linux/kernel/trace/bpf_trace.c, branch v6.8

Revert BPF token-related functionality

2023-12-19T16:23:03Z

This patch includes the following revert (one conflicting BPF FS patch and three token patch sets, represented by merge commits): - revert 0f5d5454c723 "Merge branch 'bpf-fs-mount-options-parsing-follow-ups'"; - revert 750e785796bb "bpf: Support uid and gid when mounting bpffs"; - revert 733763285acf "Merge branch 'bpf-token-support-in-libbpf-s-bpf-object'"; - revert c35919dcce28 "Merge branch 'bpf-token-and-bpf-fs-based-delegation'". Link: https://lore.kernel.org/bpf/CAHk-=wg7JuFYwGy=GOMbRCtOL+jwSQsdUaBsRWkDVYbxipbM5A@mail.gmail.com Signed-off-by: Andrii Nakryiko

bpf: Fail uprobe multi link with negative offset

2023-12-18T17:51:30Z

Currently the __uprobe_register will return 0 (success) when called with negative offset. The reason is that the call to register_for_each_vma and then build_map_info won't return error for negative offset. They just won't do anything - no matching vma is found so there's no registered breakpoint for the uprobe. I don't think we can change the behaviour of __uprobe_register and fail for negative uprobe offset, because apps might depend on that already. But I think we can still make the change and check for it on bpf multi link syscall level. Also moving the __get_user call and check for the offsets to the top of loop, to fail early without extra __get_user calls for ref_ctr_offset and cookie arrays. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20231217215538.3361991-2-jolsa@kernel.org

bpf: Limit the number of kprobes when attaching program to multiple kprobes

2023-12-15T21:54:55Z

An abnormally big cnt may also be assigned to kprobe_multi.cnt when attaching multiple kprobes. It will trigger the following warning in kvmalloc_node(): if (unlikely(size > INT_MAX)) { WARN_ON_ONCE(!(flags & __GFP_NOWARN)); return NULL; } Fix the warning by limiting the maximal number of kprobes in bpf_kprobe_multi_link_attach(). If the number of kprobes is greater than MAX_KPROBE_MULTI_CNT, the attachment will fail and return -E2BIG. Fixes: 0dcac2725406 ("bpf: Add multi kprobe link") Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20231215100708.2265609-3-houtao@huaweicloud.com

bpf: Limit the number of uprobes when attaching program to multiple uprobes

2023-12-15T21:54:46Z

An abnormally big cnt may be passed to link_create.uprobe_multi.cnt, and it will trigger the following warning in kvmalloc_node(): if (unlikely(size > INT_MAX)) { WARN_ON_ONCE(!(flags & __GFP_NOWARN)); return NULL; } Fix the warning by limiting the maximal number of uprobes in bpf_uprobe_multi_link_attach(). If the number of uprobes is greater than MAX_UPROBE_MULTI_CNT, the attachment will return -E2BIG. Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link") Reported-by: Xingwei Lee Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Acked-by: Andrii Nakryiko Closes: https://lore.kernel.org/bpf/CABOYnLwwJY=yFAGie59LFsUsBAgHfroVqbzZ5edAXbFE3YiNVA@mail.gmail.com Link: https://lore.kernel.org/bpf/20231215100708.2265609-2-houtao@huaweicloud.com

bpf: take into account BPF token when fetching helper protos

2023-12-06T18:02:59Z

Instead of performing unconditional system-wide bpf_capable() and perfmon_capable() calls inside bpf_base_func_proto() function (and other similar ones) to determine eligibility of a given BPF helper for a given program, use previously recorded BPF token during BPF_PROG_LOAD command handling to inform the decision. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20231130185229.2688956-8-andrii@kernel.org Signed-off-by: Alexei Starovoitov

bpf: Add kfunc bpf_get_file_xattr

2023-12-02T00:21:03Z

It is common practice for security solutions to store tags/labels in xattrs. To implement similar functionalities in BPF LSM, add new kfunc bpf_get_file_xattr(). The first use case of bpf_get_file_xattr() is to implement file verifications with asymmetric keys. Specificially, security applications could use fsverity for file hashes and use xattr to store file signatures. (kfunc for fsverity hash will be added in a separate commit.) Currently, only xattrs with "user." prefix can be read with kfunc bpf_get_file_xattr(). As use cases evolve, we may add a dedicated prefix for bpf_get_file_xattr(). To avoid recursion, bpf_get_file_xattr can be only called from LSM hooks. Signed-off-by: Song Liu Acked-by: Christian Brauner Acked-by: KP Singh Link: https://lore.kernel.org/r/20231129234417.856536-2-song@kernel.org Signed-off-by: Alexei Starovoitov

bpf: Add link_info support for uprobe multi link

2023-11-29T05:50:09Z

Adding support to get uprobe_link details through bpf_link_info interface. Adding new struct uprobe_multi to struct bpf_link_info to carry the uprobe_multi link details. The uprobe_multi.count is passed from user space to denote size of array fields (offsets/ref_ctr_offsets/cookies). The actual array size is stored back to uprobe_multi.count (allowing user to find out the actual array size) and array fields are populated up to the user passed size. All the non-array fields (path/count/flags/pid) are always set. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20231125193130.834322-4-jolsa@kernel.org

bpf: Store ref_ctr_offsets values in bpf_uprobe array

2023-11-29T05:50:09Z

We will need to return ref_ctr_offsets values through link_info interface in following change, so we need to keep them around. Storing ref_ctr_offsets values directly into bpf_uprobe array. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20231125193130.834322-3-jolsa@kernel.org

bpf: Add __bpf_dynptr_data* for in kernel use

2023-11-10T03:07:38Z

Different types of bpf dynptr have different internal data storage. Specifically, SKB and XDP type of dynptr may have non-continuous data. Therefore, it is not always safe to directly access dynptr->data. Add __bpf_dynptr_data and __bpf_dynptr_data_rw to replace direct access to dynptr->data. Update bpf_verify_pkcs7_signature to use __bpf_dynptr_data instead of dynptr->data. Signed-off-by: Song Liu Signed-off-by: Andrii Nakryiko Acked-by: Vadim Fedorenko Link: https://lore.kernel.org/bpf/20231107045725.2278852-2-song@kernel.org Signed-off-by: Alexei Starovoitov

bpf: Add __bpf_kfunc_{start,end}_defs macros

2023-11-02T05:33:53Z

BPF kfuncs are meant to be called from BPF programs. Accordingly, most kfuncs are not called from anywhere in the kernel, which the -Wmissing-prototypes warning is unhappy about. We've peppered __diag_ignore_all("-Wmissing-prototypes", ... everywhere kfuncs are defined in the codebase to suppress this warning. This patch adds two macros meant to bound one or many kfunc definitions. All existing kfunc definitions which use these __diag calls to suppress -Wmissing-prototypes are migrated to use the newly-introduced macros. A new __diag_ignore_all - for "-Wmissing-declarations" - is added to the __bpf_kfunc_start_defs macro based on feedback from Andrii on an earlier version of this patch [0] and another recent mailing list thread [1]. In the future we might need to ignore different warnings or do other kfunc-specific things. This change will make it easier to make such modifications for all kfunc defs. [0]: https://lore.kernel.org/bpf/CAEf4BzaE5dRWtK6RPLnjTW-MW9sx9K3Fn6uwqCTChK2Dcb1Xig@mail.gmail.com/ [1]: https://lore.kernel.org/bpf/ZT+2qCc%2FaXep0%2FLf@krava/ Signed-off-by: Dave Marchevsky Suggested-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Cc: Jiri Olsa Acked-by: Jiri Olsa Acked-by: David Vernet Acked-by: Yafang Shao Link: https://lore.kernel.org/r/20231031215625.2343848-1-davemarchevsky@fb.com Signed-off-by: Alexei Starovoitov