@@ -101,6 +101,8 @@ struct vdso_sym required_syms[] = {
{"__kernel_sigreturn", true},
{"__kernel_rt_sigreturn", true},
{"int80_landing_pad", true},
+ {"vdso32_rt_sigreturn_landing_pad", true},
+ {"vdso32_sigreturn_landing_pad", true},
};
__attribute__((format(printf, 1, 2))) __attribute__((noreturn))
@@ -18,6 +18,7 @@ __kernel_sigreturn:
movl $__NR_sigreturn, %eax
SYSCALL_ENTER_KERNEL
.LEND_sigreturn:
+SYM_INNER_LABEL(vdso32_sigreturn_landing_pad, SYM_L_GLOBAL)
nop
.size __kernel_sigreturn,.-.LSTART_sigreturn
@@ -29,6 +30,7 @@ __kernel_rt_sigreturn:
movl $__NR_rt_sigreturn, %eax
SYSCALL_ENTER_KERNEL
.LEND_rt_sigreturn:
+SYM_INNER_LABEL(vdso32_rt_sigreturn_landing_pad, SYM_L_GLOBAL)
nop
.size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn
.previous
@@ -436,6 +436,21 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
}
#endif
+int 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 1;
+ }
+#endif
+ return 0;
+}
+
#ifdef CONFIG_X86_64
static __init int vdso_setup(char *s)
{
@@ -385,6 +385,7 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp);
extern int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp);
+extern int arch_syscall_is_vdso_sigreturn(struct pt_regs *regs);
#define compat_arch_setup_additional_pages compat_arch_setup_additional_pages
/* Do not change the values. See get_align_mask() */
@@ -27,6 +27,8 @@ struct vdso_image {
long sym___kernel_rt_sigreturn;
long sym___kernel_vsyscall;
long sym_int80_landing_pad;
+ long sym_vdso32_sigreturn_landing_pad;
+ long sym_vdso32_rt_sigreturn_landing_pad;
};
#ifdef CONFIG_X86_64
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@amacapital.net> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> --- arch/x86/entry/vdso/vdso2c.c | 2 ++ arch/x86/entry/vdso/vdso32/sigreturn.S | 2 ++ arch/x86/entry/vdso/vma.c | 15 +++++++++++++++ arch/x86/include/asm/elf.h | 1 + arch/x86/include/asm/vdso.h | 2 ++ 5 files changed, 22 insertions(+)