linux/lib/test_bpf.c, branch v4.1

test: bpf: expand DIV_KX to DIV_MOD_KX

2014-12-09T01:23:22Z

Expand DIV_KX to use BPF_MOD operation in the DIV_KX bpf 'classic' test. CC: Alexei Starovoitov Signed-off-by: Denis Kirjanov Signed-off-by: David S. Miller

test: bpf: add a testcase reduced from nmap

2014-10-30T19:44:37Z

nmap generates classic BPF programs to filter ARP packets with given target MAC which triggered a bug in eBPF x64 JIT. The bug was fixed in commit e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT compiler") This patch is adding a testcase in eBPF instructions (those that were generated by classic->eBPF converter) to be processed by JIT. The test is primarily targeting JIT compiler. Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller

net: bpf: fix compiler warnings in test_bpf

2014-09-22T20:21:30Z

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 Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller

net: filter: add "load 64-bit immediate" eBPF instruction

2014-09-09T17:26:47Z

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 Signed-off-by: David S. Miller

net: bpf: make eBPF interpreter images read-only

2014-09-05T19:02:48Z

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 Signed-off-by: Daniel Borkmann Signed-off-by: Hannes Frederic Sowa Cc: Alexei Starovoitov Cc: Kees Cook Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

bpf: x86: add missing 'shift by register' instructions to x64 eBPF JIT

2014-08-26T00:33:56Z

'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 Signed-off-by: Alexei Starovoitov Fixes: 622582786c9e ("net: filter: x86: internal BPF JIT") Signed-off-by: David S. Miller

net: filter: split 'struct sk_filter' into socket and bpf parts

2014-08-02T22:03:58Z

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 Signed-off-by: David S. Miller

net: filter: rename 'struct sock_filter_int' into 'struct bpf_insn'

2014-07-25T06:27:17Z

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 Signed-off-by: David S. Miller

net: filter: fix nlattr and nlattr_nest BPF tests

2014-06-11T07:13:16Z

- 'struct nlattr' must be 2 byte aligned - provide big-endian input data for nlattr/nlattr_nest tests Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller

net: filter: fix length calculation in BPF testsuite

2014-06-02T23:32:43Z

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 Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller