path: root/arch
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authorNumfor Mbiziwo-Tiapo <nums@google.com>2021-09-23 09:18:43 -0700
committerBorislav Petkov <bp@suse.de>2021-09-24 12:37:38 +0200
commit5ba1071f7554c4027bdbd712a146111de57918de (patch)
treea8b9d04fc9a87bdae3e91db1d9a42e3547f4b0c0 /arch
parentd81ff5fe14a950f53e2833cfa196e7bb3fd5d4e3 (diff)
x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses
Don't perform unaligned loads in __get_next() and __peek_nbyte_next() as these are forms of undefined behavior: "A pointer to an object or incomplete type may be converted to a pointer to a different object or incomplete type. If the resulting pointer is not correctly aligned for the pointed-to type, the behavior is undefined." (from http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf) These problems were identified using the undefined behavior sanitizer (ubsan) with the tools version of the code and perf test. [ bp: Massage commit message. ] Signed-off-by: Numfor Mbiziwo-Tiapo <nums@google.com> Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lkml.kernel.org/r/20210923161843.751834-1-irogers@google.com
Diffstat (limited to 'arch')
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 058f19b20465..c565def611e2 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -37,10 +37,10 @@
((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr)
#define __get_next(t, insn) \
- ({ t r = *(t*)insn->next_byte; insn->next_byte += sizeof(t); leXX_to_cpu(t, r); })
+ ({ t r; memcpy(&r, insn->next_byte, sizeof(t)); insn->next_byte += sizeof(t); leXX_to_cpu(t, r); })
#define __peek_nbyte_next(t, insn, n) \
- ({ t r = *(t*)((insn)->next_byte + n); leXX_to_cpu(t, r); })
+ ({ t r; memcpy(&r, (insn)->next_byte + n, sizeof(t)); leXX_to_cpu(t, r); })
#define get_next(t, insn) \
({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); })

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