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2014-09-22net: bpf: fix compiler warnings in test_bpfAlexei Starovoitov
old gcc 4.2 used by avr32 architecture produces warnings: lib/test_bpf.c:1741: warning: integer constant is too large for 'long' type lib/test_bpf.c:1741: warning: integer constant is too large for 'long' type lib/test_bpf.c: In function '__run_one': lib/test_bpf.c:1897: warning: 'ret' may be used uninitialized in this function silence these warnings. Fixes: 02ab695bb37e ("net: filter: add "load 64-bit immediate" eBPF instruction") Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-09net: filter: add "load 64-bit immediate" eBPF instructionAlexei Starovoitov
add BPF_LD_IMM64 instruction to load 64-bit immediate value into a register. All previous instructions were 8-byte. This is first 16-byte instruction. Two consecutive 'struct bpf_insn' blocks are interpreted as single instruction: insn[0].code = BPF_LD | BPF_DW | BPF_IMM insn[0].dst_reg = destination register insn[0].imm = lower 32-bit insn[1].code = 0 insn[1].imm = upper 32-bit All unused fields must be zero. Classic BPF has similar instruction: BPF_LD | BPF_W | BPF_IMM which loads 32-bit immediate value into a register. x64 JITs it as single 'movabsq %rax, imm64' arm64 may JIT as sequence of four 'movk x0, #imm16, lsl #shift' insn Note that old eBPF programs are binary compatible with new interpreter. It helps eBPF programs load 64-bit constant into a register with one instruction instead of using two registers and 4 instructions: BPF_MOV32_IMM(R1, imm32) BPF_ALU64_IMM(BPF_LSH, R1, 32) BPF_MOV32_IMM(R2, imm32) BPF_ALU64_REG(BPF_OR, R1, R2) User space generated programs will use this instruction to load constants only. To tell kernel that user space needs a pointer the _pseudo_ variant of this instruction may be added later, which will use extra bits of encoding to indicate what type of pointer user space is asking kernel to provide. For example 'off' or 'src_reg' fields can be used for such purpose. src_reg = 1 could mean that user space is asking kernel to validate and load in-kernel map pointer. src_reg = 2 could mean that user space needs readonly data section pointer src_reg = 3 could mean that user space needs a pointer to per-cpu local data All such future pseudo instructions will not be carrying the actual pointer as part of the instruction, but rather will be treated as a request to kernel to provide one. The kernel will verify the request_for_a_pointer, then will drop _pseudo_ marking and will store actual internal pointer inside the instruction, so the end result is the interpreter and JITs never see pseudo BPF_LD_IMM64 insns and only operate on generic BPF_LD_IMM64 that loads 64-bit immediate into a register. User space never operates on direct pointers and verifier can easily recognize request_for_pointer vs other instructions. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-05net: bpf: make eBPF interpreter images read-onlyDaniel Borkmann
With eBPF getting more extended and exposure to user space is on it's way, hardening the memory range the interpreter uses to steer its command flow seems appropriate. This patch moves the to be interpreted bytecode to read-only pages. In case we execute a corrupted BPF interpreter image for some reason e.g. caused by an attacker which got past a verifier stage, it would not only provide arbitrary read/write memory access but arbitrary function calls as well. After setting up the BPF interpreter image, its contents do not change until destruction time, thus we can setup the image on immutable made pages in order to mitigate modifications to that code. The idea is derived from commit 314beb9bcabf ("x86: bpf_jit_comp: secure bpf jit against spraying attacks"). This is possible because bpf_prog is not part of sk_filter anymore. After setup bpf_prog cannot be altered during its life-time. This prevents any modifications to the entire bpf_prog structure (incl. function/JIT image pointer). Every eBPF program (including classic BPF that are migrated) have to call bpf_prog_select_runtime() to select either interpreter or a JIT image as a last setup step, and they all are being freed via bpf_prog_free(), including non-JIT. Therefore, we can easily integrate this into the eBPF life-time, plus since we directly allocate a bpf_prog, we have no performance penalty. Tested with seccomp and test_bpf testsuite in JIT/non-JIT mode and manual inspection of kernel_page_tables. Brad Spengler proposed the same idea via Twitter during development of this patch. Joint work with Hannes Frederic Sowa. Suggested-by: Brad Spengler <spender@grsecurity.net> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Kees Cook <keescook@chromium.org> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-25bpf: x86: add missing 'shift by register' instructions to x64 eBPF JITAlexei Starovoitov
'shift by register' operations are supported by eBPF interpreter, but were accidently left out of x64 JIT compiler. Fix it and add a testcase. Reported-by: Brendan Gregg <brendan.d.gregg@gmail.com> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Fixes: 622582786c9e ("net: filter: x86: internal BPF JIT") Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-02net: filter: split 'struct sk_filter' into socket and bpf partsAlexei Starovoitov
clean up names related to socket filtering and bpf in the following way: - everything that deals with sockets keeps 'sk_*' prefix - everything that is pure BPF is changed to 'bpf_*' prefix split 'struct sk_filter' into struct sk_filter { atomic_t refcnt; struct rcu_head rcu; struct bpf_prog *prog; }; and struct bpf_prog { u32 jited:1, len:31; struct sock_fprog_kern *orig_prog; unsigned int (*bpf_func)(const struct sk_buff *skb, const struct bpf_insn *filter); union { struct sock_filter insns[0]; struct bpf_insn insnsi[0]; struct work_struct work; }; }; so that 'struct bpf_prog' can be used independent of sockets and cleans up 'unattached' bpf use cases split SK_RUN_FILTER macro into: SK_RUN_FILTER to be used with 'struct sk_filter *' and BPF_PROG_RUN to be used with 'struct bpf_prog *' __sk_filter_release(struct sk_filter *) gains __bpf_prog_release(struct bpf_prog *) helper function also perform related renames for the functions that work with 'struct bpf_prog *', since they're on the same lines: sk_filter_size -> bpf_prog_size sk_filter_select_runtime -> bpf_prog_select_runtime sk_filter_free -> bpf_prog_free sk_unattached_filter_create -> bpf_prog_create sk_unattached_filter_destroy -> bpf_prog_destroy sk_store_orig_filter -> bpf_prog_store_orig_filter sk_release_orig_filter -> bpf_release_orig_filter __sk_migrate_filter -> bpf_migrate_filter __sk_prepare_filter -> bpf_prepare_filter API for attaching classic BPF to a socket stays the same: sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *) and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program which is used by sockets, tun, af_packet API for 'unattached' BPF programs becomes: bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *) and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-24net: filter: rename 'struct sock_filter_int' into 'struct bpf_insn'Alexei Starovoitov
eBPF is used by socket filtering, seccomp and soon by tracing and exposed to userspace, therefore 'sock_filter_int' name is not accurate. Rename it to 'bpf_insn' Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-11net: filter: fix nlattr and nlattr_nest BPF testsAlexei Starovoitov
- 'struct nlattr' must be 2 byte aligned - provide big-endian input data for nlattr/nlattr_nest tests Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-02net: filter: fix length calculation in BPF testsuiteChema Gonzalez
The current probe_filter_length() (the function that calculates the length of a test BPF filter) behavior is to declare the end of the filter as soon as it finds {0, *, *, 0}. This is actually a valid insn ("ld #0"), so any filter with includes "BPF_STMT(BPF_LD | BPF_IMM, 0)" fails (its length is cut short). We are changing probe_filter_length() so as to start from the end, and declare the end of the filter as the first instruction which is not {0, *, *, 0}. This solution produces a simpler patch than the alternative of using an explicit end-of-filter mark. It is technically incorrect if your filter ends up with "ld #0", but that should not happen anyway. We also add a new test (LD_IMM_0) that includes ld #0 (does not work without this patch). Signed-off-by: Chema Gonzalez <chema@google.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-01net: filter: add test for loading SKF_AD_OFF limitsDaniel Borkmann
This check tests that overloading BPF_LD | BPF_ABS with an always invalid BPF extension, that is SKF_AD_MAX, fails to make sure classic BPF behaviour is correct in filter checker. Also, we add a test for loading at packet offset SKF_AD_OFF-1 which should pass the filter, but later on fail during runtime. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-01net: filter: add slot overlapping test with fully filled M[]Daniel Borkmann
Also add a test for the scratch memory store that first fills all slots and then sucessively reads all of them back adding up to A, and eventually returning A. This and the previous M[] test with alternating fill/spill will detect possible JIT errors on M[]. Suggested-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-30net: filter: use block statements in tcpdump testsDaniel Borkmann
This patch converts raw opcodes for tcpdump tests into BPF_STMT()/BPF_JUMP() combinations, which brings it into conformity with the rest of the patches and it also makes life easier to grasp what's going on in these particular test cases when they ever fail. Also arrange payload from the jump+holes test in a way as we have with other packet payloads in the test suite. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-30net: filter: test fill/spill of all M[] regsDaniel Borkmann
This test for classic BPF probes stores and load combination via X on all 16 registers of the scratch memory store. It initially loads integer 100 and passes this value around to each register while incrementing it every time, thus we expect to have 116 as a result. Might be useful for JIT testing. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-23net: filter: add test case for jump with holes and ret x variantsDaniel Borkmann
This patch adds three more test cases: 1) long jumps with holes of unreachable code 2) ret x 3) ldx + ret x All three tests are for classical BPF and to make sure that any changes will not break some exotic behaviour that exists probably since decades. The last two tests are expected to fail by the BPF checker already, as in classic BPF only K or A are allowed to be returned. Thus, there are now 52 test cases for BPF. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-23net: filter: improve test case frameworkDaniel Borkmann
This patch simplifies and refactors the test case code a bit and also adds a summary of all test that passed or failed in the kernel log, so that it's easier to spot if something has failed. Future work could further extend the test framework to also support different input 'stimuli' i.e. related structures to seccomp. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-23net: filter: let unattached filters use sock_fprog_kernDaniel Borkmann
The sk_unattached_filter_create() API is used by BPF filters that are not directly attached or related to sockets, and are used in team, ptp, xt_bpf, cls_bpf, etc. As such all users do their own internal managment of obtaining filter blocks and thus already have them in kernel memory and set up before calling into sk_unattached_filter_create(). As a result, due to __user annotation in sock_fprog, sparse triggers false positives (incorrect type in assignment [different address space]) when filters are set up before passing them to sk_unattached_filter_create(). Therefore, let sk_unattached_filter_create() API use sock_fprog_kern to overcome this issue. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-23lib/test_bpf.c: don't use gcc union shortcutAndrew Morton
Older gcc's (mine is gcc-4.4.4) make a mess of this. lib/test_bpf.c:74: error: unknown field 'insns' specified in initializer lib/test_bpf.c:75: warning: missing braces around initializer lib/test_bpf.c:75: warning: (near initialization for 'tests[0].<anonymous>.insns[0]') lib/test_bpf.c:76: error: extra brace group at end of initializer lib/test_bpf.c:76: error: (near initialization for 'tests[0].<anonymous>') lib/test_bpf.c:76: warning: excess elements in union initializer lib/test_bpf.c:76: warning: (near initialization for 'tests[0].<anonymous>') lib/test_bpf.c:77: error: extra brace group at end of initializer Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-21net: filter: cleanup invocation of internal BPFAlexei Starovoitov
Kernel API for classic BPF socket filters is: sk_unattached_filter_create() - validate classic BPF, convert, JIT SK_RUN_FILTER() - run it sk_unattached_filter_destroy() - destroy socket filter Cleanup internal BPF kernel API as following: sk_filter_select_runtime() - final step of internal BPF creation. Try to JIT internal BPF program, if JIT is not available select interpreter SK_RUN_FILTER() - run it sk_filter_free() - free internal BPF program Disallow direct calls to BPF interpreter. Execution of the BPF program should be done with SK_RUN_FILTER() macro. Example of internal BPF create, run, destroy: struct sk_filter *fp; fp = kzalloc(sk_filter_size(prog_len), GFP_KERNEL); memcpy(fp->insni, prog, prog_len * sizeof(fp->insni[0])); fp->len = prog_len; sk_filter_select_runtime(fp); SK_RUN_FILTER(fp, ctx); sk_filter_free(fp); Sockets, seccomp, testsuite, tracing are using different ways to populate sk_filter, so first steps of program creation are not common. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-12net: filter: additional BPF testsAlexei Starovoitov
All tests should pass with and without JIT. Example output: test_bpf: #0 TAX 35 16 16 PASS test_bpf: #1 TXA 7 7 7 PASS test_bpf: #2 ADD_SUB_MUL_K 10 PASS test_bpf: #3 DIV_KX 33 PASS test_bpf: #4 AND_OR_LSH_K 10 10 PASS test_bpf: #5 LD_IND 8 8 8 PASS test_bpf: #6 LD_ABS 8 8 8 PASS test_bpf: #7 LD_ABS_LL 13 14 PASS test_bpf: #8 LD_IND_LL 12 12 12 PASS test_bpf: #9 LD_ABS_NET 10 12 PASS test_bpf: #10 LD_IND_NET 11 12 12 PASS ... Numbers are times in nsec per filter for given input data. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-12net: filter: BPF testsuiteAlexei Starovoitov
The testsuite covers classic and internal BPF instructions. It is particularly useful for JIT compiler developers. Adds to "net" selftest target. The testsuite can be used as a set of micro-benchmarks. It measures execution time of each BPF program in nsec. This patch adds core framework. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>