| Message ID | 1546539240-20647-3-git-send-email-will.deacon@arm.com |
|---|---|
| State | Accepted |
| Commit | 53290432145a8eb143fe29e06e9c1465d43dc723 |
| Headers | show |
| Series | [1/3] arm64: compat: Avoid sending SIGILL for unallocated syscall numbers | expand |
On Thu, Jan 03, 2019 at 06:13:59PM +0000, Will Deacon wrote: > The syscall number may have been changed by a tracer, so we should pass > the actual number in from the caller instead of pulling it from the > saved r7 value directly. Reviewed-by: Dave Martin <Dave.Martin@arm.com> I was confused by the history here: commit 4141c857fd09 ("arm64: convert raw syscall invocation to C") breaks syscall changing via discarding the return from syscall_trace_enter() (which would also break this case for compat), but the subsequent patch that migrates the syscall code to C appears to fix it again. > > Cc: <stable@vger.kernel.org> > Cc: Dave Martin <Dave.Martin@arm.com> > Cc: Pi-Hsun Shih <pihsun@chromium.org> > Signed-off-by: Will Deacon <will.deacon@arm.com> > --- > arch/arm64/kernel/sys_compat.c | 9 ++++----- > arch/arm64/kernel/syscall.c | 9 ++++----- > 2 files changed, 8 insertions(+), 10 deletions(-) > > diff --git a/arch/arm64/kernel/sys_compat.c b/arch/arm64/kernel/sys_compat.c > index 5972b7533fa0..54c29cd38ff9 100644 > --- a/arch/arm64/kernel/sys_compat.c > +++ b/arch/arm64/kernel/sys_compat.c > @@ -66,12 +66,11 @@ do_compat_cache_op(unsigned long start, unsigned long end, int flags) > /* > * Handle all unrecognised system calls. > */ > -long compat_arm_syscall(struct pt_regs *regs) > +long compat_arm_syscall(struct pt_regs *regs, int scno) > { > - unsigned int no = regs->regs[7]; > void __user *addr; > > - switch (no) { > + switch (scno) { > /* > * Flush a region from virtual address 'r0' to virtual address 'r1' > * _exclusive_. There is no alignment requirement on either address; > @@ -107,7 +106,7 @@ long compat_arm_syscall(struct pt_regs *regs) > * way the calling program can gracefully determine whether > * a feature is supported. > */ > - if (no < __ARM_NR_compat_syscall_end) > + if (scno < __ARM_NR_compat_syscall_end) > return -ENOSYS; > break; > } > @@ -116,6 +115,6 @@ long compat_arm_syscall(struct pt_regs *regs) > (compat_thumb_mode(regs) ? 2 : 4); > > arm64_notify_die("Oops - bad compat syscall(2)", regs, > - SIGILL, ILL_ILLTRP, addr, no); > + SIGILL, ILL_ILLTRP, addr, scno); > return 0; > } > diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c > index 032d22312881..5610ac01c1ec 100644 > --- a/arch/arm64/kernel/syscall.c > +++ b/arch/arm64/kernel/syscall.c > @@ -13,16 +13,15 @@ > #include <asm/thread_info.h> > #include <asm/unistd.h> > > -long compat_arm_syscall(struct pt_regs *regs); > - > +long compat_arm_syscall(struct pt_regs *regs, int scno); > long sys_ni_syscall(void); > > -asmlinkage long do_ni_syscall(struct pt_regs *regs) > +static long do_ni_syscall(struct pt_regs *regs, int scno) > { > #ifdef CONFIG_COMPAT > long ret; > if (is_compat_task()) { > - ret = compat_arm_syscall(regs); > + ret = compat_arm_syscall(regs, scno); > if (ret != -ENOSYS) > return ret; > } > @@ -47,7 +46,7 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, > syscall_fn = syscall_table[array_index_nospec(scno, sc_nr)]; > ret = __invoke_syscall(regs, syscall_fn); > } else { > - ret = do_ni_syscall(regs); > + ret = do_ni_syscall(regs, scno); > } > > regs->regs[0] = ret; > -- > 2.1.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/kernel/sys_compat.c b/arch/arm64/kernel/sys_compat.c index 5972b7533fa0..54c29cd38ff9 100644 --- a/arch/arm64/kernel/sys_compat.c +++ b/arch/arm64/kernel/sys_compat.c @@ -66,12 +66,11 @@ do_compat_cache_op(unsigned long start, unsigned long end, int flags) /* * Handle all unrecognised system calls. */ -long compat_arm_syscall(struct pt_regs *regs) +long compat_arm_syscall(struct pt_regs *regs, int scno) { - unsigned int no = regs->regs[7]; void __user *addr; - switch (no) { + switch (scno) { /* * Flush a region from virtual address 'r0' to virtual address 'r1' * _exclusive_. There is no alignment requirement on either address; @@ -107,7 +106,7 @@ long compat_arm_syscall(struct pt_regs *regs) * way the calling program can gracefully determine whether * a feature is supported. */ - if (no < __ARM_NR_compat_syscall_end) + if (scno < __ARM_NR_compat_syscall_end) return -ENOSYS; break; } @@ -116,6 +115,6 @@ long compat_arm_syscall(struct pt_regs *regs) (compat_thumb_mode(regs) ? 2 : 4); arm64_notify_die("Oops - bad compat syscall(2)", regs, - SIGILL, ILL_ILLTRP, addr, no); + SIGILL, ILL_ILLTRP, addr, scno); return 0; } diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 032d22312881..5610ac01c1ec 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -13,16 +13,15 @@ #include <asm/thread_info.h> #include <asm/unistd.h> -long compat_arm_syscall(struct pt_regs *regs); - +long compat_arm_syscall(struct pt_regs *regs, int scno); long sys_ni_syscall(void); -asmlinkage long do_ni_syscall(struct pt_regs *regs) +static long do_ni_syscall(struct pt_regs *regs, int scno) { #ifdef CONFIG_COMPAT long ret; if (is_compat_task()) { - ret = compat_arm_syscall(regs); + ret = compat_arm_syscall(regs, scno); if (ret != -ENOSYS) return ret; } @@ -47,7 +46,7 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, syscall_fn = syscall_table[array_index_nospec(scno, sc_nr)]; ret = __invoke_syscall(regs, syscall_fn); } else { - ret = do_ni_syscall(regs); + ret = do_ni_syscall(regs, scno); } regs->regs[0] = ret;
The syscall number may have been changed by a tracer, so we should pass the actual number in from the caller instead of pulling it from the saved r7 value directly. Cc: <stable@vger.kernel.org> Cc: Dave Martin <Dave.Martin@arm.com> Cc: Pi-Hsun Shih <pihsun@chromium.org> Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/arm64/kernel/sys_compat.c | 9 ++++----- arch/arm64/kernel/syscall.c | 9 ++++----- 2 files changed, 8 insertions(+), 10 deletions(-) -- 2.1.4