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2017-05-25bpf: fix wrong exposure of map_flags into fdinfo for lpmDaniel Borkmann3-0/+3
trie_alloc() always needs to have BPF_F_NO_PREALLOC passed in via attr->map_flags, since it does not support preallocation yet. We check the flag, but we never copy the flag into trie->map.map_flags, which is later on exposed into fdinfo and used by loaders such as iproute2. Latter uses this in bpf_map_selfcheck_pinned() to test whether a pinned map has the same spec as the one from the BPF obj file and if not, bails out, which is currently the case for lpm since it exposes always 0 as flags. Also copy over flags in array_map_alloc() and stack_map_alloc(). They always have to be 0 right now, but we should make sure to not miss to copy them over at a later point in time when we add actual flags for them to use. Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation") Reported-by: Jarno Rajahalme <jarno@covalent.io> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-25bpf: properly reset caller saved regs after helper call and ld_abs/indDaniel Borkmann1-21/+16
Currently, after performing helper calls, we clear all caller saved registers, that is r0 - r5 and fill r0 depending on struct bpf_func_proto specification. The way we reset these regs can affect pruning decisions in later paths, since we only reset register's imm to 0 and type to NOT_INIT. However, we leave out clearing of other variables such as id, min_value, max_value, etc, which can later on lead to pruning mismatches due to stale data. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-25bpf: fix incorrect pruning decision when alignment must be trackedDaniel Borkmann1-9/+10
Currently, when we enforce alignment tracking on direct packet access, the verifier lets the following program pass despite doing a packet write with unaligned access: 0: (61) r2 = *(u32 *)(r1 +76) 1: (61) r3 = *(u32 *)(r1 +80) 2: (61) r7 = *(u32 *)(r1 +8) 3: (bf) r0 = r2 4: (07) r0 += 14 5: (25) if r7 > 0x1 goto pc+4 R0=pkt(id=0,off=14,r=0) R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R7=inv,min_value=0,max_value=1 R10=fp 6: (2d) if r0 > r3 goto pc+1 R0=pkt(id=0,off=14,r=14) R1=ctx R2=pkt(id=0,off=0,r=14) R3=pkt_end R7=inv,min_value=0,max_value=1 R10=fp 7: (63) *(u32 *)(r0 -4) = r0 8: (b7) r0 = 0 9: (95) exit from 6 to 8: R0=pkt(id=0,off=14,r=0) R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R7=inv,min_value=0,max_value=1 R10=fp 8: (b7) r0 = 0 9: (95) exit from 5 to 10: R0=pkt(id=0,off=14,r=0) R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R7=inv,min_value=2 R10=fp 10: (07) r0 += 1 11: (05) goto pc-6 6: safe <----- here, wrongly found safe processed 15 insns However, if we enforce a pruning mismatch by adding state into r8 which is then being mismatched in states_equal(), we find that for the otherwise same program, the verifier detects a misaligned packet access when actually walking that path: 0: (61) r2 = *(u32 *)(r1 +76) 1: (61) r3 = *(u32 *)(r1 +80) 2: (61) r7 = *(u32 *)(r1 +8) 3: (b7) r8 = 1 4: (bf) r0 = r2 5: (07) r0 += 14 6: (25) if r7 > 0x1 goto pc+4 R0=pkt(id=0,off=14,r=0) R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R7=inv,min_value=0,max_value=1 R8=imm1,min_value=1,max_value=1,min_align=1 R10=fp 7: (2d) if r0 > r3 goto pc+1 R0=pkt(id=0,off=14,r=14) R1=ctx R2=pkt(id=0,off=0,r=14) R3=pkt_end R7=inv,min_value=0,max_value=1 R8=imm1,min_value=1,max_value=1,min_align=1 R10=fp 8: (63) *(u32 *)(r0 -4) = r0 9: (b7) r0 = 0 10: (95) exit from 7 to 9: R0=pkt(id=0,off=14,r=0) R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R7=inv,min_value=0,max_value=1 R8=imm1,min_value=1,max_value=1,min_align=1 R10=fp 9: (b7) r0 = 0 10: (95) exit from 6 to 11: R0=pkt(id=0,off=14,r=0) R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R7=inv,min_value=2 R8=imm1,min_value=1,max_value=1,min_align=1 R10=fp 11: (07) r0 += 1 12: (b7) r8 = 0 13: (05) goto pc-7 <----- mismatch due to r8 7: (2d) if r0 > r3 goto pc+1 R0=pkt(id=0,off=15,r=15) R1=ctx R2=pkt(id=0,off=0,r=15) R3=pkt_end R7=inv,min_value=2 R8=imm0,min_value=0,max_value=0,min_align=2147483648 R10=fp 8: (63) *(u32 *)(r0 -4) = r0 misaligned packet access off 2+15+-4 size 4 The reason why we fail to see it in states_equal() is that the third test in compare_ptrs_to_packet() ... if (old->off <= cur->off && old->off >= old->range && cur->off >= cur->range) return true; ... will let the above pass. The situation we run into is that old->off <= cur->off (14 <= 15), meaning that prior walked paths went with smaller offset, which was later used in the packet access after successful packet range check and found to be safe already. For example: Given is R0=pkt(id=0,off=0,r=0). Adding offset 14 as in above program to it, results in R0=pkt(id=0,off=14,r=0) before the packet range test. Now, testing this against R3=pkt_end with 'if r0 > r3 goto out' will transform R0 into R0=pkt(id=0,off=14,r=14) for the case when we're within bounds. A write into the packet at offset *(u32 *)(r0 -4), that is, 2 + 14 -4, is valid and aligned (2 is for NET_IP_ALIGN). After processing this with all fall-through paths, we later on check paths from branches. When the above skb->mark test is true, then we jump near the end of the program, perform r0 += 1, and jump back to the 'if r0 > r3 goto out' test we've visited earlier already. This time, R0 is of type R0=pkt(id=0,off=15,r=0), and we'll prune that part because this time we'll have a larger safe packet range, and we already found that with off=14 all further insn were already safe, so it's safe as well with a larger off. However, the problem is that the subsequent write into the packet with 2 + 15 -4 is then unaligned, and not caught by the alignment tracking. Note that min_align, aux_off, and aux_off_align were all 0 in this example. Since we cannot tell at this time what kind of packet access was performed in the prior walk and what minimal requirements it has (we might do so in the future, but that requires more complexity), fix it to disable this pruning case for strict alignment for now, and let the verifier do check such paths instead. With that applied, the test cases pass and reject the program due to misalignment. Fixes: d1174416747d ("bpf: Track alignment of register values in the verifier.") Reference: http://patchwork.ozlabs.org/patch/761909/ Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-22net: Make IP alignment calulations clearer.David S. Miller1-4/+8
The assignmnet: ip_align = strict ? 2 : NET_IP_ALIGN; in compare_pkt_ptr_alignment() trips up Coverity because we can only get to this code when strict is true, therefore ip_align will always be 2 regardless of NET_IP_ALIGN's value. So just assign directly to '2' and explain the situation in the comment above. Reported-by: "Gustavo A. R. Silva" <garsilva@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17bpf: adjust verifier heuristicsDaniel Borkmann1-1/+11
Current limits with regards to processing program paths do not really reflect today's needs anymore due to programs becoming more complex and verifier smarter, keeping track of more data such as const ALU operations, alignment tracking, spilling of PTR_TO_MAP_VALUE_ADJ registers, and other features allowing for smarter matching of what LLVM generates. This also comes with the side-effect that we result in fewer opportunities to prune search states and thus often need to do more work to prove safety than in the past due to different register states and stack layout where we mismatch. Generally, it's quite hard to determine what caused a sudden increase in complexity, it could be caused by something as trivial as a single branch somewhere at the beginning of the program where LLVM assigned a stack slot that is marked differently throughout other branches and thus causing a mismatch, where verifier then needs to prove safety for the whole rest of the program. Subsequently, programs with even less than half the insn size limit can get rejected. We noticed that while some programs load fine under pre 4.11, they get rejected due to hitting limits on more recent kernels. We saw that in the vast majority of cases (90+%) pruning failed due to register mismatches. In case of stack mismatches, majority of cases failed due to different stack slot types (invalid, spill, misc) rather than differences in spilled registers. This patch makes pruning more aggressive by also adding markers that sit at conditional jumps as well. Currently, we only mark jump targets for pruning. For example in direct packet access, these are usually error paths where we bail out. We found that adding these markers, it can reduce number of processed insns by up to 30%. Another option is to ignore reg->id in probing PTR_TO_MAP_VALUE_OR_NULL registers, which can help pruning slightly as well by up to 7% observed complexity reduction as stand-alone. Meaning, if a previous path with register type PTR_TO_MAP_VALUE_OR_NULL for map X was found to be safe, then in the current state a PTR_TO_MAP_VALUE_OR_NULL register for the same map X must be safe as well. Last but not least the patch also adds a scheduling point and bumps the current limit for instructions to be processed to a more adequate value. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-11bpf: Handle multiple variable additions into packet pointers in verifier.David S. Miller1-1/+1
We must accumulate into reg->aux_off rather than use a plain assignment. Add a test for this situation to test_align. Reported-by: Alexei Starovoitov <ast@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-11bpf: Add strict alignment flag for BPF_PROG_LOAD.David S. Miller2-7/+21
Add a new field, "prog_flags", and an initial flag value BPF_F_STRICT_ALIGNMENT. When set, the verifier will enforce strict pointer alignment regardless of the setting of CONFIG_EFFICIENT_UNALIGNED_ACCESS. The verifier, in this mode, will also use a fixed value of "2" in place of NET_IP_ALIGN. This facilitates test cases that will exercise and validate this part of the verifier even when run on architectures where alignment doesn't matter. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
2017-05-11bpf: Do per-instruction state dumping in verifier when log_level > 1.David S. Miller1-2/+6
If log_level > 1, do a state dump every instruction and emit it in a more compact way (without a leading newline). This will facilitate more sophisticated test cases which inspect the verifier log for register state. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
2017-05-11bpf: Track alignment of register values in the verifier.David S. Miller1-19/+89
Currently if we add only constant values to pointers we can fully validate the alignment, and properly check if we need to reject the program on !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS architectures. However, once an unknown value is introduced we only allow byte sized memory accesses which is too restrictive. Add logic to track the known minimum alignment of register values, and propagate this state into registers containing pointers. The most common paradigm that makes use of this new logic is computing the transport header using the IP header length field. For example: struct ethhdr *ep = skb->data; struct iphdr *iph = (struct iphdr *) (ep + 1); struct tcphdr *th; ... n = iph->ihl; th = ((void *)iph + (n * 4)); port = th->dest; The existing code will reject the load of th->dest because it cannot validate that the alignment is at least 2 once "n * 4" is added the the packet pointer. In the new code, the register holding "n * 4" will have a reg->min_align value of 4, because any value multiplied by 4 will be at least 4 byte aligned. (actually, the eBPF code emitted by the compiler in this case is most likely to use a shift left by 2, but the end result is identical) At the critical addition: th = ((void *)iph + (n * 4)); The register holding 'th' will start with reg->off value of 14. The pointer addition will transform that reg into something that looks like: reg->aux_off = 14 reg->aux_off_align = 4 Next, the verifier will look at the th->dest load, and it will see a load offset of 2, and first check: if (reg->aux_off_align % size) which will pass because aux_off_align is 4. reg_off will be computed: reg_off = reg->off; ... reg_off += reg->aux_off; plus we have off==2, and it will thus check: if ((NET_IP_ALIGN + reg_off + off) % size != 0) which evaluates to: if ((NET_IP_ALIGN + 14 + 2) % size != 0) On strict alignment architectures, NET_IP_ALIGN is 2, thus: if ((2 + 14 + 2) % size != 0) which passes. These pointer transformations and checks work regardless of whether the constant offset or the variable with known alignment is added first to the pointer register. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
2017-05-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds1-5/+16
Pull networking fixes from David Miller: 1) Fix multiqueue in stmmac driver on PCI, from Andy Shevchenko. 2) cdc_ncm doesn't actually fully zero out the padding area is allocates on TX, from Jim Baxter. 3) Don't leak map addresses in BPF verifier, from Daniel Borkmann. 4) If we randomize TCP timestamps, we have to do it everywhere including SYN cookies. From Eric Dumazet. 5) Fix "ethtool -S" crash in aquantia driver, from Pavel Belous. 6) Fix allocation size for ntp filter bitmap in bnxt_en driver, from Dan Carpenter. 7) Add missing memory allocation return value check to DSA loop driver, from Christophe Jaillet. 8) Fix XDP leak on driver unload in qed driver, from Suddarsana Reddy Kalluru. 9) Don't inherit MC list from parent inet connection sockets, another syzkaller spotted gem. Fix from Eric Dumazet. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (43 commits) dccp/tcp: do not inherit mc_list from parent qede: Split PF/VF ndos. qed: Correct doorbell configuration for !4Kb pages qed: Tell QM the number of tasks qed: Fix VF removal sequence qede: Fix XDP memory leak on unload net/mlx4_core: Reduce harmless SRIOV error message to debug level net/mlx4_en: Avoid adding steering rules with invalid ring net/mlx4_en: Change the error print to debug print drivers: net: wimax: i2400m: i2400m-usb: Use time_after for time comparison DECnet: Use container_of() for embedded struct Revert "ipv4: restore rt->fi for reference counting" net: mdio-mux: bcm-iproc: call mdiobus_free() in error path net: ethernet: ti: cpsw: adjust cpsw fifos depth for fullduplex flow control ipv6: reorder ip6_route_dev_notifier after ipv6_dev_notf net: cdc_ncm: Fix TX zero padding stmmac: pci: split out common_default_data() helper stmmac: pci: RX queue routing configuration stmmac: pci: TX and RX queue priority configuration stmmac: pci: set default number of rx and tx queues ...
2017-05-09Merge branch 'work.misc' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Assorted bits and pieces from various people. No common topic in this pile, sorry" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs/affs: add rename exchange fs/affs: add rename2 to prepare multiple methods Make stat/lstat/fstatat pass AT_NO_AUTOMOUNT to vfs_statx() fs: don't set *REFERENCED on single use objects fs: compat: Remove warning from COMPATIBLE_IOCTL remove pointless extern of atime_need_update_rcu() fs: completely ignore unknown open flags fs: add a VALID_OPEN_FLAGS fs: remove _submit_bh() fs: constify tree_descr arrays passed to simple_fill_super() fs: drop duplicate header percpu-rwsem.h fs/affs: bugfix: Write files greater than page size on OFS fs/affs: bugfix: enable writes on OFS disks fs/affs: remove node generation check fs/affs: import amigaffs.h fs/affs: bugfix: make symbolic links work again
2017-05-08mm, vmalloc: use __GFP_HIGHMEM implicitlyMichal Hocko2-8/+4
__vmalloc* allows users to provide gfp flags for the underlying allocation. This API is quite popular $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l 77 The only problem is that many people are not aware that they really want to give __GFP_HIGHMEM along with other flags because there is really no reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages which are mapped to the kernel vmalloc space. About half of users don't use this flag, though. This signals that we make the API unnecessarily too complex. This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to be mapped to the vmalloc space. Current users which add __GFP_HIGHMEM are simplified and drop the flag. Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Cristopher Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08bpf: don't let ldimm64 leak map addresses on unprivilegedDaniel Borkmann1-5/+16
The patch fixes two things at once: 1) It checks the env->allow_ptr_leaks and only prints the map address to the log if we have the privileges to do so, otherwise it just dumps 0 as we would when kptr_restrict is enabled on %pK. Given the latter is off by default and not every distro sets it, I don't want to rely on this, hence the 0 by default for unprivileged. 2) Printing of ldimm64 in the verifier log is currently broken in that we don't print the full immediate, but only the 32 bit part of the first insn part for ldimm64. Thus, fix this up as well; it's okay to access, since we verified all ldimm64 earlier already (including just constants) through replace_map_fd_with_map_ptr(). Fixes: 1be7f75d1668 ("bpf: enable non-root eBPF programs") Fixes: cbd357008604 ("bpf: verifier (add ability to receive verification log)") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-01bpf: enhance verifier to understand stack pointer arithmeticYonghong Song1-0/+11
llvm 4.0 and above generates the code like below: .... 440: (b7) r1 = 15 441: (05) goto pc+73 515: (79) r6 = *(u64 *)(r10 -152) 516: (bf) r7 = r10 517: (07) r7 += -112 518: (bf) r2 = r7 519: (0f) r2 += r1 520: (71) r1 = *(u8 *)(r8 +0) 521: (73) *(u8 *)(r2 +45) = r1 .... and the verifier complains "R2 invalid mem access 'inv'" for insn #521. This is because verifier marks register r2 as unknown value after #519 where r2 is a stack pointer and r1 holds a constant value. Teach verifier to recognize "stack_ptr + imm" and "stack_ptr + reg with const val" as valid stack_ptr with new offset. Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-28bpf: bpf_lock on kallsysms doesn't need to be irqsaveHannes Frederic Sowa1-8/+4
Hannes rightfully spotted that the bpf_lock doesn't need to be irqsave variant. We never perform any such updates where this would be necessary (neither right now nor in future), therefore relax this further. Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-26fs: constify tree_descr arrays passed to simple_fill_super()Eric Biggers1-1/+1
simple_fill_super() is passed an array of tree_descr structures which describe the files to create in the filesystem's root directory. Since these arrays are never modified intentionally, they should be 'const' so that they are placed in .rodata and benefit from memory protection. This patch updates the function signature and all users, and also constifies tree_descr.name. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-25bpf: map_get_next_key to return first key on NULLTeng Qin3-13/+18
When iterating through a map, we need to find a key that does not exist in the map so map_get_next_key will give us the first key of the map. This often requires a lot of guessing in production systems. This patch makes map_get_next_key return the first key when the key pointer in the parameter is NULL. Signed-off-by: Teng Qin <qinteng@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-24bpf: make bpf_xdp_adjust_head support mandatoryDaniel Borkmann1-3/+0
Now that also the last in-tree user of the xdp_adjust_head bit has been removed, we can remove the flag from struct bpf_prog altogether. This, at the same time, also makes sure that any future driver for XDP comes with bpf_xdp_adjust_head() support right away. A rejection based on this flag would also mean that tail calls couldn't be used with such driver as per c2002f983767 ("bpf: fix checking xdp_adjust_head on tail calls") fix, thus lets not allow for it in the first place. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-20Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-0/+8
A function in kernel/bpf/syscall.c which got a bug fix in 'net' was moved to kernel/bpf/verifier.c in 'net-next'. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-17bpf: fix checking xdp_adjust_head on tail callsDaniel Borkmann1-0/+1
Commit 17bedab27231 ("bpf: xdp: Allow head adjustment in XDP prog") added the xdp_adjust_head bit to the BPF prog in order to tell drivers that the program that is to be attached requires support for the XDP bpf_xdp_adjust_head() helper such that drivers not supporting this helper can reject the program. There are also drivers that do support the helper, but need to check for xdp_adjust_head bit in order to move packet metadata prepended by the firmware away for making headroom. For these cases, the current check for xdp_adjust_head bit is insufficient since there can be cases where the program itself does not use the bpf_xdp_adjust_head() helper, but tail calls into another program that uses bpf_xdp_adjust_head(). As such, the xdp_adjust_head bit is still set to 0. Since the first program has no control over which program it calls into, we need to assume that bpf_xdp_adjust_head() helper is used upon tail calls. Thus, for the very same reasons in cb_access, set the xdp_adjust_head bit to 1 when the main program uses tail calls. Fixes: 17bedab27231 ("bpf: xdp: Allow head adjustment in XDP prog") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-17bpf: fix cb access in socket filter programs on tail callsDaniel Borkmann1-0/+7
Commit ff936a04e5f2 ("bpf: fix cb access in socket filter programs") added a fix for socket filter programs such that in i) AF_PACKET the 20 bytes of skb->cb[] area gets zeroed before use in order to not leak data, and ii) socket filter programs attached to TCP/UDP sockets need to save/restore these 20 bytes since they are also used by protocol layers at that time. The problem is that bpf_prog_run_save_cb() and bpf_prog_run_clear_cb() only look at the actual attached program to determine whether to zero or save/restore the skb->cb[] parts. There can be cases where the actual attached program does not access the skb->cb[], but the program tail calls into another program which does access this area. In such a case, the zero or save/restore is currently not performed. Since the programs we tail call into are unknown at verification time and can dynamically change, we need to assume that whenever the attached program performs a tail call, that later programs could access the skb->cb[], and therefore we need to always set cb_access to 1. Fixes: ff936a04e5f2 ("bpf: fix cb access in socket filter programs") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-17bpf: lru: Lower the PERCPU_NR_SCANS from 16 to 4Martin KaFai Lau1-1/+1
After doing map_perf_test with a much bigger BPF_F_NO_COMMON_LRU map, the perf report shows a lot of time spent in rotating the inactive list (i.e. __bpf_lru_list_rotate_inactive): > map_perf_test 32 8 10000 1000000 | awk '{sum += $3}END{print sum}' 19644783 (19M/s) > map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}' 6283930 (6.28M/s) By inactive, it usually means the element is not in cache. Hence, there is a need to tune the PERCPU_NR_SCANS value. This patch finds a better number of elements to scan during each list rotation. The PERCPU_NR_SCANS (which is defined the same as PERCPU_FREE_TARGET) decreases from 16 elements to 4 elements. This change only affects the BPF_F_NO_COMMON_LRU map. The test_lru_dist does not show meaningful difference between 16 and 4. Our production L4 load balancer which uses the LRU map for conntrack-ing also shows little change in cache hit rate. Since both benchmark and production data show no cache-hit difference, PERCPU_NR_SCANS is lowered from 16 to 4. We can consider making it configurable if we find a usecase later that shows another value works better and/or use a different rotation strategy. After this change: > map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}' 9240324 (9.2M/s) i.e. 6.28M/s -> 9.2M/s The test_lru_dist has not shown meaningful difference: > test_lru_dist zipf.100k.a1_01.out 4000 1: nr_misses: 31575 (Before) vs 31566 (After) > test_lru_dist zipf.100k.a0_01.out 40000 1 nr_misses: 67036 (Before) vs 67031 (After) Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-6/+6
Conflicts were simply overlapping changes. In the net/ipv4/route.c case the code had simply moved around a little bit and the same fix was made in both 'net' and 'net-next'. In the net/sched/sch_generic.c case a fix in 'net' happened at the same time that a new argument was added to qdisc_hash_add(). Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-11bpf: pass sk to helper functionsWillem de Bruijn1-1/+4
BPF helper functions access socket fields through skb->sk. This is not set in ingress cgroup and socket filters. The association is only made in skb_set_owner_r once the filter has accepted the packet. Sk is available as socket lookup has taken place. Temporarily set skb->sk to sk in these cases. Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-11bpf: remove struct bpf_map_type_listJohannes Berg5-157/+32
There's no need to have struct bpf_map_type_list since it just contains a list_head, the type, and the ops pointer. Since the types are densely packed and not actually dynamically registered, it's much easier and smaller to have an array of type->ops pointer. Also initialize this array statically to remove code needed to initialize it. In order to save duplicating the list, move it to the types header file added by the previous patch and include it in the same fashion. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-11bpf: remove struct bpf_prog_type_listJohannes Berg1-16/+11
There's no need to have struct bpf_prog_type_list since it just contains a list_head, the type, and the ops pointer. Since the types are densely packed and not actually dynamically registered, it's much easier and smaller to have an array of type->ops pointer. Also initialize this array statically to remove code needed to initialize it. In order to save duplicating the list, move it to a new header file and include it in the places needing it. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-11bpf: reference may_access_skb() from __bpf_prog_run()Johannes Berg1-6/+6
It took me quite some time to figure out how this was linked, so in order to save the next person the effort of finding it add a comment in __bpf_prog_run() that indicates what exactly determines that a program can access the ctx == skb. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-22/+42
Mostly simple cases of overlapping changes (adding code nearby, a function whose name changes, for example). Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-01bpf: introduce BPF_PROG_TEST_RUN commandAlexei Starovoitov1-2/+25
development and testing of networking bpf programs is quite cumbersome. Despite availability of user space bpf interpreters the kernel is the ultimate authority and execution environment. Current test frameworks for TC include creation of netns, veth, qdiscs and use of various packet generators just to test functionality of a bpf program. XDP testing is even more complicated, since qemu needs to be started with gro/gso disabled and precise queue configuration, transferring of xdp program from host into guest, attaching to virtio/eth0 and generating traffic from the host while capturing the results from the guest. Moreover analyzing performance bottlenecks in XDP program is impossible in virtio environment, since cost of running the program is tiny comparing to the overhead of virtio packet processing, so performance testing can only be done on physical nic with another server generating traffic. Furthermore ongoing changes to user space control plane of production applications cannot be run on the test servers leaving bpf programs stubbed out for testing. Last but not least, the upstream llvm changes are validated by the bpf backend testsuite which has no ability to test the code generated. To improve this situation introduce BPF_PROG_TEST_RUN command to test and performance benchmark bpf programs. Joint work with Daniel Borkmann. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-01bpf, verifier: fix rejection of unaligned access checks for map_value_adjDaniel Borkmann1-20/+38
Currently, the verifier doesn't reject unaligned access for map_value_adj register types. Commit 484611357c19 ("bpf: allow access into map value arrays") added logic to check_ptr_alignment() extending it from PTR_TO_PACKET to also PTR_TO_MAP_VALUE_ADJ, but for PTR_TO_MAP_VALUE_ADJ no enforcement is in place, because reg->id for PTR_TO_MAP_VALUE_ADJ reg types is never non-zero, meaning, we can cause BPF_H/_W/_DW-based unaligned access for architectures not supporting efficient unaligned access, and thus worst case could raise exceptions on some archs that are unable to correct the unaligned access or perform a different memory access to the actual requested one and such. i) Unaligned load with !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS on r0 (map_value_adj): 0: (bf) r2 = r10 1: (07) r2 += -8 2: (7a) *(u64 *)(r2 +0) = 0 3: (18) r1 = 0x42533a00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+11 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 7: (61) r1 = *(u32 *)(r0 +0) 8: (35) if r1 >= 0xb goto pc+9 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R1=inv,min_value=0,max_value=10 R10=fp 9: (07) r0 += 3 10: (79) r7 = *(u64 *)(r0 +0) R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R1=inv,min_value=0,max_value=10 R10=fp 11: (79) r7 = *(u64 *)(r0 +2) R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R1=inv,min_value=0,max_value=10 R7=inv R10=fp [...] ii) Unaligned store with !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS on r0 (map_value_adj): 0: (bf) r2 = r10 1: (07) r2 += -8 2: (7a) *(u64 *)(r2 +0) = 0 3: (18) r1 = 0x4df16a00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+19 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 7: (07) r0 += 3 8: (7a) *(u64 *)(r0 +0) = 42 R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R10=fp 9: (7a) *(u64 *)(r0 +2) = 43 R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R10=fp 10: (7a) *(u64 *)(r0 -2) = 44 R0=map_value_adj(ks=8,vs=48,id=0),min_value=3,max_value=3 R10=fp [...] For the PTR_TO_PACKET type, reg->id is initially zero when skb->data was fetched, it later receives a reg->id from env->id_gen generator once another register with UNKNOWN_VALUE type was added to it via check_packet_ptr_add(). The purpose of this reg->id is twofold: i) it is used in find_good_pkt_pointers() for setting the allowed access range for regs with PTR_TO_PACKET of same id once verifier matched on data/data_end tests, and ii) for check_ptr_alignment() to determine that when not having efficient unaligned access and register with UNKNOWN_VALUE was added to PTR_TO_PACKET, that we're only allowed to access the content bytewise due to unknown unalignment. reg->id was never intended for PTR_TO_MAP_VALUE{,_ADJ} types and thus is always zero, the only marking is in PTR_TO_MAP_VALUE_OR_NULL that was added after 484611357c19 via 57a09bf0a416 ("bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registers"). Above tests will fail for non-root environment due to prohibited pointer arithmetic. The fix splits register-type specific checks into their own helper instead of keeping them combined, so we don't run into a similar issue in future once we extend check_ptr_alignment() further and forget to add reg->type checks for some of the checks. Fixes: 484611357c19 ("bpf: allow access into map value arrays") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Josef Bacik <jbacik@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-01bpf, verifier: fix alu ops against map_value{, _adj} register typesDaniel Borkmann1-0/+1
While looking into map_value_adj, I noticed that alu operations directly on the map_value() resp. map_value_adj() register (any alu operation on a map_value() register will turn it into a map_value_adj() typed register) are not sufficiently protected against some of the operations. Two non-exhaustive examples are provided that the verifier needs to reject: i) BPF_AND on r0 (map_value_adj): 0: (bf) r2 = r10 1: (07) r2 += -8 2: (7a) *(u64 *)(r2 +0) = 0 3: (18) r1 = 0xbf842a00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+2 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 7: (57) r0 &= 8 8: (7a) *(u64 *)(r0 +0) = 22 R0=map_value_adj(ks=8,vs=48,id=0),min_value=0,max_value=8 R10=fp 9: (95) exit from 6 to 9: R0=inv,min_value=0,max_value=0 R10=fp 9: (95) exit processed 10 insns ii) BPF_ADD in 32 bit mode on r0 (map_value_adj): 0: (bf) r2 = r10 1: (07) r2 += -8 2: (7a) *(u64 *)(r2 +0) = 0 3: (18) r1 = 0xc24eee00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+2 R0=map_value(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 7: (04) (u32) r0 += (u32) 0 8: (7a) *(u64 *)(r0 +0) = 22 R0=map_value_adj(ks=8,vs=48,id=0),min_value=0,max_value=0 R10=fp 9: (95) exit from 6 to 9: R0=inv,min_value=0,max_value=0 R10=fp 9: (95) exit processed 10 insns Issue is, while min_value / max_value boundaries for the access are adjusted appropriately, we change the pointer value in a way that cannot be sufficiently tracked anymore from its origin. Operations like BPF_{AND,OR,DIV,MUL,etc} on a destination register that is PTR_TO_MAP_VALUE{,_ADJ} was probably unintended, in fact, all the test cases coming with 484611357c19 ("bpf: allow access into map value arrays") perform BPF_ADD only on the destination register that is PTR_TO_MAP_VALUE_ADJ. Only for UNKNOWN_VALUE register types such operations make sense, f.e. with unknown memory content fetched initially from a constant offset from the map value memory into a register. That register is then later tested against lower / upper bounds, so that the verifier can then do the tracking of min_value / max_value, and properly check once that UNKNOWN_VALUE register is added to the destination register with type PTR_TO_MAP_VALUE{,_ADJ}. This is also what the original use-case is solving. Note, tracking on what is being added is done through adjust_reg_min_max_vals() and later access to the map value enforced with these boundaries and the given offset from the insn through check_map_access_adj(). Tests will fail for non-root environment due to prohibited pointer arithmetic, in particular in check_alu_op(), we bail out on the is_pointer_value() check on the dst_reg (which is false in root case as we allow for pointer arithmetic via env->allow_ptr_leaks). Similarly to PTR_TO_PACKET, one way to fix it is to restrict the allowed operations on PTR_TO_MAP_VALUE{,_ADJ} registers to 64 bit mode BPF_ADD. The test_verifier suite runs fine after the patch and it also rejects mentioned test cases. Fixes: 484611357c19 ("bpf: allow access into map value arrays") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Josef Bacik <jbacik@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-24bpf: improve verifier packet range checksAlexei Starovoitov1-2/+3
llvm can optimize the 'if (ptr > data_end)' checks to be in the order slightly different than the original C code which will confuse verifier. Like: if (ptr + 16 > data_end) return TC_ACT_SHOT; // may be followed by if (ptr + 14 > data_end) return TC_ACT_SHOT; while llvm can see that 'ptr' is valid for all 16 bytes, the verifier could not. Fix verifier logic to account for such case and add a test. Reported-by: Huapeng Zhou <hzhou@fb.com> Fixes: 969bf05eb3ce ("bpf: direct packet access") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-73/+71
Conflicts: drivers/net/ethernet/broadcom/genet/bcmmii.c drivers/net/hyperv/netvsc.c kernel/bpf/hashtab.c Almost entirely overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-22bpf: Add hash of maps supportMartin KaFai Lau3-2/+131
This patch adds hash of maps support (hashmap->bpf_map). BPF_MAP_TYPE_HASH_OF_MAPS is added. A map-in-map contains a pointer to another map and lets call this pointer 'inner_map_ptr'. Notes on deleting inner_map_ptr from a hash map: 1. For BPF_F_NO_PREALLOC map-in-map, when deleting an inner_map_ptr, the htab_elem itself will go through a rcu grace period and the inner_map_ptr resides in the htab_elem. 2. For pre-allocated htab_elem (!BPF_F_NO_PREALLOC), when deleting an inner_map_ptr, the htab_elem may get reused immediately. This situation is similar to the existing prealloc-ated use cases. However, the bpf_map_fd_put_ptr() calls bpf_map_put() which calls inner_map->ops->map_free(inner_map) which will go through a rcu grace period (i.e. all bpf_map's map_free currently goes through a rcu grace period). Hence, the inner_map_ptr is still safe for the rcu reader side. This patch also includes BPF_MAP_TYPE_HASH_OF_MAPS to the check_map_prealloc() in the verifier. preallocation is a must for BPF_PROG_TYPE_PERF_EVENT. Hence, even we don't expect heavy updates to map-in-map, enforcing BPF_F_NO_PREALLOC for map-in-map is impossible without disallowing BPF_PROG_TYPE_PERF_EVENT from using map-in-map first. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-22bpf: Add array of maps supportMartin KaFai Lau6-12/+222
This patch adds a few helper funcs to enable map-in-map support (i.e. outer_map->inner_map). The first outer_map type BPF_MAP_TYPE_ARRAY_OF_MAPS is also added in this patch. The next patch will introduce a hash of maps type. Any bpf map type can be acted as an inner_map. The exception is BPF_MAP_TYPE_PROG_ARRAY because the extra level of indirection makes it harder to verify the owner_prog_type and owner_jited. Multi-level map-in-map is not supported (i.e. map->map is ok but not map->map->map). When adding an inner_map to an outer_map, it currently checks the map_type, key_size, value_size, map_flags, max_entries and ops. The verifier also uses those map's properties to do static analysis. map_flags is needed because we need to ensure BPF_PROG_TYPE_PERF_EVENT is using a preallocated hashtab for the inner_hash also. ops and max_entries are needed to generate inlined map-lookup instructions. For simplicity reason, a simple '==' test is used for both map_flags and max_entries. The equality of ops is implied by the equality of map_type. During outer_map creation time, an inner_map_fd is needed to create an outer_map. However, the inner_map_fd's life time does not depend on the outer_map. The inner_map_fd is merely used to initialize the inner_map_meta of the outer_map. Also, for the outer_map: * It allows element update and delete from syscall * It allows element lookup from bpf_prog The above is similar to the current fd_array pattern. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-22bpf: Fix and simplifications on inline map lookupMartin KaFai Lau2-9/+15
Fix in verifier: For the same bpf_map_lookup_elem() instruction (i.e. "call 1"), a broken case is "a different type of map could be used for the same lookup instruction". For example, an array in one case and a hashmap in another. We have to resort to the old dynamic call behavior in this case. The fix is to check for collision on insn_aux->map_ptr. If there is collision, don't inline the map lookup. Please see the "do_reg_lookup()" in test_map_in_map_kern.c in the later patch for how-to trigger the above case. Simplifications on array_map_gen_lookup(): 1. Calculate elem_size from map->value_size. It removes the need for 'struct bpf_array' which makes the later map-in-map implementation easier. 2. Remove the 'elem_size == 1' test Fixes: 81ed18ab3098 ("bpf: add helper inlining infra and optimize map_array lookup") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-22bpf: fix hashmap extra_elems logicAlexei Starovoitov1-73/+71
In both kmalloc and prealloc mode the bpf_map_update_elem() is using per-cpu extra_elems to do atomic update when the map is full. There are two issues with it. The logic can be misused, since it allows max_entries+num_cpus elements to be present in the map. And alloc_extra_elems() at map creation time can fail percpu alloc for large map values with a warn: WARNING: CPU: 3 PID: 2752 at ../mm/percpu.c:892 pcpu_alloc+0x119/0xa60 illegal size (32824) or align (8) for percpu allocation The fixes for both of these issues are different for kmalloc and prealloc modes. For prealloc mode allocate extra num_possible_cpus elements and store their pointers into extra_elems array instead of actual elements. Hence we can use these hidden(spare) elements not only when the map is full but during bpf_map_update_elem() that replaces existing element too. That also improves performance, since pcpu_freelist_pop/push is avoided. Unfortunately this approach cannot be used for kmalloc mode which needs to kfree elements after rcu grace period. Therefore switch it back to normal kmalloc even when full and old element exists like it was prior to commit 6c9059817432 ("bpf: pre-allocate hash map elements"). Add tests to check for over max_entries and large map values. Reported-by: Dave Jones <davej@codemonkey.org.uk> Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16bpf: inline htab_map_lookup_elem()Alexei Starovoitov1-1/+30
Optimize: bpf_call bpf_map_lookup_elem map->ops->map_lookup_elem htab_map_lookup_elem __htab_map_lookup_elem into: bpf_call __htab_map_lookup_elem to improve performance of JITed programs. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16bpf: add helper inlining infra and optimize map_array lookupAlexei Starovoitov2-3/+62
Optimize bpf_call -> bpf_map_lookup_elem() -> array_map_lookup_elem() into a sequence of bpf instructions. When JIT is on the sequence of bpf instructions is the sequence of native cpu instructions with significantly faster performance than indirect call and two function's prologue/epilogue. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16bpf: adjust insn_aux_data when patching insnsAlexei Starovoitov1-5/+39
convert_ctx_accesses() replaces single bpf instruction with a set of instructions. Adjust corresponding insn_aux_data while patching. It's needed to make sure subsequent 'for(all insn)' loops have matching insn and insn_aux_data. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16bpf: refactor fixup_bpf_calls()Alexei Starovoitov1-41/+35
reduce indent and make it iterate over instructions similar to convert_ctx_accesses(). Also convert hard BUG_ON into soft verifier error. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16bpf: move fixup_bpf_calls() functionAlexei Starovoitov2-56/+57
no functional change. move fixup_bpf_calls() to verifier.c it's being refactored in the next patch Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-09bpf: convert htab map to hlist_nullsAlexei Starovoitov1-34/+60
when all map elements are pre-allocated one cpu can delete and reuse htab_elem while another cpu is still walking the hlist. In such case the lookup may miss the element. Convert hlist to hlist_nulls to avoid such scenario. When bucket lock is taken there is no need to take such precautions, so only convert map_lookup and map_get_next to nulls. The race window is extremely small and only reproducible with explicit udelay() inside lookup_nulls_elem_raw() Similar to hlist add hlist_nulls_for_each_entry_safe() and hlist_nulls_entry_safe() helpers. Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements") Reported-by: Jonathan Perry <jonperry@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-09bpf: fix struct htab_elem layoutAlexei Starovoitov1-5/+20
when htab_elem is removed from the bucket list the htab_elem.hash_node.next field should not be overridden too early otherwise we have a tiny race window between lookup and delete. The bug was discovered by manual code analysis and reproducible only with explicit udelay() in lookup_elem_raw(). Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements") Reported-by: Jonathan Perry <jonperry@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-05bpf: add get_next_key callback to LPM mapAlexei Starovoitov1-0/+6
map_get_next_key callback is mandatory. Supply dummy handler. Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation") Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds1-1/+1
Pull networking fixes from David Miller: 1) Fix double-free in batman-adv, from Sven Eckelmann. 2) Fix packet stats for fast-RX path, from Joannes Berg. 3) Netfilter's ip_route_me_harder() doesn't handle request sockets properly, fix from Florian Westphal. 4) Fix sendmsg deadlock in rxrpc, from David Howells. 5) Add missing RCU locking to transport hashtable scan, from Xin Long. 6) Fix potential packet loss in mlxsw driver, from Ido Schimmel. 7) Fix race in NAPI handling between poll handlers and busy polling, from Eric Dumazet. 8) TX path in vxlan and geneve need proper RCU locking, from Jakub Kicinski. 9) SYN processing in DCCP and TCP need to disable BH, from Eric Dumazet. 10) Properly handle net_enable_timestamp() being invoked from IRQ context, also from Eric Dumazet. 11) Fix crash on device-tree systems in xgene driver, from Alban Bedel. 12) Do not call sk_free() on a locked socket, from Arnaldo Carvalho de Melo. 13) Fix use-after-free in netvsc driver, from Dexuan Cui. 14) Fix max MTU setting in bonding driver, from WANG Cong. 15) xen-netback hash table can be allocated from softirq context, so use GFP_ATOMIC. From Anoob Soman. 16) Fix MAC address change bug in bgmac driver, from Hari Vyas. 17) strparser needs to destroy strp_wq on module exit, from WANG Cong. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (69 commits) strparser: destroy workqueue on module exit sfc: fix IPID endianness in TSOv2 sfc: avoid max() in array size rds: remove unnecessary returned value check rxrpc: Fix potential NULL-pointer exception nfp: correct DMA direction in XDP DMA sync nfp: don't tell FW about the reserved buffer space net: ethernet: bgmac: mac address change bug net: ethernet: bgmac: init sequence bug xen-netback: don't vfree() queues under spinlock xen-netback: keep a local pointer for vif in backend_disconnect() netfilter: nf_tables: don't call nfnetlink_set_err() if nfnetlink_send() fails netfilter: nft_set_rbtree: incorrect assumption on lower interval lookups netfilter: nf_conntrack_sip: fix wrong memory initialisation can: flexcan: fix typo in comment can: usb_8dev: Fix memory leak of priv->cmd_msg_buffer can: gs_usb: fix coding style can: gs_usb: Don't use stack memory for USB transfers ixgbe: Limit use of 2K buffers on architectures with 256B or larger cache lines ixgbe: update the rss key on h/w, when ethtool ask for it ...
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar1-0/+1
<linux/sched/signal.h> We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-01bpf: update the comment about the length of analysisGary Lin1-1/+1
Commit 07016151a446 ("bpf, verifier: further improve search pruning") increased the limit of processed instructions from 32k to 64k, but the comment still mentioned the 32k limit. This commit updates the comment to reflect the change. Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Gary Lin <glin@suse.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-23bpf: fix spelling mistake: "proccessed" -> "processed"Colin Ian King1-1/+1
trivial fix to spelling mistake in verbose log message Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-17bpf: make jited programs visible in tracesDaniel Borkmann2-0/+225
Long standing issue with JITed programs is that stack traces from function tracing check whether a given address is kernel code through {__,}kernel_text_address(), which checks for code in core kernel, modules and dynamically allocated ftrace trampolines. But what is still missing is BPF JITed programs (interpreted programs are not an issue as __bpf_prog_run() will be attributed to them), thus when a stack trace is triggered, the code walking the stack won't see any of the JITed ones. The same for address correlation done from user space via reading /proc/kallsyms. This is read by tools like perf, but the latter is also useful for permanent live tracing with eBPF itself in combination with stack maps when other eBPF types are part of the callchain. See offwaketime example on dumping stack from a map. This work tries to tackle that issue by making the addresses and symbols known to the kernel. The lookup from *kernel_text_address() is implemented through a latched RB tree that can be read under RCU in fast-path that is also shared for symbol/size/offset lookup for a specific given address in kallsyms. The slow-path iteration through all symbols in the seq file done via RCU list, which holds a tiny fraction of all exported ksyms, usually below 0.1 percent. Function symbols are exported as bpf_prog_<tag>, in order to aide debugging and attribution. This facility is currently enabled for root-only when bpf_jit_kallsyms is set to 1, and disabled if hardening is active in any mode. The rationale behind this is that still a lot of systems ship with world read permissions on kallsyms thus addresses should not get suddenly exposed for them. If that situation gets much better in future, we always have the option to change the default on this. Likewise, unprivileged programs are not allowed to add entries there either, but that is less of a concern as most such programs types relevant in this context are for root-only anyway. If enabled, call graphs and stack traces will then show a correct attribution; one example is illustrated below, where the trace is now visible in tooling such as perf script --kallsyms=/proc/kallsyms and friends. Before: 7fff8166889d bpf_clone_redirect+0x80007f0020ed (/lib/modules/4.9.0-rc8+/build/vmlinux) f5d80 __sendmsg_nocancel+0xffff006451f1a007 (/usr/lib64/libc-2.18.so) After: 7fff816688b7 bpf_clone_redirect+0x80007f002107 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fffa0575728 bpf_prog_33c45a467c9e061a+0x8000600020fb (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fffa07ef1fc cls_bpf_classify+0x8000600020dc (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff81678b68 tc_classify+0x80007f002078 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164d40b __netif_receive_skb_core+0x80007f0025fb (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164d718 __netif_receive_skb+0x80007f002018 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164e565 process_backlog+0x80007f002095 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8164dc71 net_rx_action+0x80007f002231 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff81767461 __softirqentry_text_start+0x80007f0020d1 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff817658ac do_softirq_own_stack+0x80007f00201c (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff810a2c20 do_softirq+0x80007f002050 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff810a2cb5 __local_bh_enable_ip+0x80007f002085 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168d452 ip_finish_output2+0x80007f002152 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168ea3d ip_finish_output+0x80007f00217d (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff8168f2af ip_output+0x80007f00203f (/lib/modules/4.9.0-rc8+/build/vmlinux) [...] 7fff81005854 do_syscall_64+0x80007f002054 (/lib/modules/4.9.0-rc8+/build/vmlinux) 7fff817649eb return_from_SYSCALL_64+0x80007f002000 (/lib/modules/4.9.0-rc8+/build/vmlinux) f5d80 __sendmsg_nocancel+0xffff01c484812007 (/usr/lib64/libc-2.18.so) Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>