- 05 Dec, 2023 16 commits
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Andrii Nakryiko authored
Add tests validating that STACK_ZERO slots are preserved when slot is partially overwritten with subregister spill. Acked-by:
Eduard Zingerman <eddyz87@gmail.com> Signed-off-by:
Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20231205184248.1502704-6-andrii@kernel.orgSigned-off-by:
Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Instead of always forcing STACK_ZERO slots to STACK_MISC, preserve it in situations where this is possible. E.g., when spilling register as 1/2/4-byte subslots on the stack, all the remaining bytes in the stack slot do not automatically become unknown. If we knew they contained zeroes, we can preserve those STACK_ZERO markers. Add a helper mark_stack_slot_misc(), similar to scrub_spilled_slot(), but that doesn't overwrite either STACK_INVALID nor STACK_ZERO. Note that we need to take into account possibility of being in unprivileged mode, in which case STACK_INVALID is forced to STACK_MISC for correctness, as treating STACK_INVALID as equivalent STACK_MISC is only enabled in privileged mode. Acked-by:
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Andrii Nakryiko authored
When register is spilled onto a stack as a 1/2/4-byte register, we set slot_type[BPF_REG_SIZE - 1] (plus potentially few more below it, depending on actual spill size). So to check if some stack slot has spilled register we need to consult slot_type[7], not slot_type[0]. To avoid the need to remember and double-check this in the future, just use is_spilled_reg() helper. Fixes: 27113c59 ("bpf: Check the other end of slot_type for STACK_SPILL") Signed-off-by:
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Andrii Nakryiko authored
Add a new selftests that validates precision tracking for stack access instruction, using both r10-based and non-r10-based accesses. For non-r10 ones we also make sure to have non-zero var_off to validate that final stack offset is tracked properly in instruction history information inside verifier. Acked-by:
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Andrii Nakryiko authored
Use instruction (jump) history to record instructions that performed register spill/fill to/from stack, regardless if this was done through read-only r10 register, or any other register after copying r10 into it *and* potentially adjusting offset. To make this work reliably, we push extra per-instruction flags into instruction history, encoding stack slot index (spi) and stack frame number in extra 10 bit flags we take away from prev_idx in instruction history. We don't touch idx field for maximum performance, as it's checked most frequently during backtracking. This change removes basically the last remaining practical limitation of precision backtracking logic in BPF verifier. It fixes known deficiencies, but also opens up new opportunities to reduce number of verified states, explored in the subsequent patches. There are only three differences in selftests' BPF object files according to veristat, all in the positive direction (less states). File Program Insns (A) Insns (B) Insns (DIFF) States (A) States (B) States (DIFF) -------------------------------------- ------------- --------- --------- ------------- ---------- ---------- ------------- test_cls_redirect_dynptr.bpf.linked3.o cls_redirect 2987 2864 -123 (-4.12%) 240 231 -9 (-3.75%) xdp_synproxy_kern.bpf.linked3.o syncookie_tc 82848 82661 -187 (-0.23%) 5107 5073 -34 (-0.67%) xdp_synproxy_kern.bpf.linked3.o syncookie_xdp 85116 84964 -152 (-0.18%) 5162 5130 -32 (-0.62%) Note, I avoided renaming jmp_history to more generic insn_hist to minimize number of lines changed and potential merge conflicts between bpf and bpf-next trees. Notice also cur_hist_entry pointer reset to NULL at the beginning of instruction verification loop. This pointer avoids the problem of relying on last jump history entry's insn_idx to determine whether we already have entry for current instruction or not. It can happen that we added jump history entry because current instruction is_jmp_point(), but also we need to add instruction flags for stack access. In this case, we don't want to entries, so we need to reuse last added entry, if it is present. Relying on insn_idx comparison has the same ambiguity problem as the one that was fixed recently in [0], so we avoid that. [0] https://patchwork.kernel.org/project/netdevbpf/patch/20231110002638.4168352-3-andrii@kernel.org/Acked-by:
Tao Lyu <tao.lyu@epfl.ch> Signed-off-by:
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Stanislav Fomichev authored
xdp_metadata test is flaky sometimes: verify_xsk_metadata:FAIL:rx_hash_type unexpected rx_hash_type: actual 8 != expected 0 Where 8 means XDP_RSS_TYPE_L4_ANY and is exported from veth driver only when 'skb->l4_hash' condition is met. This makes me think that the program is triggering again for some other packet. Let's have a filter, similar to xdp_hw_metadata, where we trigger XDP kfuncs only for UDP packets destined to port 8080. Signed-off-by:
Stanislav Fomichev <sdf@google.com> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20231204174423.3460052-1-sdf@google.com
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Stanislav Fomichev authored
Not sure how I missed that. I even acknowledged it explicitly in the changelog [0]. Add the tag for real now. [0] https://lore.kernel.org/bpf/20231127190319.1190813-1-sdf@google.com/ Fixes: 11614723 ("xsk: Add option to calculate TX checksum in SW") Suggested-by:
Simon Horman <horms@kernel.org> Signed-off-by:
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Dave Marchevsky authored
There was some confusion amongst Meta sched_ext folks regarding whether stashing bpf_rb_root - the tree itself, rather than a single node - was supported. This patch adds a small test which demonstrates this functionality: a local kptr with rb_root is created, a node is created and added to the tree, then the tree is kptr_xchg'd into a mapval. Signed-off-by:
Dave Marchevsky <davemarchevsky@fb.com> Signed-off-by:
Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/bpf/20231204211722.571346-1-davemarchevsky@fb.com
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Alexei Starovoitov authored
Hou Tao says: ==================== bpf: Fix the release of inner map From: Hou Tao <houtao1@huawei.com> Hi, The patchset aims to fix the release of inner map in map array or map htab. The release of inner map is different with normal map. For normal map, the map is released after the bpf program which uses the map is destroyed, because the bpf program tracks the used maps. However bpf program can not track the used inner map because these inner map may be updated or deleted dynamically, and for now the ref-counter of inner map is decreased after the inner map is remove from outer map, so the inner map may be freed before the bpf program, which is accessing the inner map, exits and there will be use-after-free problem as demonstrated by patch #6. The patchset fixes the problem by deferring the release of inner map. The freeing of inner map is deferred according to the sleepable attributes of the bpf programs which own the outer map. Patch #1 fixes the warning when running the newly-added selftest under interpreter mode. Patch #2 adds more parameters to .map_fd_put_ptr() to prepare for the fix. Patch #3 fixes the incorrect value of need_defer when freeing the fd array. Patch #4 fixes the potential use-after-free problem by using call_rcu_tasks_trace() and call_rcu() to wait for one tasks trace RCU GP and one RCU GP unconditionally. Patch #5 optimizes the free of inner map by removing the unnecessary RCU GP waiting. Patch #6 adds a selftest to demonstrate the potential use-after-free problem. Patch #7 updates a selftest to update outer map in syscall bpf program. Please see individual patches for more details. And comments are always welcome. Change Log: v5: * patch #3: rename fd_array_map_delete_elem_with_deferred_free() to __fd_array_map_delete_elem() (Alexei) * patch #5: use atomic64_t instead of atomic_t to prevent potential overflow (Alexei) * patch #7: use ptr_to_u64() helper instead of force casting to initialize pointers in bpf_attr (Alexei) v4: https://lore.kernel.org/bpf/20231130140120.1736235-1-houtao@huaweicloud.com * patch #2: don't use "deferred", use "need_defer" uniformly * patch #3: newly-added, fix the incorrect value of need_defer during fd array free. * patch #4: doesn't consider the case in which bpf map is not used by any bpf program and only use sleepable_refcnt to remove unnecessary tasks trace RCU GP (Alexei) * patch #4: remove memory barriers added due to cautiousness (Alexei) v3: https://lore.kernel.org/bpf/20231124113033.503338-1-houtao@huaweicloud.com * multiple variable renamings (Martin) * define BPF_MAP_RCU_GP/BPF_MAP_RCU_TT_GP as bit (Martin) * use call_rcu() and its variants instead of synchronize_rcu() (Martin) * remove unnecessary mask in bpf_map_free_deferred() (Martin) * place atomic_or() and the related smp_mb() together (Martin) * add patch #6 to demonstrate that updating outer map in syscall program is dead-lock free (Alexei) * update comments about the memory barrier in bpf_map_fd_put_ptr() * update commit message for patch #3 and #4 to describe more details v2: https://lore.kernel.org/bpf/20231113123324.3914612-1-houtao@huaweicloud.com * defer the invocation of ops->map_free() instead of bpf_map_put() (Martin) * update selftest to make it being reproducible under JIT mode (Martin) * remove unnecessary preparatory patches v1: https://lore.kernel.org/bpf/20231107140702.1891778-1-houtao@huaweicloud.com ==================== Link: https://lore.kernel.org/r/20231204140425.1480317-1-houtao@huaweicloud.comSigned-off-by: -
Hou Tao authored
Syscall program is running with rcu_read_lock_trace being held, so if bpf_map_update_elem() or bpf_map_delete_elem() invokes synchronize_rcu_tasks_trace() when operating on an outer map, there will be dead-lock, so add a test to guarantee that it is dead-lock free. Signed-off-by:
Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20231204140425.1480317-8-houtao@huaweicloud.comSigned-off-by:
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Hou Tao authored
Add test cases to test the race between the destroy of inner map due to map-in-map update and the access of inner map in bpf program. The following 4 combinations are added: (1) array map in map array + bpf program (2) array map in map array + sleepable bpf program (3) array map in map htab + bpf program (4) array map in map htab + sleepable bpf program Before applying the fixes, when running `./test_prog -a map_in_map`, the following error was reported: ================================================================== BUG: KASAN: slab-use-after-free in array_map_update_elem+0x48/0x3e0 Read of size 4 at addr ffff888114f33824 by task test_progs/1858 CPU: 1 PID: 1858 Comm: test_progs Tainted: G O 6.6.0+ #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...... Call Trace: <TASK> dump_stack_lvl+0x4a/0x90 print_report+0xd2/0x620 kasan_report+0xd1/0x110 __asan_load4+0x81/0xa0 array_map_update_elem+0x48/0x3e0 bpf_prog_be94a9f26772f5b7_access_map_in_array+0xe6/0xf6 trace_call_bpf+0x1aa/0x580 kprobe_perf_func+0xdd/0x430 kprobe_dispatcher+0xa0/0xb0 kprobe_ftrace_handler+0x18b/0x2e0 0xffffffffc02280f7 RIP: 0010:__x64_sys_getpgid+0x1/0x30 ...... </TASK> Allocated by task 1857: kasan_save_stack+0x26/0x50 kasan_set_track+0x25/0x40 kasan_save_alloc_info+0x1e/0x30 __kasan_kmalloc+0x98/0xa0 __kmalloc_node+0x6a/0x150 __bpf_map_area_alloc+0x141/0x170 bpf_map_area_alloc+0x10/0x20 array_map_alloc+0x11f/0x310 map_create+0x28a/0xb40 __sys_bpf+0x753/0x37c0 __x64_sys_bpf+0x44/0x60 do_syscall_64+0x36/0xb0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 Freed by task 11: kasan_save_stack+0x26/0x50 kasan_set_track+0x25/0x40 kasan_save_free_info+0x2b/0x50 __kasan_slab_free+0x113/0x190 slab_free_freelist_hook+0xd7/0x1e0 __kmem_cache_free+0x170/0x260 kfree+0x9b/0x160 kvfree+0x2d/0x40 bpf_map_area_free+0xe/0x20 array_map_free+0x120/0x2c0 bpf_map_free_deferred+0xd7/0x1e0 process_one_work+0x462/0x990 worker_thread+0x370/0x670 kthread+0x1b0/0x200 ret_from_fork+0x3a/0x70 ret_from_fork_asm+0x1b/0x30 Last potentially related work creation: kasan_save_stack+0x26/0x50 __kasan_record_aux_stack+0x94/0xb0 kasan_record_aux_stack_noalloc+0xb/0x20 __queue_work+0x331/0x950 queue_work_on+0x75/0x80 bpf_map_put+0xfa/0x160 bpf_map_fd_put_ptr+0xe/0x20 bpf_fd_array_map_update_elem+0x174/0x1b0 bpf_map_update_value+0x2b7/0x4a0 __sys_bpf+0x2551/0x37c0 __x64_sys_bpf+0x44/0x60 do_syscall_64+0x36/0xb0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 Signed-off-by:
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Hou Tao authored
When removing the inner map from the outer map, the inner map will be freed after one RCU grace period and one RCU tasks trace grace period, so it is certain that the bpf program, which may access the inner map, has exited before the inner map is freed. However there is no need to wait for one RCU tasks trace grace period if the outer map is only accessed by non-sleepable program. So adding sleepable_refcnt in bpf_map and increasing sleepable_refcnt when adding the outer map into env->used_maps for sleepable program. Although the max number of bpf program is INT_MAX - 1, the number of bpf programs which are being loaded may be greater than INT_MAX, so using atomic64_t instead of atomic_t for sleepable_refcnt. When removing the inner map from the outer map, using sleepable_refcnt to decide whether or not a RCU tasks trace grace period is needed before freeing the inner map. Signed-off-by:
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Hou Tao authored
When updating or deleting an inner map in map array or map htab, the map may still be accessed by non-sleepable program or sleepable program. However bpf_map_fd_put_ptr() decreases the ref-counter of the inner map directly through bpf_map_put(), if the ref-counter is the last one (which is true for most cases), the inner map will be freed by ops->map_free() in a kworker. But for now, most .map_free() callbacks don't use synchronize_rcu() or its variants to wait for the elapse of a RCU grace period, so after the invocation of ops->map_free completes, the bpf program which is accessing the inner map may incur use-after-free problem. Fix the free of inner map by invoking bpf_map_free_deferred() after both one RCU grace period and one tasks trace RCU grace period if the inner map has been removed from the outer map before. The deferment is accomplished by using call_rcu() or call_rcu_tasks_trace() when releasing the last ref-counter of bpf map. The newly-added rcu_head field in bpf_map shares the same storage space with work field to reduce the size of bpf_map. Fixes: bba1dc0b ("bpf: Remove redundant synchronize_rcu.") Fixes: 638e4b82 ("bpf: Allows per-cpu maps and map-in-map in sleepable programs") Signed-off-by:
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Hou Tao authored
Both map deletion operation, map release and map free operation use fd_array_map_delete_elem() to remove the element from fd array and need_defer is always true in fd_array_map_delete_elem(). For the map deletion operation and map release operation, need_defer=true is necessary, because the bpf program, which accesses the element in fd array, may still alive. However for map free operation, it is certain that the bpf program which owns the fd array has already been exited, so setting need_defer as false is appropriate for map free operation. So fix it by adding need_defer parameter to bpf_fd_array_map_clear() and adding a new helper __fd_array_map_delete_elem() to handle the map deletion, map release and map free operations correspondingly. Signed-off-by:
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Hou Tao authored
map is the pointer of outer map, and need_defer needs some explanation. need_defer tells the implementation to defer the reference release of the passed element and ensure that the element is still alive before the bpf program, which may manipulate it, exits. The following three cases will invoke map_fd_put_ptr() and different need_defer values will be passed to these callers: 1) release the reference of the old element in the map during map update or map deletion. The release must be deferred, otherwise the bpf program may incur use-after-free problem, so need_defer needs to be true. 2) release the reference of the to-be-added element in the error path of map update. The to-be-added element is not visible to any bpf program, so it is OK to pass false for need_defer parameter. 3) release the references of all elements in the map during map release. Any bpf program which has access to the map must have been exited and released, so need_defer=false will be OK. These two parameters will be used by the following patches to fix the potential use-after-free problem for map-in-map. Signed-off-by:
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Hou Tao authored
These three bpf_map_{lookup,update,delete}_elem() helpers are also available for sleepable bpf program, so add the corresponding lock assertion for sleepable bpf program, otherwise the following warning will be reported when a sleepable bpf program manipulates bpf map under interpreter mode (aka bpf_jit_enable=0): WARNING: CPU: 3 PID: 4985 at kernel/bpf/helpers.c:40 ...... CPU: 3 PID: 4985 Comm: test_progs Not tainted 6.6.0+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...... RIP: 0010:bpf_map_lookup_elem+0x54/0x60 ...... Call Trace: <TASK> ? __warn+0xa5/0x240 ? bpf_map_lookup_elem+0x54/0x60 ? report_bug+0x1ba/0x1f0 ? handle_bug+0x40/0x80 ? exc_invalid_op+0x18/0x50 ? asm_exc_invalid_op+0x1b/0x20 ? __pfx_bpf_map_lookup_elem+0x10/0x10 ? rcu_lockdep_current_cpu_online+0x65/0xb0 ? rcu_is_watching+0x23/0x50 ? bpf_map_lookup_elem+0x54/0x60 ? __pfx_bpf_map_lookup_elem+0x10/0x10 ___bpf_prog_run+0x513/0x3b70 __bpf_prog_run32+0x9d/0xd0 ? __bpf_prog_enter_sleepable_recur+0xad/0x120 ? __bpf_prog_enter_sleepable_recur+0x3e/0x120 bpf_trampoline_6442580665+0x4d/0x1000 __x64_sys_getpgid+0x5/0x30 ? do_syscall_64+0x36/0xb0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 </TASK> Signed-off-by:
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- 04 Dec, 2023 2 commits
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Colin Ian King authored
There is a spelling mistake in an ASSERT_GT message. Fix it. Signed-off-by:
Colin Ian King <colin.i.king@gmail.com> Signed-off-by:
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Andrei Matei authored
One place where we were logging a register was only logging the variable part, not also the fixed part. Signed-off-by:
Andrei Matei <andreimatei1@gmail.com> Signed-off-by:
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- 02 Dec, 2023 19 commits
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Alexei Starovoitov authored
Andrii Nakryiko says: ==================== BPF verifier retval logic fixes This patch set fixes BPF verifier logic around validating and enforcing return values for BPF programs that have specific range of expected return values. Both sync and async callbacks have similar logic and are fixes as well. A few tests are added that would fail without the fixes in this patch set. Also, while at it, we update retval checking logic to use smin/smax range instead of tnum, avoiding future potential issues if expected range cannot be represented precisely by tnum (e.g., [0, 2] is not representable by tnum and is treated as [0, 3]). There is a little bit of refactoring to unify async callback and program exit logic to avoid duplication of checks as much as possible. v4->v5: - fix timer_bad_ret test on no-alu32 flavor (CI); v3->v4: - add back bpf_func_state rearrangement patch; - simplified patch #4 as suggested (Shung-Hsi); v2->v3: - more carefullly switch from umin/umax to smin/smax; v1->v2: - drop tnum from retval checks (Eduard); - use smin/smax instead of umin/umax (Alexei). ==================== Link: https://lore.kernel.org/r/20231202175705.885270-1-andrii@kernel.orgSigned-off-by:
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Andrii Nakryiko authored
Emit tnum representation as just a constant if all bits are known. Use decimal-vs-hex logic to determine exact format of emitted constant value, just like it's done for register range values. For that move tnum_strn() to kernel/bpf/log.c to reuse decimal-vs-hex determination logic and constants. Acked-by:
Shung-Hsi Yu <shung-hsi.yu@suse.com> Signed-off-by:
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Andrii Nakryiko authored
Add one more subtest to global_func15 selftest to validate that verifier properly marks r0 as precise and avoids erroneous state pruning of the branch that has return value outside of expected [0, 1] value. Acked-by:
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Andrii Nakryiko authored
Adjust timer/timer_ret_1 test to validate more carefully verifier logic of enforcing async callback return value. This test will pass only if return result is marked precise and read. Acked-by:
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Andrii Nakryiko authored
Given we enforce a valid range for program and async callback return value, we must mark R0 as precise to avoid incorrect state pruning. Fixes: b5dc0163 ("bpf: precise scalar_value tracking") Acked-by:
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Andrii Nakryiko authored
Use common logic to verify program return values and async callback return values. This allows to avoid duplication of any extra steps necessary, like precision marking, which will be added in the next patch. Acked-by:
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Andrii Nakryiko authored
Similarly to subprog/callback logic, enforce return value of BPF program using more precise smin/smax range. We need to adjust a bunch of tests due to a changed format of an error message. Acked-by:
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Andrii Nakryiko authored
BPF verifier expects callback subprogs to return values from specified range (typically [0, 1]). This requires that r0 at exit is both precise (because we rely on specific value range) and is marked as read (otherwise state comparison will ignore such register as unimportant). Add a simple test that validates that all these conditions are enforced. Acked-by:
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Andrii Nakryiko authored
Instead of relying on potentially imprecise tnum representation of expected return value range for callbacks and subprogs, validate that smin/smax range satisfy exact expected range of return values. E.g., if callback would need to return [0, 2] range, tnum can't represent this precisely and instead will allow [0, 3] range. By checking smin/smax range, we can make sure that subprog/callback indeed returns only valid [0, 2] range. Acked-by:
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Andrii Nakryiko authored
Given verifier checks actual value, r0 has to be precise, so we need to propagate precision properly. r0 also has to be marked as read, otherwise subsequent state comparisons will ignore such register as unimportant and precision won't really help here. Fixes: 69c087ba ("bpf: Add bpf_for_each_map_elem() helper") Acked-by:
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Andrii Nakryiko authored
bpf_throw() is checking R1, so let's report R1 in the log. Acked-by:
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Andrii Nakryiko authored
It's a trivial rearrangement saving 8 bytes. We have 4 bytes of padding at the end which can be filled with another field without increasing struct bpf_func_state. copy_func_state() logic remains correct without any further changes. BEFORE ====== struct bpf_func_state { struct bpf_reg_state regs[11]; /* 0 1320 */ /* --- cacheline 20 boundary (1280 bytes) was 40 bytes ago --- */ int callsite; /* 1320 4 */ u32 frameno; /* 1324 4 */ u32 subprogno; /* 1328 4 */ u32 async_entry_cnt; /* 1332 4 */ bool in_callback_fn; /* 1336 1 */ /* XXX 7 bytes hole, try to pack */ /* --- cacheline 21 boundary (1344 bytes) --- */ struct tnum callback_ret_range; /* 1344 16 */ bool in_async_callback_fn; /* 1360 1 */ bool in_exception_callback_fn; /* 1361 1 */ /* XXX 2 bytes hole, try to pack */ int acquired_refs; /* 1364 4 */ struct bpf_reference_state * refs; /* 1368 8 */ int allocated_stack; /* 1376 4 */ /* XXX 4 bytes hole, try to pack */ struct bpf_stack_state * stack; /* 1384 8 */ /* size: 1392, cachelines: 22, members: 13 */ /* sum members: 1379, holes: 3, sum holes: 13 */ /* last cacheline: 48 bytes */ }; AFTER ===== struct bpf_func_state { struct bpf_reg_state regs[11]; /* 0 1320 */ /* --- cacheline 20 boundary (1280 bytes) was 40 bytes ago --- */ int callsite; /* 1320 4 */ u32 frameno; /* 1324 4 */ u32 subprogno; /* 1328 4 */ u32 async_entry_cnt; /* 1332 4 */ struct tnum callback_ret_range; /* 1336 16 */ /* --- cacheline 21 boundary (1344 bytes) was 8 bytes ago --- */ bool in_callback_fn; /* 1352 1 */ bool in_async_callback_fn; /* 1353 1 */ bool in_exception_callback_fn; /* 1354 1 */ /* XXX 1 byte hole, try to pack */ int acquired_refs; /* 1356 4 */ struct bpf_reference_state * refs; /* 1360 8 */ struct bpf_stack_state * stack; /* 1368 8 */ int allocated_stack; /* 1376 4 */ /* size: 1384, cachelines: 22, members: 13 */ /* sum members: 1379, holes: 1, sum holes: 1 */ /* padding: 4 */ /* last cacheline: 40 bytes */ }; Acked-by: -
Alexei Starovoitov authored
Song Liu says: ==================== bpf: File verification with LSM and fsverity Changes v14 => v15: 1. Fix selftest build without CONFIG_FS_VERITY. (Alexei) 2. Add Acked-by from KP. Changes v13 => v14: 1. Add "static" for bpf_fs_kfunc_set. 2. Add Acked-by from Christian Brauner. Changes v12 => v13: 1. Only keep 4/9 through 9/9 of v12, as the first 3 patches already applied; 2. Use new macro __bpf_kfunc_[start|end]_defs(). Changes v11 => v12: 1. Fix typo (data_ptr => sig_ptr) in bpf_get_file_xattr(). Changes v10 => v11: 1. Let __bpf_dynptr_data() return const void *. (Andrii) 2. Optimize code to reuse output from __bpf_dynptr_size(). (Andrii) 3. Add __diag_ignore_all("-Wmissing-declarations") for kfunc definition. 4. Fix an off indentation. (Andrii) Changes v9 => v10: 1. Remove WARN_ON_ONCE() from check_reg_const_str. (Alexei) Changes v8 => v9: 1. Fix test_progs kfunc_dynptr_param/dynptr_data_null. Changes v7 => v8: 1. Do not use bpf_dynptr_slice* in the kernel. Add __bpf_dynptr_data* and use them in ther kernel. (Andrii) Changes v6 => v7: 1. Change "__const_str" annotation to "__str". (Alexei, Andrii) 2. Add KF_TRUSTED_ARGS flag for both new kfuncs. (KP) 3. Only allow bpf_get_file_xattr() to read xattr with "user." prefix. 4. Add Acked-by from Eric Biggers. Changes v5 => v6: 1. Let fsverity_init_bpf() return void. (Eric Biggers) 2. Sort things in alphabetic orders. (Eric Biggers) Changes v4 => v5: 1. Revise commit logs. (Alexei) Changes v3 => v4: 1. Fix error reported by CI. 2. Update comments of bpf_dynptr_slice* that they may return error pointer. Changes v2 => v3: 1. Rebase and resolve conflicts. Changes v1 => v2: 1. Let bpf_get_file_xattr() use const string for arg "name". (Alexei) 2. Add recursion prevention with allowlist. (Alexei) 3. Let bpf_get_file_xattr() use __vfs_getxattr() to avoid recursion, as vfs_getxattr() calls into other LSM hooks. 4. Do not use dynptr->data directly, use helper insteadd. (Andrii) 5. Fixes with bpf_get_fsverity_digest. (Eric Biggers) 6. Add documentation. (Eric Biggers) 7. Fix some compile warnings. (kernel test robot) This set enables file verification with BPF LSM and fsverity. In this solution, fsverity is used to provide reliable and efficient hash of files; and BPF LSM is used to implement signature verification (against asymmetric keys), and to enforce access control. This solution can be used to implement access control in complicated cases. For example: only signed python binary and signed python script and access special files/devices/ports. Thanks, Song ==================== Link: https://lore.kernel.org/r/20231129234417.856536-1-song@kernel.orgSigned-off-by: -
Song Liu authored
This selftests shows a proof of concept method to use BPF LSM to enforce file signature. This test is added to verify_pkcs7_sig, so that some existing logic can be reused. This file signature method uses fsverity, which provides reliable and efficient hash (known as digest) of the file. The file digest is signed with asymmetic key, and the signature is stored in xattr. At the run time, BPF LSM reads file digest and the signature, and then checks them against the public key. Note that this solution does NOT require FS_VERITY_BUILTIN_SIGNATURES. fsverity is only used to provide file digest. The signature verification and access control is all implemented in BPF LSM. Signed-off-by:
Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20231129234417.856536-7-song@kernel.orgSigned-off-by:
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Song Liu authored
Add selftests for two new filesystem kfuncs: 1. bpf_get_file_xattr 2. bpf_get_fsverity_digest These tests simply make sure the two kfuncs work. Another selftest will be added to demonstrate how to use these kfuncs to verify file signature. CONFIG_FS_VERITY is added to selftests config. However, this is not sufficient to guarantee bpf_get_fsverity_digest works. This is because fsverity need to be enabled at file system level (for example, with tune2fs on ext4). If local file system doesn't have this feature enabled, just skip the test. Signed-off-by:
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Song Liu authored
Move CONFIG_VSOCKETS up, so the CONFIGs are in alphabetic order. Signed-off-by:
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Song Liu authored
Add a brief introduction for file system kfuncs: bpf_get_file_xattr() bpf_get_fsverity_digest() The documentation highlights the strategy to avoid recursions of these kfuncs. Signed-off-by:
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Song Liu authored
fsverity provides fast and reliable hash of files, namely fsverity_digest. The digest can be used by security solutions to verify file contents. Add new kfunc bpf_get_fsverity_digest() so that we can access fsverity from BPF LSM programs. This kfunc is added to fs/verity/measure.c because some data structure used in the function is private to fsverity (fs/verity/fsverity_private.h). To avoid recursion, bpf_get_fsverity_digest is only allowed in BPF LSM programs. Signed-off-by:
Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20231129234417.856536-3-song@kernel.orgSigned-off-by:
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Song Liu authored
It is common practice for security solutions to store tags/labels in xattrs. To implement similar functionalities in BPF LSM, add new kfunc bpf_get_file_xattr(). The first use case of bpf_get_file_xattr() is to implement file verifications with asymmetric keys. Specificially, security applications could use fsverity for file hashes and use xattr to store file signatures. (kfunc for fsverity hash will be added in a separate commit.) Currently, only xattrs with "user." prefix can be read with kfunc bpf_get_file_xattr(). As use cases evolve, we may add a dedicated prefix for bpf_get_file_xattr(). To avoid recursion, bpf_get_file_xattr can be only called from LSM hooks. Signed-off-by:
Christian Brauner <brauner@kernel.org> Acked-by:
KP Singh <kpsingh@kernel.org> Link: https://lore.kernel.org/r/20231129234417.856536-2-song@kernel.orgSigned-off-by:
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- 01 Dec, 2023 3 commits
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Jeroen van Ingen Schenau authored
xdp_synproxy_kern.c is a BPF program that generates SYN cookies on allowed TCP ports and sends SYNACKs to clients, accelerating synproxy iptables module. Fix the bitmask operation when checking the status of an existing conntrack entry within tcp_lookup() function. Do not AND with the bit position number, but with the bitmask value to check whether the entry found has the IPS_CONFIRMED flag set. Fixes: fb5cd0ce ("selftests/bpf: Add selftests for raw syncookie helpers") Signed-off-by:
Jeroen van Ingen Schenau <jeroen.vaningenschenau@novoserve.com> Signed-off-by:
Minh Le Hoang <minh.lehoang@novoserve.com> Link: https://lore.kernel.org/xdp-newbies/CAAi1gX7owA+Tcxq-titC-h-KPM7Ri-6ZhTNMhrnPq5gmYYwKow@mail.gmail.com/T/#u Link: https://lore.kernel.org/bpf/20231130120353.3084-1-jeroen.vaningenschenau@novoserve.com
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Shinas Rasheed authored
Set backpressure watermark for hardware RX queues. Backpressure gets triggered when the available buffers of a hardware RX queue falls below the set watermark. This backpressure will propagate to packet processing pipeline in the OCTEON card, so that the host receives fewer packets and prevents packet dropping at host. Signed-off-by:
Shinas Rasheed <srasheed@marvell.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Dan Carpenter authored
Set the error code if octep_ctrl_net_get_mtu() fails. Currently the code returns success. Fixes: 0a5f8534 ("octeon_ep: get max rx packet length from firmware") Signed-off-by:
Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by:
Sathesh B Edara <sedara@marvell.com> Signed-off-by:
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