kernel/linux.git/include/linux/filter.h, branch v6.1.140

xdp: Reset bpf_redirect_info before running a xdp's BPF prog.

2025-05-02T05:47:09+00:00

Ricardo reported a KASAN discovered use after free in v6.6-stable. The syzbot starts a BPF program via xdp_test_run_batch() which assigns ri->tgt_value via dev_hash_map_redirect() and the return code isn't XDP_REDIRECT it looks like nonsense. So the output in bpf_warn_invalid_xdp_action() appears once. Then the TUN driver runs another BPF program (on the same CPU) which returns XDP_REDIRECT without setting ri->tgt_value first. It invokes bpf_trace_printk() to print four characters and obtain the required return value. This is enough to get xdp_do_redirect() invoked which then accesses the pointer in tgt_value which might have been already deallocated. This problem does not affect upstream because since commit 401cb7dae8130 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") the per-CPU variable is referenced via task's task_struct and exists on the stack during NAPI callback. Therefore it is cleared once before the first invocation and remains valid within the RCU section of the NAPI callback. Instead of performing the huge backport of the commit (plus its fix ups) here is an alternative version which only resets the variable in question prior invoking the BPF program. Acked-by: Toke Høiland-Jørgensen Reported-by: Ricardo Cañuelo Navarro Closes: https://lore.kernel.org/all/20250226-20250204-kasan-slab-use-after-free-read-in-dev_map_enqueue__submit-v3-0-360efec441ba@igalia.com/ Fixes: 97f91a7cf04ff ("bpf: add bpf_redirect_map helper routine") Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Greg Kroah-Hartman

bpf: Take return from set_memory_ro() into account with bpf_prog_lock_ro()

2024-07-05T07:31:47+00:00

[ Upstream commit 7d2cc63eca0c993c99d18893214abf8f85d566d8 ] set_memory_ro() can fail, leaving memory unprotected. Check its return and take it into account as an error. Link: https://github.com/KSPP/linux/issues/7 Signed-off-by: Christophe Leroy Cc: linux-hardening@vger.kernel.org Reviewed-by: Kees Cook Message-ID: <286def78955e04382b227cb3e4b6ba272a7442e3.1709850515.git.christophe.leroy@csgroup.eu> Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

bpf: Mark bpf_spin_{lock,unlock}() helpers with notrace correctly

2024-03-26T22:20:35+00:00

[ Upstream commit 178c54666f9c4d2f49f2ea661d0c11b52f0ed190 ] Currently tracing is supposed not to allow for bpf_spin_{lock,unlock}() helper calls. This is to prevent deadlock for the following cases: - there is a prog (prog-A) calling bpf_spin_{lock,unlock}(). - there is a tracing program (prog-B), e.g., fentry, attached to bpf_spin_lock() and/or bpf_spin_unlock(). - prog-B calls bpf_spin_{lock,unlock}(). For such a case, when prog-A calls bpf_spin_{lock,unlock}(), a deadlock will happen. The related source codes are below in kernel/bpf/helpers.c: notrace BPF_CALL_1(bpf_spin_lock, struct bpf_spin_lock *, lock) notrace BPF_CALL_1(bpf_spin_unlock, struct bpf_spin_lock *, lock) notrace is supposed to prevent fentry prog from attaching to bpf_spin_{lock,unlock}(). But actually this is not the case and fentry prog can successfully attached to bpf_spin_lock(). Siddharth Chintamaneni reported the issue in [1]. The following is the macro definition for above BPF_CALL_1: #define BPF_CALL_x(x, name, ...) \ static __always_inline \ u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \ typedef u64 (*btf_##name)(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \ u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)); \ u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)) \ { \ return ((btf_##name)____##name)(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\ } \ static __always_inline \ u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)) #define BPF_CALL_1(name, ...) BPF_CALL_x(1, name, __VA_ARGS__) The notrace attribute is actually applied to the static always_inline function ____bpf_spin_{lock,unlock}(). The actual callback function bpf_spin_{lock,unlock}() is not marked with notrace, hence allowing fentry prog to attach to two helpers, and this may cause the above mentioned deadlock. Siddharth Chintamaneni actually has a reproducer in [2]. To fix the issue, a new macro NOTRACE_BPF_CALL_1 is introduced which will add notrace attribute to the original function instead of the hidden always_inline function and this fixed the problem. [1] https://lore.kernel.org/bpf/CAE5sdEigPnoGrzN8WU7Tx-h-iFuMZgW06qp0KHWtpvoXxf1OAQ@mail.gmail.com/ [2] https://lore.kernel.org/bpf/CAE5sdEg6yUc_Jz50AnUXEEUh6O73yQ1Z6NV2srJnef0ZrQkZew@mail.gmail.com/ Fixes: d83525ca62cf ("bpf: introduce bpf_spin_lock") Signed-off-by: Yonghong Song Signed-off-by: Andrii Nakryiko Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20240207070102.335167-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin

bpf: use bpf_prog_pack for bpf_dispatcher

2022-09-27T03:40:43+00:00

Allocate bpf_dispatcher with bpf_prog_pack_alloc so that bpf_dispatcher can share pages with bpf programs. arch_prepare_bpf_dispatcher() is updated to provide a RW buffer as working area for arch code to write to. This also fixes CPA W^X warnning like: CPA refuse W^X violation: 8000000000000163 -> 0000000000000163 range: ... Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20220926184739.3512547-2-song@kernel.org Signed-off-by: Alexei Starovoitov

bpf: Move nf_conn extern declarations to filter.h

2022-09-20T21:41:35+00:00

We're seeing the following new warnings on netdev/build_32bit and netdev/build_allmodconfig_warn CI jobs: ../net/core/filter.c:8608:1: warning: symbol 'nf_conn_btf_access_lock' was not declared. Should it be static? ../net/core/filter.c:8611:5: warning: symbol 'nfct_bsa' was not declared. Should it be static? Fix by ensuring extern declaration is present while compiling filter.o. Fixes: 864b656f82cc ("bpf: Add support for writing to nf_conn:mark") Signed-off-by: Daniel Xu Link: https://lore.kernel.org/r/2bd2e0283df36d8a4119605878edb1838d144174.1663683114.git.dxu@dxuuu.xyz Signed-off-by: Martin KaFai Lau

bpf: Use bpf_capable() instead of CAP_SYS_ADMIN for blinding decision

2022-09-16T20:11:57+00:00

The full CAP_SYS_ADMIN requirement for blinding looks too strict nowadays. These days given unprivileged BPF is disabled by default, the main users for constant blinding coming from unprivileged in particular via cBPF -> eBPF migration (e.g. old-style socket filters). Signed-off-by: Yauheni Kaliuta Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220831090655.156434-1-ykaliuta@redhat.com Link: https://lore.kernel.org/bpf/20220905090149.61221-1-ykaliuta@redhat.com

bpf: net: Change sk_getsockopt() to take the sockptr_t argument

2022-09-03T03:34:30+00:00

This patch changes sk_getsockopt() to take the sockptr_t argument such that it can be used by bpf_getsockopt(SOL_SOCKET) in a latter patch. security_socket_getpeersec_stream() is not changed. It stays with the __user ptr (optval.user and optlen.user) to avoid changes to other security hooks. bpf_getsockopt(SOL_SOCKET) also does not support SO_PEERSEC. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20220902002802.2888419-1-kafai@fb.com Signed-off-by: Alexei Starovoitov

bpf, x86: fix freeing of not-finalized bpf_prog_pack

2022-07-13T00:33:22+00:00

syzbot reported a few issues with bpf_prog_pack [1], [2]. This only happens with multiple subprogs. In jit_subprogs(), we first call bpf_int_jit_compile() on each sub program. And then, we call it on each sub program again. jit_data is not freed in the first call of bpf_int_jit_compile(). Similarly we don't call bpf_jit_binary_pack_finalize() in the first call of bpf_int_jit_compile(). If bpf_int_jit_compile() failed for one sub program, we will call bpf_jit_binary_pack_finalize() for this sub program. However, we don't have a chance to call it for other sub programs. Then we will hit "goto out_free" in jit_subprogs(), and call bpf_jit_free on some subprograms that haven't got bpf_jit_binary_pack_finalize() yet. At this point, bpf_jit_binary_pack_free() is called and the whole 2MB page is freed erroneously. Fix this with a custom bpf_jit_free() for x86_64, which calls bpf_jit_binary_pack_finalize() if necessary. Also, with custom bpf_jit_free(), bpf_prog_aux->use_bpf_prog_pack is not needed any more, remove it. Fixes: 1022a5498f6f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc") [1] https://syzkaller.appspot.com/bug?extid=2f649ec6d2eea1495a8f [2] https://syzkaller.appspot.com/bug?extid=87f65c75f4a72db05445 Reported-by: syzbot+2f649ec6d2eea1495a8f@syzkaller.appspotmail.com Reported-by: syzbot+87f65c75f4a72db05445@syzkaller.appspotmail.com Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20220706002612.4013790-1-song@kernel.org Signed-off-by: Alexei Starovoitov

bpf, x64: Add predicate for bpf2bpf with tailcalls support in JIT

2022-06-21T16:52:04+00:00

The BPF core/verifier is hard-coded to permit mixing bpf2bpf and tail calls for only x86-64. Change the logic to instead rely on a new weak function 'bool bpf_jit_supports_subprog_tailcalls(void)', which a capable JIT backend can override. Update the x86-64 eBPF JIT to reflect this. Signed-off-by: Tony Ambardar [jakub: drop MIPS bits and tweak patch subject] Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220617105735.733938-2-jakub@cloudflare.com

bpf: move bpf_prog to bpf.h

2022-06-17T02:27:29+00:00

In order to add a version of bpf_prog_run_array which accesses the bpf_prog->aux member, bpf_prog needs to be more than a forward declaration inside bpf.h. Given that filter.h already includes bpf.h, this merely reorders the type declarations for filter.h users. bpf.h users now have access to bpf_prog internals. Signed-off-by: Delyan Kratunov Link: https://lore.kernel.org/r/3ed7824e3948f22d84583649ccac0ff0d38b6b58.1655248076.git.delyank@fb.com Signed-off-by: Alexei Starovoitov