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* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds2015-01-271-8/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking fixes from David Miller: 1) Don't OOPS on socket AIO, from Christoph Hellwig. 2) Scheduled scans should be aborted upon RFKILL, from Emmanuel Grumbach. 3) Fix sleep in atomic context in kvaser_usb, from Ahmed S Darwish. 4) Fix RCU locking across copy_to_user() in bpf code, from Alexei Starovoitov. 5) Lots of crash, memory leak, short TX packet et al bug fixes in sh_eth from Ben Hutchings. 6) Fix memory corruption in SCTP wrt. INIT collitions, from Daniel Borkmann. 7) Fix return value logic for poll handlers in netxen, enic, and bnx2x. From Eric Dumazet and Govindarajulu Varadarajan. 8) Header length calculation fix in mac80211 from Fred Chou. 9) mv643xx_eth doesn't handle highmem correctly in non-TSO code paths. From Ezequiel Garcia. 10) udp_diag has bogus logic in it's hash chain skipping, copy same fix tcp diag used. From Herbert Xu. 11) amd-xgbe programs wrong rx flow control register, from Thomas Lendacky. 12) Fix race leading to use after free in ping receive path, from Subash Abhinov Kasiviswanathan. 13) Cache redirect routes otherwise we can get a heavy backlog of rcu jobs liberating DST_NOCACHE entries. From Hannes Frederic Sowa. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (48 commits) net: don't OOPS on socket aio stmmac: prevent probe drivers to crash kernel bnx2x: fix napi poll return value for repoll ipv6: replacing a rt6_info needs to purge possible propagated rt6_infos too sh_eth: Fix DMA-API usage for RX buffers sh_eth: Check for DMA mapping errors on transmit sh_eth: Ensure DMA engines are stopped before freeing buffers sh_eth: Remove RX overflow log messages ping: Fix race in free in receive path udp_diag: Fix socket skipping within chain can: kvaser_usb: Fix state handling upon BUS_ERROR events can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT can: kvaser_usb: Send correct context to URB completion can: kvaser_usb: Do not sleep in atomic context ipv4: try to cache dst_entries which would cause a redirect samples: bpf: relax test_maps check bpf: rcu lock must not be held when calling copy_to_user() net: sctp: fix slab corruption from use after free on INIT collisions net: mv643xx_eth: Fix highmem support in non-TSO egress path sh_eth: Fix serialisation of interrupt disable with interrupt & NAPI handlers ...
| * bpf: rcu lock must not be held when calling copy_to_user()Alexei Starovoitov2015-01-261-8/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BUG: sleeping function called from invalid context at mm/memory.c:3732 in_atomic(): 0, irqs_disabled(): 0, pid: 671, name: test_maps 1 lock held by test_maps/671: #0: (rcu_read_lock){......}, at: [<0000000000264190>] map_lookup_elem+0xe8/0x260 Call Trace: ([<0000000000115b7e>] show_trace+0x12e/0x150) [<0000000000115c40>] show_stack+0xa0/0x100 [<00000000009b163c>] dump_stack+0x74/0xc8 [<000000000017424a>] ___might_sleep+0x23a/0x248 [<00000000002b58e8>] might_fault+0x70/0xe8 [<0000000000264230>] map_lookup_elem+0x188/0x260 [<0000000000264716>] SyS_bpf+0x20e/0x840 Fix it by allocating temporary buffer to store map element value. Fixes: db20fd2b0108 ("bpf: add lookup/update/delete/iterate methods to BPF maps") Reported-by: Michael Holzheu <holzheu@linux.vnet.ibm.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>
* | module: remove mod arg from module_free, rename module_memfree().Rusty Russell2015-01-201-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nothing needs the module pointer any more, and the next patch will call it from RCU, where the module itself might no longer exist. Removing the arg is the safest approach. This just codifies the use of the module_alloc/module_free pattern which ftrace and bpf use. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Ley Foon Tan <lftan@altera.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: x86@kernel.org Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: linux-cris-kernel@axis.com Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: nios2-dev@lists.rocketboards.org Cc: linuxppc-dev@lists.ozlabs.org Cc: sparclinux@vger.kernel.org Cc: netdev@vger.kernel.org
* bpf: verifier: add checks for BPF_ABS | BPF_IND instructionsAlexei Starovoitov2014-12-051-2/+68
| | | | | | | | | | | | | introduce program type BPF_PROG_TYPE_SOCKET_FILTER that is used for attaching programs to sockets where ctx == skb. add verifier checks for ABS/IND instructions which can only be seen in socket filters, therefore the check: if (env->prog->aux->prog_type != BPF_PROG_TYPE_SOCKET_FILTER) verbose("BPF_LD_ABS|IND instructions are only allowed in socket filters\n"); Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: fix arraymap NULL deref and missing overflow and zero size checksAlexei Starovoitov2014-11-192-6/+16
| | | | | | | | | | | | | | | | | | | | | | - fix NULL pointer dereference: kernel/bpf/arraymap.c:41 array_map_alloc() error: potential null dereference 'array'. (kzalloc returns null) kernel/bpf/arraymap.c:41 array_map_alloc() error: we previously assumed 'array' could be null (see line 40) - integer overflow check was missing in arraymap (hashmap checks for overflow via kmalloc_array()) - arraymap can round_up(value_size, 8) to zero. check was missing. - hashmap was missing zero size check as well, since roundup_pow_of_two() can truncate into zero - found a typo in the arraymap comment and unnecessary empty line Fix all of these issues and make both overflow checks explicit U32 in size. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: remove test map scaffolding and user proper typesAlexei Starovoitov2014-11-181-47/+9
| | | | | | | | proper types and function helpers are ready. Use them in verifier testsuite. Remove temporary stubs Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: allow eBPF programs to use mapsAlexei Starovoitov2014-11-182-1/+90
| | | | | | | | expose bpf_map_lookup_elem(), bpf_map_update_elem(), bpf_map_delete_elem() map accessors to eBPF programs Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: fix BPF_MAP_LOOKUP_ELEM command return codeAlexei Starovoitov2014-11-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fix errno of BPF_MAP_LOOKUP_ELEM command as bpf manpage described it in commit b4fc1a460f30("Merge branch 'bpf-next'"): ----- BPF_MAP_LOOKUP_ELEM int bpf_lookup_elem(int fd, void *key, void *value) { union bpf_attr attr = { .map_fd = fd, .key = ptr_to_u64(key), .value = ptr_to_u64(value), }; return bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr)); } bpf() syscall looks up an element with given key in a map fd. If element is found it returns zero and stores element's value into value. If element is not found it returns -1 and sets errno to ENOENT. and further down in manpage: ENOENT For BPF_MAP_LOOKUP_ELEM or BPF_MAP_DELETE_ELEM, indicates that element with given key was not found. ----- In general all BPF commands return ENOENT when map element is not found (including BPF_MAP_GET_NEXT_KEY and BPF_MAP_UPDATE_ELEM with flags == BPF_MAP_UPDATE_ONLY) Subsequent patch adds a testsuite to check return values for all of these combinations. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: add array type of eBPF mapsAlexei Starovoitov2014-11-182-1/+152
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | add new map type BPF_MAP_TYPE_ARRAY and its implementation - optimized for fastest possible lookup() . in the future verifier/JIT may recognize lookup() with constant key and optimize it into constant pointer. Can optimize non-constant key into direct pointer arithmetic as well, since pointers and value_size are constant for the life of the eBPF program. In other words array_map_lookup_elem() may be 'inlined' by verifier/JIT while preserving concurrent access to this map from user space - two main use cases for array type: . 'global' eBPF variables: array of 1 element with key=0 and value is a collection of 'global' variables which programs can use to keep the state between events . aggregation of tracing events into fixed set of buckets - all array elements pre-allocated and zero initialized at init time - key as an index in array and can only be 4 byte - map_delete_elem() returns EINVAL, since elements cannot be deleted - map_update_elem() replaces elements in an non-atomic way (for atomic updates hashtable type should be used instead) Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: add hashtable type of eBPF mapsAlexei Starovoitov2014-11-182-1/+363
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | add new map type BPF_MAP_TYPE_HASH and its implementation - maps are created/destroyed by userspace. Both userspace and eBPF programs can lookup/update/delete elements from the map - eBPF programs can be called in_irq(), so use spin_lock_irqsave() mechanism for concurrent updates - key/value are opaque range of bytes (aligned to 8 bytes) - user space provides 3 configuration attributes via BPF syscall: key_size, value_size, max_entries - map takes care of allocating/freeing key/value pairs - map_update_elem() must fail to insert new element when max_entries limit is reached to make sure that eBPF programs cannot exhaust memory - map_update_elem() replaces elements in an atomic way - optimized for speed of lookup() which can be called multiple times from eBPF program which itself is triggered by high volume of events . in the future JIT compiler may recognize lookup() call and optimize it further, since key_size is constant for life of eBPF program Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: add 'flags' attribute to BPF_MAP_UPDATE_ELEM commandAlexei Starovoitov2014-11-181-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | the current meaning of BPF_MAP_UPDATE_ELEM syscall command is: either update existing map element or create a new one. Initially the plan was to add a new command to handle the case of 'create new element if it didn't exist', but 'flags' style looks cleaner and overall diff is much smaller (more code reused), so add 'flags' attribute to BPF_MAP_UPDATE_ELEM command with the following meaning: #define BPF_ANY 0 /* create new element or update existing */ #define BPF_NOEXIST 1 /* create new element if it didn't exist */ #define BPF_EXIST 2 /* update existing element */ bpf_update_elem(fd, key, value, BPF_NOEXIST) call can fail with EEXIST if element already exists. bpf_update_elem(fd, key, value, BPF_EXIST) can fail with ENOENT if element doesn't exist. Userspace will call it as: int bpf_update_elem(int fd, void *key, void *value, __u64 flags) { union bpf_attr attr = { .map_fd = fd, .key = ptr_to_u64(key), .value = ptr_to_u64(value), .flags = flags; }; return bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr)); } First two bits of 'flags' are used to encode style of bpf_update_elem() command. Bits 2-63 are reserved for future use. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2014-11-012-3/+12
|\ | | | | | | | | | | | | | | | | Conflicts: drivers/net/phy/marvell.c Simple overlapping changes in drivers/net/phy/marvell.c Signed-off-by: David S. Miller <davem@davemloft.net>
| * bpf: split eBPF out of NETAlexei Starovoitov2014-10-272-3/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | introduce two configs: - hidden CONFIG_BPF to select eBPF interpreter that classic socket filters depend on - visible CONFIG_BPF_SYSCALL (default off) that tracing and sockets can use that solves several problems: - tracing and others that wish to use eBPF don't need to depend on NET. They can use BPF_SYSCALL to allow loading from userspace or select BPF to use it directly from kernel in NET-less configs. - in 3.18 programs cannot be attached to events yet, so don't force it on - when the rest of eBPF infra is there in 3.19+, it's still useful to switch it off to minimize kernel size bloat-o-meter on x64 shows: add/remove: 0/60 grow/shrink: 0/2 up/down: 0/-15601 (-15601) tested with many different config combinations. Hopefully didn't miss anything. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | bpf: reduce verifier memory consumptionAlexei Starovoitov2014-10-301-44/+57
|/ | | | | | | | | | | | | | | | | | | | | | verifier keeps track of register state spilled to stack. registers are 8-byte wide and always aligned, so instead of tracking them in every byte-sized stack slot, use MAX_BPF_STACK / 8 array to track spilled register state. Though verifier runs in user context and its state freed immediately after verification, it makes sense to reduce its memory usage. This optimization reduces sizeof(struct verifier_state) from 12464 to 1712 on 64-bit and from 6232 to 1112 on 32-bit. Note, this patch doesn't change existing limits, which are there to bound time and memory during verification: 4k total number of insns in a program, 1k number of jumps (states to visit) and 32k number of processed insn (since an insn may be visited multiple times). Theoretical worst case memory during verification is 1712 * 1k = 17Mbyte. Out-of-memory situation triggers cleanup and rejects the program. Suggested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: fix bug in eBPF verifierAlexei Starovoitov2014-10-211-1/+2
| | | | | | | | | | | | while comparing for verifier state equivalency the comparison was missing a check for uninitialized register. Make sure it does so and add a testcase. Fixes: f1bca824dabb ("bpf: add search pruning optimization to verifier") Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: add search pruning optimization to verifierAlexei Starovoitov2014-10-011-0/+146
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | consider C program represented in eBPF: int filter(int arg) { int a, b, c, *ptr; if (arg == 1) ptr = &a; else if (arg == 2) ptr = &b; else ptr = &c; *ptr = 0; return 0; } eBPF verifier has to follow all possible paths through the program to recognize that '*ptr = 0' instruction would be safe to execute in all situations. It's doing it by picking a path towards the end and observes changes to registers and stack at every insn until it reaches bpf_exit. Then it comes back to one of the previous branches and goes towards the end again with potentially different values in registers. When program has a lot of branches, the number of possible combinations of branches is huge, so verifer has a hard limit of walking no more than 32k instructions. This limit can be reached and complex (but valid) programs could be rejected. Therefore it's important to recognize equivalent verifier states to prune this depth first search. Basic idea can be illustrated by the program (where .. are some eBPF insns): 1: .. 2: if (rX == rY) goto 4 3: .. 4: .. 5: .. 6: bpf_exit In the first pass towards bpf_exit the verifier will walk insns: 1, 2, 3, 4, 5, 6 Since insn#2 is a branch the verifier will remember its state in verifier stack to come back to it later. Since insn#4 is marked as 'branch target', the verifier will remember its state in explored_states[4] linked list. Once it reaches insn#6 successfully it will pop the state recorded at insn#2 and will continue. Without search pruning optimization verifier would have to walk 4, 5, 6 again, effectively simulating execution of insns 1, 2, 4, 5, 6 With search pruning it will check whether state at #4 after jumping from #2 is equivalent to one recorded in explored_states[4] during first pass. If there is an equivalent state, verifier can prune the search at #4 and declare this path to be safe as well. In other words two states at #4 are equivalent if execution of 1, 2, 3, 4 insns and 1, 2, 4 insns produces equivalent registers and stack. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: mini eBPF library, test stubs and verifier testsuiteAlexei Starovoitov2014-09-262-0/+120
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1. the library includes a trivial set of BPF syscall wrappers: int bpf_create_map(int key_size, int value_size, int max_entries); int bpf_update_elem(int fd, void *key, void *value); int bpf_lookup_elem(int fd, void *key, void *value); int bpf_delete_elem(int fd, void *key); int bpf_get_next_key(int fd, void *key, void *next_key); int bpf_prog_load(enum bpf_prog_type prog_type, const struct sock_filter_int *insns, int insn_len, const char *license); bpf_prog_load() stores verifier log into global bpf_log_buf[] array and BPF_*() macros to build instructions 2. test stubs configure eBPF infra with 'unspec' map and program types. These are fake types used by user space testsuite only. 3. verifier tests valid and invalid programs and expects predefined error log messages from kernel. 40 tests so far. $ sudo ./test_verifier #0 add+sub+mul OK #1 unreachable OK #2 unreachable2 OK #3 out of range jump OK #4 out of range jump2 OK #5 test1 ld_imm64 OK ... Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: verifier (add verifier core)Alexei Starovoitov2014-09-261-1/+1074
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds verifier core which simulates execution of every insn and records the state of registers and program stack. Every branch instruction seen during simulation is pushed into state stack. When verifier reaches BPF_EXIT, it pops the state from the stack and continues until it reaches BPF_EXIT again. For program: 1: bpf_mov r1, xxx 2: if (r1 == 0) goto 5 3: bpf_mov r0, 1 4: goto 6 5: bpf_mov r0, 2 6: bpf_exit The verifier will walk insns: 1, 2, 3, 4, 6 then it will pop the state recorded at insn#2 and will continue: 5, 6 This way it walks all possible paths through the program and checks all possible values of registers. While doing so, it checks for: - invalid instructions - uninitialized register access - uninitialized stack access - misaligned stack access - out of range stack access - invalid calling convention - instruction encoding is not using reserved fields Kernel subsystem configures the verifier with two callbacks: - bool (*is_valid_access)(int off, int size, enum bpf_access_type type); that provides information to the verifer which fields of 'ctx' are accessible (remember 'ctx' is the first argument to eBPF program) - const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id); returns argument constraints of kernel helper functions that eBPF program may call, so that verifier can checks that R1-R5 types match the prototype More details in Documentation/networking/filter.txt and in kernel/bpf/verifier.c Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: verifier (add branch/goto checks)Alexei Starovoitov2014-09-261-0/+189
| | | | | | | | | | | | | check that control flow graph of eBPF program is a directed acyclic graph check_cfg() does: - detect loops - detect unreachable instructions - check that program terminates with BPF_EXIT insn - check that all branches are within program boundary Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: handle pseudo BPF_LD_IMM64 insnAlexei Starovoitov2014-09-261-0/+147
| | | | | | | | | | | | | | eBPF programs passed from userspace are using pseudo BPF_LD_IMM64 instructions to refer to process-local map_fd. Scan the program for such instructions and if FDs are valid, convert them to 'struct bpf_map' pointers which will be used by verifier to check access to maps in bpf_map_lookup/update() calls. If program passes verifier, convert pseudo BPF_LD_IMM64 into generic by dropping BPF_PSEUDO_MAP_FD flag. Note that eBPF interpreter is generic and knows nothing about pseudo insns. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: verifier (add ability to receive verification log)Alexei Starovoitov2014-09-262-1/+236
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | add optional attributes for BPF_PROG_LOAD syscall: union bpf_attr { struct { ... __u32 log_level; /* verbosity level of eBPF verifier */ __u32 log_size; /* size of user buffer */ __aligned_u64 log_buf; /* user supplied 'char *buffer' */ }; }; when log_level > 0 the verifier will return its verification log in the user supplied buffer 'log_buf' which can be used by program author to analyze why verifier rejected given program. 'Understanding eBPF verifier messages' section of Documentation/networking/filter.txt provides several examples of these messages, like the program: BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), BPF_LD_MAP_FD(BPF_REG_1, 0), BPF_CALL_FUNC(BPF_FUNC_map_lookup_elem), BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1), BPF_ST_MEM(BPF_DW, BPF_REG_0, 4, 0), BPF_EXIT_INSN(), will be rejected with the following multi-line message in log_buf: 0: (7a) *(u64 *)(r10 -8) = 0 1: (bf) r2 = r10 2: (07) r2 += -8 3: (b7) r1 = 0 4: (85) call 1 5: (15) if r0 == 0x0 goto pc+1 R0=map_ptr R10=fp 6: (7a) *(u64 *)(r0 +4) = 0 misaligned access off 4 size 8 The format of the output can change at any time as verifier evolves. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: verifier (add docs)Alexei Starovoitov2014-09-263-2/+135
| | | | | | | | | | | | | | | | | | | | | | this patch adds all of eBPF verfier documentation and empty bpf_check() The end goal for the verifier is to statically check safety of the program. Verifier will catch: - loops - out of range jumps - unreachable instructions - invalid instructions - uninitialized register access - uninitialized stack access - misaligned stack access - out of range stack access - invalid calling convention More details in Documentation/networking/filter.txt Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: handle pseudo BPF_CALL insnAlexei Starovoitov2014-09-261-0/+37
| | | | | | | | | | | | | | in native eBPF programs userspace is using pseudo BPF_CALL instructions which encode one of 'enum bpf_func_id' inside insn->imm field. Verifier checks that program using correct function arguments to given func_id. If all checks passed, kernel needs to fixup BPF_CALL->imm fields by replacing func_id with in-kernel function pointer. eBPF interpreter just calls the function. In-kernel eBPF users continue to use generic BPF_CALL. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: expand BPF syscall with program load/unloadAlexei Starovoitov2014-09-262-14/+180
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | eBPF programs are similar to kernel modules. They are loaded by the user process and automatically unloaded when process exits. Each eBPF program is a safe run-to-completion set of instructions. eBPF verifier statically determines that the program terminates and is safe to execute. The following syscall wrapper can be used to load the program: int bpf_prog_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns, int insn_cnt, const char *license) { union bpf_attr attr = { .prog_type = prog_type, .insns = ptr_to_u64(insns), .insn_cnt = insn_cnt, .license = ptr_to_u64(license), }; return bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); } where 'insns' is an array of eBPF instructions and 'license' is a string that must be GPL compatible to call helper functions marked gpl_only Upon succesful load the syscall returns prog_fd. Use close(prog_fd) to unload the program. User space tests and examples follow in the later patches Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: add lookup/update/delete/iterate methods to BPF mapsAlexei Starovoitov2014-09-261-0/+235
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'maps' is a generic storage of different types for sharing data between kernel and userspace. The maps are accessed from user space via BPF syscall, which has commands: - create a map with given type and attributes fd = bpf(BPF_MAP_CREATE, union bpf_attr *attr, u32 size) returns fd or negative error - lookup key in a given map referenced by fd err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size) using attr->map_fd, attr->key, attr->value returns zero and stores found elem into value or negative error - create or update key/value pair in a given map err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size) using attr->map_fd, attr->key, attr->value returns zero or negative error - find and delete element by key in a given map err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size) using attr->map_fd, attr->key - iterate map elements (based on input key return next_key) err = bpf(BPF_MAP_GET_NEXT_KEY, union bpf_attr *attr, u32 size) using attr->map_fd, attr->key, attr->next_key - close(fd) deletes the map Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: introduce BPF syscall and mapsAlexei Starovoitov2014-09-262-1/+170
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BPF syscall is a multiplexor for a range of different operations on eBPF. This patch introduces syscall with single command to create a map. Next patch adds commands to access maps. 'maps' is a generic storage of different types for sharing data between kernel and userspace. Userspace example: /* this syscall wrapper creates a map with given type and attributes * and returns map_fd on success. * use close(map_fd) to delete the map */ int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size, int max_entries) { union bpf_attr attr = { .map_type = map_type, .key_size = key_size, .value_size = value_size, .max_entries = max_entries }; return bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); } 'union bpf_attr' is backwards compatible with future extensions. More details in Documentation/networking/filter.txt and in manpage Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: bpf: only build bpf_jit_binary_{alloc, free}() when jit selectedDaniel Borkmann2014-09-101-0/+2
| | | | | | | | | | | | | | | | | | | | | | Since BPF JIT depends on the availability of module_alloc() and module_free() helpers (HAVE_BPF_JIT and MODULES), we better build that code only in case we have BPF_JIT in our config enabled, just like with other JIT code. Fixes builds for arm/marzen_defconfig and sh/rsk7269_defconfig. ==================== kernel/built-in.o: In function `bpf_jit_binary_alloc': /home/cwang/linux/kernel/bpf/core.c:144: undefined reference to `module_alloc' kernel/built-in.o: In function `bpf_jit_binary_free': /home/cwang/linux/kernel/bpf/core.c:164: undefined reference to `module_free' make: *** [vmlinux] Error 1 ==================== Reported-by: Fengguang Wu <fengguang.wu@intel.com> Fixes: 738cbe72adc5 ("net: bpf: consolidate JIT binary allocator") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: bpf: consolidate JIT binary allocatorDaniel Borkmann2014-09-091-0/+39
| | | | | | | | | | | | | | | | | | | | | | | | | Introduced in commit 314beb9bcabf ("x86: bpf_jit_comp: secure bpf jit against spraying attacks") and later on replicated in aa2d2c73c21f ("s390/bpf,jit: address randomize and write protect jit code") for s390 architecture, write protection for BPF JIT images got added and a random start address of the JIT code, so that it's not on a page boundary anymore. Since both use a very similar allocator for the BPF binary header, we can consolidate this code into the BPF core as it's mostly JIT independant anyway. This will also allow for future archs that support DEBUG_SET_MODULE_RONX to just reuse instead of reimplementing it. JIT tested on x86_64 and s390x with BPF test suite. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: filter: add "load 64-bit immediate" eBPF instructionAlexei Starovoitov2014-09-091-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* net: bpf: make eBPF interpreter images read-onlyDaniel Borkmann2014-09-051-2/+78
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* net: filter: split 'struct sk_filter' into socket and bpf partsAlexei Starovoitov2014-08-021-16/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* net: filter: rename sk_convert_filter() -> bpf_convert_filter()Alexei Starovoitov2014-08-021-1/+1
| | | | | | | | to indicate that this function is converting classic BPF into eBPF and not related to sockets Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: filter: rename sk_chk_filter() -> bpf_check_classic()Alexei Starovoitov2014-08-021-1/+1
| | | | | | | trivial rename to indicate that this functions performs classic BPF checking Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: filter: rename 'struct sock_filter_int' into 'struct bpf_insn'Alexei Starovoitov2014-07-241-1/+1
| | | | | | | | | 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>
* net: filter: split filter.c into two filesAlexei Starovoitov2014-07-232-0/+537
BPF is used in several kernel components. This split creates logical boundary between generic eBPF core and the rest kernel/bpf/core.c: eBPF interpreter net/core/filter.c: classic->eBPF converter, classic verifiers, socket filters This patch only moves functions. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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