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| author | Kees Cook <keescook@chromium.org> | 2020-09-12 14:08:16 +0300 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2020-09-19 11:00:03 +0300 |
| commit | f04cf78bbfcd1fa5b1819613a5f354b228f36e03 (patch) | |
| tree | 870931840bba40a7f96821e2767f41288b6b812e | |
| parent | e4e8e5d28d5e1dac24f775452d4cc6f49f5c069e (diff) | |
| download | linux-f04cf78bbfcd1fa5b1819613a5f354b228f36e03.tar.xz | |
selftests/seccomp: Remove SYSCALL_NUM_RET_SHARE_REG in favor of SYSCALL_RET_SET
Instead of special-casing the specific case of shared registers, create
a default SYSCALL_RET_SET() macro (mirroring SYSCALL_NUM_SET()), that
writes to the SYSCALL_RET register. For architectures that can't set the
return value (for whatever reason), they can define SYSCALL_RET_SET()
without an associated SYSCALL_RET() macro. This also paves the way for
architectures that need to do special things to set the return value
(e.g. powerpc).
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/lkml/20200912110820.597135-12-keescook@chromium.org
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
| -rw-r--r-- | tools/testing/selftests/seccomp/seccomp_bpf.c | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 638cea8cb23d..84766a001ed0 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -1753,8 +1753,8 @@ TEST_F(TRACE_poke, getpid_runs_normally) #elif defined(__s390__) # define ARCH_REGS s390_regs # define SYSCALL_NUM(_regs) (_regs).gprs[2] -# define SYSCALL_RET(_regs) (_regs).gprs[2] -# define SYSCALL_NUM_RET_SHARE_REG +# define SYSCALL_RET_SET(_regs, _val) \ + TH_LOG("Can't modify syscall return on this architecture") #elif defined(__mips__) # include <asm/unistd_nr_n32.h> # include <asm/unistd_nr_n64.h> @@ -1776,8 +1776,8 @@ TEST_F(TRACE_poke, getpid_runs_normally) else \ (_regs).regs[2] = _nr; \ } while (0) -# define SYSCALL_RET(_regs) (_regs).regs[2] -# define SYSCALL_NUM_RET_SHARE_REG +# define SYSCALL_RET_SET(_regs, _val) \ + TH_LOG("Can't modify syscall return on this architecture") #elif defined(__xtensa__) # define ARCH_REGS struct user_pt_regs # define SYSCALL_NUM(_regs) (_regs).syscall @@ -1804,9 +1804,26 @@ TEST_F(TRACE_poke, getpid_runs_normally) SYSCALL_NUM(_regs) = (_nr); \ } while (0) #endif +/* + * Most architectures can change the syscall return value by just + * writing to the SYSCALL_RET register. This is the default if not + * defined above. If an architecture cannot set the return value + * (for example when the syscall and return value register is + * shared), report it with TH_LOG() in an arch-specific definition + * of SYSCALL_RET_SET() above, and leave SYSCALL_RET undefined. + */ +#if !defined(SYSCALL_RET) && !defined(SYSCALL_RET_SET) +# error "One of SYSCALL_RET or SYSCALL_RET_SET is needed for this arch" +#endif +#ifndef SYSCALL_RET_SET +# define SYSCALL_RET_SET(_regs, _val) \ + do { \ + SYSCALL_RET(_regs) = (_val); \ + } while (0) +#endif /* When the syscall return can't be changed, stub out the tests for it. */ -#ifdef SYSCALL_NUM_RET_SHARE_REG +#ifndef SYSCALL_RET # define EXPECT_SYSCALL_RETURN(val, action) EXPECT_EQ(-1, action) #else # define EXPECT_SYSCALL_RETURN(val, action) \ @@ -1870,11 +1887,7 @@ void change_syscall(struct __test_metadata *_metadata, /* If syscall is skipped, change return value. */ if (syscall == -1) -#ifdef SYSCALL_NUM_RET_SHARE_REG - TH_LOG("Can't modify syscall return on this architecture"); -#else - SYSCALL_RET(regs) = result; -#endif + SYSCALL_RET_SET(regs, result); /* Flush any register changes made. */ if (memcmp(&orig, ®s, sizeof(orig)) != 0) |