1. 09 Feb, 2022 9 commits
  2. 08 Feb, 2022 16 commits
  3. 07 Feb, 2022 6 commits
  4. 05 Feb, 2022 1 commit
    • Yonghong Song's avatar
      libbpf: Fix build issue with llvm-readelf · 0908a66a
      Yonghong Song authored
      There are cases where clang compiler is packaged in a way
      readelf is a symbolic link to llvm-readelf. In such cases,
      llvm-readelf will be used instead of default binutils readelf,
      and the following error will appear during libbpf build:
      
        Warning: Num of global symbols in
         /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/sharedobjs/libbpf-in.o (367)
         does NOT match with num of versioned symbols in
         /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.so libbpf.map (383).
         Please make sure all LIBBPF_API symbols are versioned in libbpf.map.
        --- /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf_global_syms.tmp ...
        +++ /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf_versioned_syms.tmp ...
        @@ -324,6 +324,22 @@
         btf__str_by_offset
         btf__type_by_id
         btf__type_cnt
        +LIBBPF_0.0.1
        +LIBBPF_0.0.2
        +LIBBPF_0.0.3
        +LIBBPF_0.0.4
        +LIBBPF_0.0.5
        +LIBBPF_0.0.6
        +LIBBPF_0.0.7
        +LIBBPF_0.0.8
        +LIBBPF_0.0.9
        +LIBBPF_0.1.0
        +LIBBPF_0.2.0
        +LIBBPF_0.3.0
        +LIBBPF_0.4.0
        +LIBBPF_0.5.0
        +LIBBPF_0.6.0
        +LIBBPF_0.7.0
         libbpf_attach_type_by_name
         libbpf_find_kernel_btf
         libbpf_find_vmlinux_btf_id
        make[2]: *** [Makefile:184: check_abi] Error 1
        make[1]: *** [Makefile:140: all] Error 2
      
      The above failure is due to different printouts for some ABS
      versioned symbols. For example, with the same libbpf.so,
        $ /bin/readelf --dyn-syms --wide tools/lib/bpf/libbpf.so | grep "LIBBPF" | grep ABS
           134: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS LIBBPF_0.5.0
           202: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS LIBBPF_0.6.0
           ...
        $ /opt/llvm/bin/readelf --dyn-syms --wide tools/lib/bpf/libbpf.so | grep "LIBBPF" | grep ABS
           134: 0000000000000000     0 OBJECT  GLOBAL DEFAULT   ABS LIBBPF_0.5.0@@LIBBPF_0.5.0
           202: 0000000000000000     0 OBJECT  GLOBAL DEFAULT   ABS LIBBPF_0.6.0@@LIBBPF_0.6.0
           ...
      The binutils readelf doesn't print out the symbol LIBBPF_* version and llvm-readelf does.
      Such a difference caused libbpf build failure with llvm-readelf.
      
      The proposed fix filters out all ABS symbols as they are not part of the comparison.
      This works for both binutils readelf and llvm-readelf.
      Reported-by: default avatarDelyan Kratunov <delyank@fb.com>
      Signed-off-by: default avatarYonghong Song <yhs@fb.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Link: https://lore.kernel.org/bpf/20220204214355.502108-1-yhs@fb.com
      0908a66a
  5. 04 Feb, 2022 4 commits
  6. 03 Feb, 2022 4 commits
    • Yonghong Song's avatar
      selftests/bpf: Add a selftest for invalid func btf with btf decl_tag · cf1a4cbc
      Yonghong Song authored
      Added a selftest similar to [1] which exposed a kernel bug.
      Without the fix in the previous patch, the similar kasan error will appear.
      
        [1] https://lore.kernel.org/bpf/0000000000009b6eaa05d71a8c06@google.com/Signed-off-by: default avatarYonghong Song <yhs@fb.com>
      Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Link: https://lore.kernel.org/bpf/20220203191732.742285-1-yhs@fb.com
      cf1a4cbc
    • Yonghong Song's avatar
      bpf: Fix a btf decl_tag bug when tagging a function · d7e7b42f
      Yonghong Song authored
      syzbot reported a btf decl_tag bug with stack trace below:
      
        general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
        KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
        CPU: 0 PID: 3592 Comm: syz-executor914 Not tainted 5.16.0-syzkaller-11424-gb7892f7d #0
        Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
        RIP: 0010:btf_type_vlen include/linux/btf.h:231 [inline]
        RIP: 0010:btf_decl_tag_resolve+0x83e/0xaa0 kernel/bpf/btf.c:3910
        ...
        Call Trace:
         <TASK>
         btf_resolve+0x251/0x1020 kernel/bpf/btf.c:4198
         btf_check_all_types kernel/bpf/btf.c:4239 [inline]
         btf_parse_type_sec kernel/bpf/btf.c:4280 [inline]
         btf_parse kernel/bpf/btf.c:4513 [inline]
         btf_new_fd+0x19fe/0x2370 kernel/bpf/btf.c:6047
         bpf_btf_load kernel/bpf/syscall.c:4039 [inline]
         __sys_bpf+0x1cbb/0x5970 kernel/bpf/syscall.c:4679
         __do_sys_bpf kernel/bpf/syscall.c:4738 [inline]
         __se_sys_bpf kernel/bpf/syscall.c:4736 [inline]
         __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4736
         do_syscall_x64 arch/x86/entry/common.c:50 [inline]
         do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
         entry_SYSCALL_64_after_hwframe+0x44/0xae
      
      The kasan error is triggered with an illegal BTF like below:
         type 0: void
         type 1: int
         type 2: decl_tag to func type 3
         type 3: func to func_proto type 8
      The total number of types is 4 and the type 3 is illegal
      since its func_proto type is out of range.
      
      Currently, the target type of decl_tag can be struct/union, var or func.
      Both struct/union and var implemented their own 'resolve' callback functions
      and hence handled properly in kernel.
      But func type doesn't have 'resolve' callback function. When
      btf_decl_tag_resolve() tries to check func type, it tries to get
      vlen of its func_proto type, which triggered the above kasan error.
      
      To fix the issue, btf_decl_tag_resolve() needs to do btf_func_check()
      before trying to accessing func_proto type.
      In the current implementation, func type is checked with
      btf_func_check() in the main checking function btf_check_all_types().
      To fix the above kasan issue, let us implement 'resolve' callback
      func type properly. The 'resolve' callback will be also called
      in btf_check_all_types() for func types.
      
      Fixes: b5ea834d ("bpf: Support for new btf kind BTF_KIND_TAG")
      Reported-by: syzbot+53619be9444215e785ed@syzkaller.appspotmail.com
      Signed-off-by: default avatarYonghong Song <yhs@fb.com>
      Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Link: https://lore.kernel.org/bpf/20220203191727.741862-1-yhs@fb.com
      d7e7b42f
    • Delyan Kratunov's avatar
      libbpf: Deprecate priv/set_priv storage · ca33aa4e
      Delyan Kratunov authored
      Arbitrary storage via bpf_*__set_priv/__priv is being deprecated
      without a replacement ([1]). perf uses this capability, but most of
      that is going away with the removal of prologue generation ([2]).
      perf is already suppressing deprecation warnings, so the remaining
      cleanup will happen separately.
      
        [1]: Closes: https://github.com/libbpf/libbpf/issues/294
        [2]: https://lore.kernel.org/bpf/20220123221932.537060-1-jolsa@kernel.org/Signed-off-by: default avatarDelyan Kratunov <delyank@fb.com>
      Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
      Link: https://lore.kernel.org/bpf/20220203180032.1921580-1-delyank@fb.com
      ca33aa4e
    • Lorenzo Bianconi's avatar
      bpf: test_run: Fix OOB access in bpf_prog_test_run_xdp · a6763080
      Lorenzo Bianconi authored
      Fix the following kasan issue reported by syzbot:
      
      BUG: KASAN: slab-out-of-bounds in __skb_frag_set_page include/linux/skbuff.h:3242 [inline]
      BUG: KASAN: slab-out-of-bounds in bpf_prog_test_run_xdp+0x10ac/0x1150 net/bpf/test_run.c:972
      Write of size 8 at addr ffff888048c75000 by task syz-executor.5/23405
      
      CPU: 1 PID: 23405 Comm: syz-executor.5 Not tainted 5.16.0-syzkaller #0
      Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Call Trace:
       <TASK>
       __dump_stack lib/dump_stack.c:88 [inline]
       dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
       print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
       __kasan_report mm/kasan/report.c:442 [inline]
       kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
       __skb_frag_set_page include/linux/skbuff.h:3242 [inline]
       bpf_prog_test_run_xdp+0x10ac/0x1150 net/bpf/test_run.c:972
       bpf_prog_test_run kernel/bpf/syscall.c:3356 [inline]
       __sys_bpf+0x1858/0x59a0 kernel/bpf/syscall.c:4658
       __do_sys_bpf kernel/bpf/syscall.c:4744 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:4742 [inline]
       __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4742
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae
      RIP: 0033:0x7f4ea30dd059
      RSP: 002b:00007f4ea1a52168 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
      RAX: ffffffffffffffda RBX: 00007f4ea31eff60 RCX: 00007f4ea30dd059
      RDX: 0000000000000048 RSI: 0000000020000000 RDI: 000000000000000a
      RBP: 00007f4ea313708d R08: 0000000000000000 R09: 0000000000000000
      R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
      R13: 00007ffc8367c5af R14: 00007f4ea1a52300 R15: 0000000000022000
       </TASK>
      
      Allocated by task 23405:
       kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38
       kasan_set_track mm/kasan/common.c:46 [inline]
       set_alloc_info mm/kasan/common.c:437 [inline]
       ____kasan_kmalloc mm/kasan/common.c:516 [inline]
       ____kasan_kmalloc mm/kasan/common.c:475 [inline]
       __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:525
       kmalloc include/linux/slab.h:586 [inline]
       kzalloc include/linux/slab.h:715 [inline]
       bpf_test_init.isra.0+0x9f/0x150 net/bpf/test_run.c:411
       bpf_prog_test_run_xdp+0x2f8/0x1150 net/bpf/test_run.c:941
       bpf_prog_test_run kernel/bpf/syscall.c:3356 [inline]
       __sys_bpf+0x1858/0x59a0 kernel/bpf/syscall.c:4658
       __do_sys_bpf kernel/bpf/syscall.c:4744 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:4742 [inline]
       __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4742
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae
      
      The buggy address belongs to the object at ffff888048c74000
       which belongs to the cache kmalloc-4k of size 4096
      The buggy address is located 0 bytes to the right of
       4096-byte region [ffff888048c74000, ffff888048c75000)
      The buggy address belongs to the page:
      page:ffffea0001231c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x48c70
      head:ffffea0001231c00 order:3 compound_mapcount:0 compound_pincount:0
      flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
      raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010c42140
      raw: 0000000000000000 0000000080040004 00000001ffffffff 0000000000000000
      page dumped because: kasan: bad access detected
      page_owner tracks the page as allocated
       prep_new_page mm/page_alloc.c:2434 [inline]
       get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
       __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
       alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271
       alloc_slab_page mm/slub.c:1799 [inline]
       allocate_slab mm/slub.c:1944 [inline]
       new_slab+0x28a/0x3b0 mm/slub.c:2004
       ___slab_alloc+0x87c/0xe90 mm/slub.c:3018
       __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105
       slab_alloc_node mm/slub.c:3196 [inline]
       __kmalloc_node_track_caller+0x2cb/0x360 mm/slub.c:4957
       kmalloc_reserve net/core/skbuff.c:354 [inline]
       __alloc_skb+0xde/0x340 net/core/skbuff.c:426
       alloc_skb include/linux/skbuff.h:1159 [inline]
       nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:745 [inline]
       nsim_dev_trap_report drivers/net/netdevsim/dev.c:802 [inline]
       nsim_dev_trap_report_work+0x29a/0xbc0 drivers/net/netdevsim/dev.c:843
       process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
       worker_thread+0x657/0x1110 kernel/workqueue.c:2454
       kthread+0x2e9/0x3a0 kernel/kthread.c:377
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
      page last free stack trace:
       reset_page_owner include/linux/page_owner.h:24 [inline]
       free_pages_prepare mm/page_alloc.c:1352 [inline]
       free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404
       free_unref_page_prepare mm/page_alloc.c:3325 [inline]
       free_unref_page+0x19/0x690 mm/page_alloc.c:3404
       qlink_free mm/kasan/quarantine.c:157 [inline]
       qlist_free_all+0x6d/0x160 mm/kasan/quarantine.c:176
       kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
       __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:447
       kasan_slab_alloc include/linux/kasan.h:260 [inline]
       slab_post_alloc_hook mm/slab.h:732 [inline]
       slab_alloc_node mm/slub.c:3230 [inline]
       slab_alloc mm/slub.c:3238 [inline]
       kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3243
       getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
       getname_flags include/linux/audit.h:323 [inline]
       getname+0x8e/0xd0 fs/namei.c:217
       do_sys_openat2+0xf5/0x4d0 fs/open.c:1208
       do_sys_open fs/open.c:1230 [inline]
       __do_sys_openat fs/open.c:1246 [inline]
       __se_sys_openat fs/open.c:1241 [inline]
       __x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae
      
      Memory state around the buggy address:
       ffff888048c74f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
       ffff888048c74f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                         ^
       ffff888048c75080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
       ffff888048c75100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
      ==================================================================
      
      Fixes: 1c194998 ("bpf: introduce frags support to bpf_prog_test_run_xdp()")
      Reported-by: syzbot+6d70ca7438345077c549@syzkaller.appspotmail.com
      Signed-off-by: default avatarLorenzo Bianconi <lorenzo@kernel.org>
      Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      Link: https://lore.kernel.org/bpf/688c26f9dd6e885e58e8e834ede3f0139bb7fa95.1643835097.git.lorenzo@kernel.org
      a6763080