linux/tools/lib/bpf, branch v5.12

libbpf: Fix potential NULL pointer dereference

2021-04-08T21:36:46Z

Wait until after the UMEM is checked for null to dereference it. Fixes: 43f1bc1efff1 ("libbpf: Restore umem state after socket create failure") Signed-off-by: Ciara Loftus Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210408052009.7844-1-ciara.loftus@intel.com

libbpf: Only create rx and tx XDP rings when necessary

2021-04-01T21:45:43Z

Prior to this commit xsk_socket__create(_shared) always attempted to create the rx and tx rings for the socket. However this causes an issue when the socket being setup is that which shares the fd with the UMEM. If a previous call to this function failed with this socket after the rings were set up, a subsequent call would always fail because the rings are not torn down after the first call and when we try to set them up again we encounter an error because they already exist. Solve this by remembering whether the rings were set up by introducing new bools to struct xsk_umem which represent the ring setup status and using them to determine whether or not to set up the rings. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Ciara Loftus Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210331061218.1647-4-ciara.loftus@intel.com

libbpf: Restore umem state after socket create failure

2021-04-01T21:45:43Z

If the call to xsk_socket__create fails, the user may want to retry the socket creation using the same umem. Ensure that the umem is in the same state on exit if the call fails by: 1. ensuring the umem _save pointers are unmodified. 2. not unmapping the set of umem rings that were set up with the umem during xsk_umem__create, since those maps existed before the call to xsk_socket__create and should remain in tact even in the event of failure. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Signed-off-by: Ciara Loftus Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210331061218.1647-3-ciara.loftus@intel.com

libbpf: Ensure umem pointer is non-NULL before dereferencing

2021-04-01T21:45:43Z

Calls to xsk_socket__create dereference the umem to access the fill_save and comp_save pointers. Make sure the umem is non-NULL before doing this. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Signed-off-by: Ciara Loftus Signed-off-by: Alexei Starovoitov Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20210331061218.1647-2-ciara.loftus@intel.com

libbpf: Fix bail out from 'ringbuf_process_ring()' on error

2021-03-26T04:13:24Z

The current code bails out with negative and positive returns. If the callback returns a positive return code, 'ring_buffer__consume()' and 'ring_buffer__poll()' will return a spurious number of records consumed, but mostly important will continue the processing loop. This patch makes positive returns from the callback a no-op. Fixes: bf99c936f947 ("libbpf: Add BPF ring buffer support") Signed-off-by: Pedro Tammela Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210325150115.138750-1-pctammela@mojatatu.com

libbpf: Fix BTF dump of pointer-to-array-of-struct

2021-03-19T21:14:44Z

The vmlinux.h generated from BTF is invalid when building drivers/phy/ti/phy-gmii-sel.c with clang: vmlinux.h:61702:27: error: array type has incomplete element type ‘struct reg_field’ 61702 | const struct reg_field (*regfields)[3]; | ^~~~~~~~~ bpftool generates a forward declaration for this struct regfield, which compilers aren't happy about. Here's a simplified reproducer: struct inner { int val; }; struct outer { struct inner (*ptr_to_array)[2]; } A; After build with clang -> bpftool btf dump c -> clang/gcc: ./def-clang.h:11:23: error: array has incomplete element type 'struct inner' struct inner (*ptr_to_array)[2]; Member ptr_to_array of struct outer is a pointer to an array of struct inner. In the DWARF generated by clang, struct outer appears before struct inner, so when converting BTF of struct outer into C, bpftool issues a forward declaration to struct inner. With GCC the DWARF info is reversed so struct inner gets fully defined. That forward declaration is not sufficient when compilers handle an array of the struct, even when it's only used through a pointer. Note that we can trigger the same issue with an intermediate typedef: struct inner { int val; }; typedef struct inner inner2_t[2]; struct outer { inner2_t *ptr_to_array; } A; Becomes: struct inner; typedef struct inner inner2_t[2]; And causes: ./def-clang.h:10:30: error: array has incomplete element type 'struct inner' typedef struct inner inner2_t[2]; To fix this, clear through_ptr whenever we encounter an intermediate array, to make the inner struct part of a strong link and force full declaration. Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion") Signed-off-by: Jean-Philippe Brucker Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210319112554.794552-2-jean-philippe@linaro.org

libbpf: Use SOCK_CLOEXEC when opening the netlink socket

2021-03-17T23:50:21Z

Otherwise, there exists a small window between the opening and closing of the socket fd where it may leak into processes launched by some other thread. Fixes: 949abbe88436 ("libbpf: add function to setup XDP") Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Daniel Borkmann Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/20210317115857.6536-1-memxor@gmail.com

libbpf: Fix error path in bpf_object__elf_init()

2021-03-17T23:42:21Z

When it failed to get section names, it should call into bpf_object__elf_finish() like others. Fixes: 88a82120282b ("libbpf: Factor out common ELF operations and improve logging") Signed-off-by: Namhyung Kim Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210317145414.884817-1-namhyung@kernel.org

libbpf: Fix INSTALL flag order

2021-03-08T18:43:27Z

It was reported ([0]) that having optional -m flag between source and destination arguments in install command breaks bpftools cross-build on MacOS. Move -m to the front to fix this issue. [0] https://github.com/openwrt/openwrt/pull/3959 Fixes: 7110d80d53f4 ("libbpf: Makefile set specified permission mode") Signed-off-by: Georgi Valkov Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210308183038.613432-1-andrii@kernel.org

libbpf: Clear map_info before each bpf_obj_get_info_by_fd

2021-03-04T14:53:37Z

xsk_lookup_bpf_maps, based on prog_fd, looks whether current prog has a reference to XSKMAP. BPF prog can include insns that work on various BPF maps and this is covered by iterating through map_ids. The bpf_map_info that is passed to bpf_obj_get_info_by_fd for filling needs to be cleared at each iteration, so that it doesn't contain any outdated fields and that is currently missing in the function of interest. To fix that, zero-init map_info via memset before each bpf_obj_get_info_by_fd call. Also, since the area of this code is touched, in general strcmp is considered harmful, so let's convert it to strncmp and provide the size of the array name for current map_info. While at it, do s/continue/break/ once we have found the xsks_map to terminate the search. Fixes: 5750902a6e9b ("libbpf: proper XSKMAP cleanup") Signed-off-by: Maciej Fijalkowski Signed-off-by: Daniel Borkmann Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20210303185636.18070-4-maciej.fijalkowski@intel.com