Daniel Borkmann 6ae08ae3de bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers ... The current bpf_probe_read() and bpf_probe_read_str() helpers are broken in that they assume they can be used for probing memory access for kernel space addresses /as well as/ user space addresses. However, plain use of probe_kernel_read() for both cases will attempt to always access kernel space address space given access is performed under KERNEL_DS and some archs in-fact have overlapping address spaces where a kernel pointer and user pointer would have the /same/ address value and therefore accessing application memory via bpf_probe_read{,_str}() would read garbage values. Lets fix BPF side by making use of recently added 3d7081822f ("uaccess: Add non-pagefault user-space read functions"). Unfortunately, the only way to fix this status quo is to add dedicated bpf_probe_read_{user,kernel}() and bpf_probe_read_{user,kernel}_str() helpers. The bpf_probe_read{,_str}() helpers are kept as-is to retain their current behavior. The two *_user() variants attempt the access always under USER_DS set, the two *_kernel() variants will -EFAULT when accessing user memory if the underlying architecture has non-overlapping address ranges, also avoiding throwing the kernel warning via 00c42373d3 ("x86-64: add warning for non-canonical user access address dereferences"). Fixes: a5e8c07059 ("bpf: add bpf_probe_read_str helper") Fixes: 2541517c32 ("tracing, perf: Implement BPF programs attached to kprobes") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/796ee46e948bc808d54891a1108435f8652c6ca4.1572649915.git.daniel@iogearbox.net		2019-11-02 12:39:12 -07:00
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asm	tools: Add missing stdio.h include to asm/bug.h header	2019-09-25 09:51:44 -03:00
asm-generic	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36	2019-05-24 17:27:11 +02:00
linux	augmented rbtree: rework the RB_DECLARE_CALLBACKS macro definition	2019-09-25 17:51:39 -07:00
nolibc	tool headers nolibc: add RISCV support	2019-05-08 15:48:43 +02:00
tools	tools: bpf: fix license for a compat header file	2018-09-19 23:49:58 +02:00
trace/events	tools/lib/lockdep: Remove private kernel headers	2017-06-05 09:28:14 +02:00
uapi	bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers	2019-11-02 12:39:12 -07:00