07:52:09+00:00

[ Upstream commit eb04bbb608e683f8fd3ef7f716e2fa32dd90861f ]

This patch added name checking for the following types:
 . BTF_KIND_PTR, BTF_KIND_ARRAY, BTF_KIND_VOLATILE,
   BTF_KIND_CONST, BTF_KIND_RESTRICT:
     the name must be null
 . BTF_KIND_STRUCT, BTF_KIND_UNION: the struct/member name
     is either null or a valid identifier
 . BTF_KIND_ENUM: the enum type name is either null or a valid
     identifier; the enumerator name must be a valid identifier.
 . BTF_KIND_FWD: the name must be a valid identifier
 . BTF_KIND_TYPEDEF: the name must be a valid identifier

For those places a valid name is required, the name must be
a valid C identifier. This can be relaxed later if we found
use cases for a different (non-C) frontend.

Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Acked-by: Martin KaFai Lau 
Signed-off-by: Yonghong Song 
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

bpf: btf: implement btf_name_valid_identifier()

2019-12-13T07:52:09+00:00

[ Upstream commit cdbb096adddb3f42584cecb5ec2e07c26815b71f ]

Function btf_name_valid_identifier() have been implemented in
bpf-next commit 2667a2626f4d ("bpf: btf: Add BTF_KIND_FUNC and
BTF_KIND_FUNC_PROTO"). Backport this function so later patch
can use it.

Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Signed-off-by: Yonghong Song 
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

bpf, btf: fix a missing check bug in btf_parse

2019-12-01T08:17:01+00:00

[ Upstream commit 4a6998aff82a20a1aece86a186d8e5263f8b2315 ]

Wenwen Wang reported:

  In btf_parse(), the header of the user-space btf data 'btf_data'
  is firstly parsed and verified through btf_parse_hdr().
  In btf_parse_hdr(), the header is copied from user-space 'btf_data'
  to kernel-space 'btf->hdr' and then verified. If no error happens
  during the verification process, the whole data of 'btf_data',
  including the header, is then copied to 'data' in btf_parse(). It
  is obvious that the header is copied twice here. More importantly,
  no check is enforced after the second copy to make sure the headers
  obtained in these two copies are same. Given that 'btf_data' resides
  in the user space, a malicious user can race to modify the header
  between these two copies. By doing so, the user can inject
  inconsistent data, which can cause undefined behavior of the
  kernel and introduce potential security risk.

This issue is similar to the one fixed in commit 8af03d1ae2e1 ("bpf:
btf: Fix a missing check bug"). To fix it, this patch copies the user
'btf_data' *before* parsing / verifying the BTF header.

Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Signed-off-by: Martin KaFai Lau 
Co-developed-by: Wenwen Wang 
Acked-by: Song Liu 
Signed-off-by: Daniel Borkmann 
Signed-off-by: Sasha Levin

bpf: btf: Fix a missing check bug

2019-11-24T07:20:53+00:00

[ Upstream commit 8af03d1ae2e154a8be3631e8694b87007e1bdbc2 ]

In btf_parse_hdr(), the length of the btf data header is firstly copied
from the user space to 'hdr_len' and checked to see whether it is larger
than 'btf_data_size'. If yes, an error code EINVAL is returned. Otherwise,
the whole header is copied again from the user space to 'btf->hdr'.
However, after the second copy, there is no check between
'btf->hdr->hdr_len' and 'hdr_len' to confirm that the two copies get the
same value. Given that the btf data is in the user space, a malicious user
can race to change the data between the two copies. By doing so, the user
can provide malicious data to the kernel and cause undefined behavior.

This patch adds a necessary check after the second copy, to make sure
'btf->hdr->hdr_len' has the same value as 'hdr_len'. Otherwise, an error
code EINVAL will be returned.

Signed-off-by: Wenwen Wang 
Acked-by: Song Liu 
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

bpf: btf: Fix end boundary calculation for type section

2018-09-12T20:00:23+00:00

The end boundary math for type section is incorrect in
btf_check_all_metas().  It just happens that hdr->type_off
is always 0 for now because there are only two sections
(type and string) and string section must be at the end (ensured
in btf_parse_str_sec).

However, type_off may not be 0 if a new section would be added later.
This patch fixes it.

Fixes: f80442a4cd18 ("bpf: btf: Change how section is supported in btf_header")
Reported-by: Dmitry Vyukov 
Signed-off-by: Martin KaFai Lau 
Acked-by: Yonghong Song 
Signed-off-by: Daniel Borkmann

bpf: btf: Ensure the member->offset is in the right order

2018-07-23T23:20:44+00:00

This patch ensures the member->offset of a struct
is in the correct order (i.e the later member's offset cannot
go backward).

The current "pahole -J" BTF encoder does not generate something
like this.  However, checking this can ensure future encoder
will not violate this.

Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Signed-off-by: Martin KaFai Lau 
Acked-by: Yonghong Song 
Signed-off-by: Daniel Borkmann

bpf: btf: Clean up BTF_INT_BITS() in uapi btf.h

2018-07-20T08:25:48+00:00

This patch shrinks the BTF_INT_BITS() mask.  The current
btf_int_check_meta() ensures the nr_bits of an integer
cannot exceed 64.  Hence, it is mostly an uapi cleanup.

The actual btf usage (i.e. seq_show()) is also modified
to use u8 instead of u16.  The verification (e.g. btf_int_check_meta())
path stays as is to deal with invalid BTF situation.

Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Signed-off-by: Martin KaFai Lau 
Signed-off-by: Daniel Borkmann