On Tue, Sep 10, 2019 at 03:40:44PM -0700, Sami Tolvanen wrote: > Define a weak function in COND_SYSCALL instead of a weak alias to > sys_ni_syscall, which has an incompatible type. This fixes indirect > call mismatches with Control-Flow Integrity (CFI) checking. > > Signed-off-by: Sami Tolvanen <[email protected]>
This looks correct to me, builds fine, and I asume has been tested, so FWIW: Acked-by: Mark Rutland <[email protected]> In looking at this, I came to the conclusion that we can drop the ifdeffery around our SYSCALL_DEFINE0(), COND_SYSCALL(), and SYS_NI(), which I evidently cargo-culted from x86 (where the ifdeffery is actually necessary). I can send a follow up for that. Thanks, Mark. > --- > arch/arm64/include/asm/syscall_wrapper.h | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/include/asm/syscall_wrapper.h > b/arch/arm64/include/asm/syscall_wrapper.h > index 507d0ee6bc69..06d880b3526c 100644 > --- a/arch/arm64/include/asm/syscall_wrapper.h > +++ b/arch/arm64/include/asm/syscall_wrapper.h > @@ -8,6 +8,8 @@ > #ifndef __ASM_SYSCALL_WRAPPER_H > #define __ASM_SYSCALL_WRAPPER_H > > +struct pt_regs; > + > #define SC_ARM64_REGS_TO_ARGS(x, ...) \ > __MAP(x,__SC_ARGS \ > ,,regs->regs[0],,regs->regs[1],,regs->regs[2] \ > @@ -35,8 +37,11 @@ > ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, ERRNO); > \ > asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs > *__unused) > > -#define COND_SYSCALL_COMPAT(name) \ > - cond_syscall(__arm64_compat_sys_##name); > +#define COND_SYSCALL_COMPAT(name) > \ > + asmlinkage long __weak __arm64_compat_sys_##name(const struct pt_regs > *regs) \ > + { > \ > + return sys_ni_syscall(); > \ > + } > > #define COMPAT_SYS_NI(name) \ > SYSCALL_ALIAS(__arm64_compat_sys_##name, sys_ni_posix_timers); > @@ -70,7 +75,11 @@ > #endif > > #ifndef COND_SYSCALL > -#define COND_SYSCALL(name) cond_syscall(__arm64_sys_##name) > +#define COND_SYSCALL(name) > \ > + asmlinkage long __weak __arm64_sys_##name(const struct pt_regs *regs) > \ > + { > \ > + return sys_ni_syscall(); > \ > + } > #endif > > #ifndef SYS_NI > -- > 2.23.0.162.g0b9fbb3734-goog >
