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| author |   Gabriel Krisman Bertazi <krisman@collabora.com> | 2020-11-27 14:32:32 -0500 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2020-12-02 10:32:16 +0100 |
| commit | c5c878125ad5aca199dfc10b1af4010165aaa596 (patch) | |
| tree | f389ef222bb9189a987d5d64bb924d5f241f792f /arch/x86/entry/vdso/vma.c | |
| parent | MAINTAINERS: Add entry for common entry code (diff) | |
| download | linux-dev-c5c878125ad5aca199dfc10b1af4010165aaa596.tar.xz linux-dev-c5c878125ad5aca199dfc10b1af4010165aaa596.zip | |
x86: vdso: Expose sigreturn address on vdso to the kernel
Syscall user redirection requires the signal trampoline code to not be
captured, in order to support returning with a locked selector while
avoiding recursion back into the signal handler. For ia-32, which has
the trampoline in the vDSO, expose the entry points to the kernel, such
that it can avoid dispatching syscalls from that region to userspace.
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20201127193238.821364-2-krisman@collabora.com
Diffstat (limited to 'arch/x86/entry/vdso/vma.c')
| -rw-r--r-- | arch/x86/entry/vdso/vma.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index 50e5d3a2e70a..de60cd37070b 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -436,6 +436,21 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) } #endif +bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs) +{ +#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) + const struct vdso_image *image = current->mm->context.vdso_image; + unsigned long vdso = (unsigned long) current->mm->context.vdso; + + if (in_ia32_syscall() && image == &vdso_image_32) { + if (regs->ip == vdso + image->sym_vdso32_sigreturn_landing_pad || + regs->ip == vdso + image->sym_vdso32_rt_sigreturn_landing_pad) + return true; + } +#endif + return false; +} + #ifdef CONFIG_X86_64 static __init int vdso_setup(char *s) { |