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authorChristoph Hellwig <hch@lst.de>2020-06-08 21:34:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-09 09:39:15 -0700
commit98a23609b10364a51a1bb3688f8dd1cd1aa94a9a (patch)
tree8cf32f92fccd8cd5264434d42fa68dcba4c2ab3c /kernel
parent7676fbf21b5fa04341c8046c2cbcd1949293e7ec (diff)
maccess: always use strict semantics for probe_kernel_read
Except for historical confusion in the kprobes/uprobes and bpf tracers, which has been fixed now, there is no good reason to ever allow user memory accesses from probe_kernel_read. Switch probe_kernel_read to only read from kernel memory. [akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200521152301.2587579-17-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/bpf_trace.c2
-rw-r--r--kernel/trace/trace_kprobe.c4
2 files changed, 3 insertions, 3 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 59cb19888891..e729c9e587a0 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -196,7 +196,7 @@ bpf_probe_read_kernel_common(void *dst, u32 size, const void *unsafe_ptr)
if (unlikely(ret < 0))
goto fail;
- ret = probe_kernel_read_strict(dst, unsafe_ptr, size);
+ ret = probe_kernel_read(dst, unsafe_ptr, size);
if (unlikely(ret < 0))
goto fail;
return ret;
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 6a23b45613a2..ea8d0b094f1b 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1222,7 +1222,7 @@ fetch_store_strlen(unsigned long addr)
#endif
do {
- ret = probe_kernel_read_strict(&c, (u8 *)addr + len, 1);
+ ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
len++;
} while (c && ret == 0 && len < MAX_STRING_SIZE);
@@ -1300,7 +1300,7 @@ probe_mem_read(void *dest, void *src, size_t size)
if ((unsigned long)src < TASK_SIZE)
return probe_mem_read_user(dest, src, size);
#endif
- return probe_kernel_read_strict(dest, src, size);
+ return probe_kernel_read(dest, src, size);
}
/* Note that we don't verify it, since the code does not come from user space */