1. 19 1月, 2018 1 次提交
  2. 11 1月, 2018 1 次提交
    • D
      bpf: arsh is not supported in 32 bit alu thus reject it · 7891a87e
      Daniel Borkmann 提交于
      The following snippet was throwing an 'unknown opcode cc' warning
      in BPF interpreter:
      
        0: (18) r0 = 0x0
        2: (7b) *(u64 *)(r10 -16) = r0
        3: (cc) (u32) r0 s>>= (u32) r0
        4: (95) exit
      
      Although a number of JITs do support BPF_ALU | BPF_ARSH | BPF_{K,X}
      generation, not all of them do and interpreter does neither. We can
      leave existing ones and implement it later in bpf-next for the
      remaining ones, but reject this properly in verifier for the time
      being.
      
      Fixes: 17a52670 ("bpf: verifier (add verifier core)")
      Reported-by: syzbot+93c4904c5c70348a6890@syzkaller.appspotmail.com
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      7891a87e
  3. 07 1月, 2018 2 次提交
  4. 31 12月, 2017 1 次提交
  5. 28 12月, 2017 3 次提交
    • A
      bpf: fix max call depth check · aada9ce6
      Alexei Starovoitov 提交于
      fix off by one error in max call depth check
      and add a test
      
      Fixes: f4d7e40a ("bpf: introduce function calls (verification)")
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      aada9ce6
    • A
      selftests/bpf: additional stack depth tests · 6b86c421
      Alexei Starovoitov 提交于
      to test inner logic of stack depth tracking
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      6b86c421
    • J
      bpf: selftest for late caller stack size increase · 6b80ad29
      Jann Horn 提交于
      This checks that it is not possible to bypass the total stack size check in
      update_stack_depth() by calling a function that uses a large amount of
      stack memory *before* using a large amount of stack memory in the caller.
      
      Currently, the first added testcase causes a rejection as expected, but
      the second testcase is (AFAICS incorrectly) accepted:
      
      [...]
      #483/p calls: stack overflow using two frames (post-call access) FAIL
      Unexpected success to load!
      0: (85) call pc+2
      caller:
       R10=fp0,call_-1
      callee:
       frame1: R1=ctx(id=0,off=0,imm=0) R10=fp0,call_0
      3: (72) *(u8 *)(r10 -300) = 0
      4: (b7) r0 = 0
      5: (95) exit
      returning from callee:
       frame1: R0_w=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0,call_0
      to caller at 1:
       R0_w=inv0 R10=fp0,call_-1
      
      from 5 to 1: R0=inv0 R10=fp0,call_-1
      1: (72) *(u8 *)(r10 -300) = 0
      2: (95) exit
      processed 6 insns, stack depth 300+300
      [...]
      Summary: 704 PASSED, 1 FAILED
      
      AFAICS the JIT-generated code for the second testcase shows that this
      really causes the stack pointer to be decremented by 300+300:
      
      first function:
      00000000  55                push rbp
      00000001  4889E5            mov rbp,rsp
      00000004  4881EC58010000    sub rsp,0x158
      0000000B  4883ED28          sub rbp,byte +0x28
      [...]
      00000025  E89AB3AFE5        call 0xffffffffe5afb3c4
      0000002A  C685D4FEFFFF00    mov byte [rbp-0x12c],0x0
      [...]
      00000041  4883C528          add rbp,byte +0x28
      00000045  C9                leave
      00000046  C3                ret
      
      second function:
      00000000  55                push rbp
      00000001  4889E5            mov rbp,rsp
      00000004  4881EC58010000    sub rsp,0x158
      0000000B  4883ED28          sub rbp,byte +0x28
      [...]
      00000025  C685D4FEFFFF00    mov byte [rbp-0x12c],0x0
      [...]
      0000003E  4883C528          add rbp,byte +0x28
      00000042  C9                leave
      00000043  C3                ret
      Signed-off-by: NJann Horn <jannh@google.com>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      6b80ad29
  6. 24 12月, 2017 1 次提交
    • G
      bpf: fix stacksafe exploration when comparing states · fd05e57b
      Gianluca Borello 提交于
      Commit cc2b14d5 ("bpf: teach verifier to recognize zero initialized
      stack") introduced a very relaxed check when comparing stacks of different
      states, effectively returning a positive result in many cases where it
      shouldn't.
      
      This can create problems in cases such as this following C pseudocode:
      
      long var;
      long *x = bpf_map_lookup(...);
      if (!x)
              return;
      
      if (*x != 0xbeef)
              var = 0;
      else
              var = 1;
      
      /* This is the key part, calling a helper causes an explored state
       * to be saved with the information that "var" is on the stack as
       * STACK_ZERO, since the helper is first met by the verifier after
       * the "var = 0" assignment. This state will however be wrongly used
       * also for the "var = 1" case, so the verifier assumes "var" is always
       * 0 and will replace the NULL assignment with nops, because the
       * search pruning prevents it from exploring the faulty branch.
       */
      bpf_ktime_get_ns();
      
      if (var)
              *(long *)0 = 0xbeef;
      
      Fix the issue by making sure that the stack is fully explored before
      returning a positive comparison result.
      
      Also attach a couple tests that highlight the bad behavior. In the first
      test, without this fix instructions 16 and 17 are replaced with nops
      instead of being rejected by the verifier.
      
      The second test, instead, allows a program to make a potentially illegal
      read from the stack.
      
      Fixes: cc2b14d5 ("bpf: teach verifier to recognize zero initialized stack")
      Signed-off-by: NGianluca Borello <g.borello@gmail.com>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      fd05e57b
  7. 22 12月, 2017 1 次提交
  8. 21 12月, 2017 3 次提交
    • Y
      tools/bpf: adjust rlimit RLIMIT_MEMLOCK for test_dev_cgroup · c475ffad
      Yonghong Song 提交于
      The default rlimit RLIMIT_MEMLOCK is 64KB. In certain cases,
      e.g. in a test machine mimicking our production system, this test may
      fail due to unable to charge the required memory for prog load:
      
        $ ./test_dev_cgroup
        libbpf: load bpf program failed: Operation not permitted
        libbpf: failed to load program 'cgroup/dev'
        libbpf: failed to load object './dev_cgroup.o'
        Failed to load DEV_CGROUP program
        ...
      
      Changing the default rlimit RLIMIT_MEMLOCK to unlimited
      makes the test pass.
      
      This patch also fixed a problem where when bpf_prog_load fails,
      cleanup_cgroup_environment() should not be called since
      setup_cgroup_environment() has not been invoked. Otherwise,
      the following confusing message will appear:
        ...
        (/home/yhs/local/linux/tools/testing/selftests/bpf/cgroup_helpers.c:95:
         errno: No such file or directory) Opening Cgroup Procs: /mnt/cgroup.procs
        ...
      Signed-off-by: NYonghong Song <yhs@fb.com>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      c475ffad
    • A
      bpf: do not allow root to mangle valid pointers · 82abbf8d
      Alexei Starovoitov 提交于
      Do not allow root to convert valid pointers into unknown scalars.
      In particular disallow:
       ptr &= reg
       ptr <<= reg
       ptr += ptr
      and explicitly allow:
       ptr -= ptr
      since pkt_end - pkt == length
      
      1.
      This minimizes amount of address leaks root can do.
      In the future may need to further tighten the leaks with kptr_restrict.
      
      2.
      If program has such pointer math it's likely a user mistake and
      when verifier complains about it right away instead of many instructions
      later on invalid memory access it's easier for users to fix their progs.
      
      3.
      when register holding a pointer cannot change to scalar it allows JITs to
      optimize better. Like 32-bit archs could use single register for pointers
      instead of a pair required to hold 64-bit scalars.
      
      4.
      reduces architecture dependent behavior. Since code:
      r1 = r10;
      r1 &= 0xff;
      if (r1 ...)
      will behave differently arm64 vs x64 and offloaded vs native.
      
      A significant chunk of ptr mangling was allowed by
      commit f1174f77 ("bpf/verifier: rework value tracking")
      yet some of it was allowed even earlier.
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      82abbf8d
    • J
      selftests/bpf: add tests for recent bugfixes · 2255f8d5
      Jann Horn 提交于
      These tests should cover the following cases:
      
       - MOV with both zero-extended and sign-extended immediates
       - implicit truncation of register contents via ALU32/MOV32
       - implicit 32-bit truncation of ALU32 output
       - oversized register source operand for ALU32 shift
       - right-shift of a number that could be positive or negative
       - map access where adding the operation size to the offset causes signed
         32-bit overflow
       - direct stack access at a ~4GiB offset
      
      Also remove the F_LOAD_WITH_STRICT_ALIGNMENT flag from a bunch of tests
      that should fail independent of what flags userspace passes.
      Signed-off-by: NJann Horn <jannh@google.com>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      2255f8d5
  9. 20 12月, 2017 1 次提交
  10. 19 12月, 2017 1 次提交
  11. 18 12月, 2017 5 次提交
  12. 16 12月, 2017 1 次提交
  13. 13 12月, 2017 3 次提交
  14. 12 12月, 2017 1 次提交
  15. 05 12月, 2017 1 次提交
  16. 03 12月, 2017 1 次提交
  17. 01 12月, 2017 2 次提交
  18. 23 11月, 2017 1 次提交
    • G
      bpf: introduce ARG_PTR_TO_MEM_OR_NULL · db1ac496
      Gianluca Borello 提交于
      With the current ARG_PTR_TO_MEM/ARG_PTR_TO_UNINIT_MEM semantics, an helper
      argument can be NULL when the next argument type is ARG_CONST_SIZE_OR_ZERO
      and the verifier can prove the value of this next argument is 0. However,
      most helpers are just interested in handling <!NULL, 0>, so forcing them to
      deal with <NULL, 0> makes the implementation of those helpers more
      complicated for no apparent benefits, requiring them to explicitly handle
      those corner cases with checks that bpf programs could start relying upon,
      preventing the possibility of removing them later.
      
      Solve this by making ARG_PTR_TO_MEM/ARG_PTR_TO_UNINIT_MEM never accept NULL
      even when ARG_CONST_SIZE_OR_ZERO is set, and introduce a new argument type
      ARG_PTR_TO_MEM_OR_NULL to explicitly deal with the NULL case.
      
      Currently, the only helper that needs this is bpf_csum_diff_proto(), so
      change arg1 and arg3 to this new type as well.
      
      Also add a new battery of tests that explicitly test the
      !ARG_PTR_TO_MEM_OR_NULL combination: all the current ones testing the
      various <NULL, 0> variations are focused on bpf_csum_diff, so cover also
      other helpers.
      Signed-off-by: NGianluca Borello <g.borello@gmail.com>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      db1ac496
  19. 22 11月, 2017 1 次提交
    • Y
      bpf: change bpf_probe_write_user to bpf_trace_printk in test_verifier · f1a8b8e3
      Yonghong Song 提交于
      There are four tests in test_verifier using bpf_probe_write_user
      helper. These four tests will emit the following kernel messages
        [   12.974753] test_verifier[220] is installing a program with bpf_probe_write_user
                                          helper that may corrupt user memory!
        [   12.979285] test_verifier[220] is installing a program with bpf_probe_write_user
                                          helper that may corrupt user memory!
        ......
      
      This may confuse certain users. This patch replaces bpf_probe_write_user
      with bpf_trace_printk. The test_verifier already uses bpf_trace_printk
      earlier in the test and a trace_printk warning message has been printed.
      So this patch does not emit any more kernel messages.
      
      Fixes: b6ff6391 ("bpf: fix and add test cases for ARG_CONST_SIZE_OR_ZERO semantics change")
      Signed-off-by: NYonghong Song <yhs@fb.com>
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      f1a8b8e3
  20. 14 11月, 2017 1 次提交
  21. 11 11月, 2017 2 次提交
  22. 05 11月, 2017 2 次提交
  23. 02 11月, 2017 3 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman 提交于
      Many source files in the tree are missing licensing information, which
      makes it harder for compliance tools to determine the correct license.
      
      By default all files without license information are under the default
      license of the kernel, which is GPL version 2.
      
      Update the files which contain no license information with the 'GPL-2.0'
      SPDX license identifier.  The SPDX identifier is a legally binding
      shorthand, which can be used instead of the full boiler plate text.
      
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.
      
      How this work was done:
      
      Patches were generated and checked against linux-4.14-rc6 for a subset of
      the use cases:
       - file had no licensing information it it.
       - file was a */uapi/* one with no licensing information in it,
       - file was a */uapi/* one with existing licensing information,
      
      Further patches will be generated in subsequent months to fix up cases
      where non-standard license headers were used, and references to license
      had to be inferred by heuristics based on keywords.
      
      The analysis to determine which SPDX License Identifier to be applied to
      a file was done in a spreadsheet of side by side results from of the
      output of two independent scanners (ScanCode & Windriver) producing SPDX
      tag:value files created by Philippe Ombredanne.  Philippe prepared the
      base worksheet, and did an initial spot review of a few 1000 files.
      
      The 4.13 kernel was the starting point of the analysis with 60,537 files
      assessed.  Kate Stewart did a file by file comparison of the scanner
      results in the spreadsheet to determine which SPDX license identifier(s)
      to be applied to the file. She confirmed any determination that was not
      immediately clear with lawyers working with the Linux Foundation.
      
      Criteria used to select files for SPDX license identifier tagging was:
       - Files considered eligible had to be source code files.
       - Make and config files were included as candidates if they contained >5
         lines of source
       - File already had some variant of a license header in it (even if <5
         lines).
      
      All documentation files were explicitly excluded.
      
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
      
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
      
         For non */uapi/* files that summary was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0                                              11139
      
         and resulted in the first patch in this series.
      
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0 WITH Linux-syscall-note                        930
      
         and resulted in the second patch in this series.
      
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|------
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
      
         and that resulted in the third patch in this series.
      
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
      
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
      
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
      
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
      
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
    • D
      bpf: add test cases to bpf selftests to cover all meta tests · 634eab11
      Daniel Borkmann 提交于
      Lets also add test cases to cover all possible data_meta access tests
      for good/bad access cases so we keep tracking them.
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      634eab11
    • D
      bpf: minor cleanups after merge · b06723da
      Daniel Borkmann 提交于
      Two minor cleanups after Dave's recent merge in f8ddadc4
      ("Merge git://git.kernel.org...") of net into net-next in
      order to get the code in line with what was done originally
      in the net tree: i) use max() instead of max_t() since both
      ranges are u16, ii) don't split the direct access test cases
      in the middle with bpf_exit test cases from 390ee7e2
      ("bpf: enforce return code for cgroup-bpf programs").
      Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b06723da
  24. 01 11月, 2017 1 次提交