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| author | Numfor Mbiziwo-Tiapo <nums@google.com> | 2021-09-23 18:18:43 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-09-24 12:37:38 +0200 |
| commit | 5ba1071f7554c4027bdbd712a146111de57918de (patch) | |
| tree | a8b9d04fc9a87bdae3e91db1d9a42e3547f4b0c0 | |
| parent | x86/asm: Fix SETZ size enqcmds() build failure (diff) | |
| download | linux-5ba1071f7554c4027bdbd712a146111de57918de.tar.xz linux-5ba1071f7554c4027bdbd712a146111de57918de.zip | |
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
| -rw-r--r-- | arch/x86/lib/insn.c | 4 | ||||
| -rw-r--r-- | tools/arch/x86/lib/insn.c | 4 |
2 files changed, 4 insertions, 4 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); }) diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c index c41f95815480..797699462cd8 100644 --- a/tools/arch/x86/lib/insn.c +++ b/tools/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); }) |