Messages in this thread Patch in this message | | | From | Dmitry Safonov <> | Subject | [PATCH v3 15/23] x86/signal: Check if vdso_image_32 is mapped before trying to land on it | Date | Fri, 11 Jun 2021 19:02:34 +0100 |
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Provide current_has_vdso(image) helper and check it apriory landing attempt on vdso vma. The helper is a macro, not a static inline funciton to avoid linux/sched/task_stack.h inclusion in asm/vdso.h.
Signed-off-by: Dmitry Safonov <dima@arista.com> --- arch/x86/entry/common.c | 10 +++++++++- arch/x86/ia32/ia32_signal.c | 4 ++-- arch/x86/include/asm/vdso.h | 4 ++++ arch/x86/kernel/signal.c | 4 ++-- 4 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 7b2542b13ebd..385a1c4bf4c0 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -150,11 +150,19 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs) /* Returns 0 to return using IRET or 1 to return using SYSEXIT/SYSRETL. */ __visible noinstr long do_fast_syscall_32(struct pt_regs *regs) { + unsigned long landing_pad; + + if (!current_has_vdso(&vdso_image_32)) { + regs->ip = 0; + force_sigsegv(SIGSEGV); + syscall_exit_to_user_mode(regs); + } + /* * Called using the internal vDSO SYSENTER/SYSCALL32 calling * convention. Adjust regs so it looks like we entered using int80. */ - unsigned long landing_pad = (unsigned long)current->mm->context.vdso + + landing_pad = (unsigned long)current->mm->context.vdso + vdso_image_32.sym_int80_landing_pad; /* diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index adb6994c40f6..2af40ae53a0e 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -255,7 +255,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, restorer = ksig->ka.sa.sa_restorer; } else { /* Return stub is in 32bit vsyscall page */ - if (current->mm->context.vdso) + if (current_has_vdso(&vdso_image_32)) restorer = current->mm->context.vdso + vdso_image_32.sym___kernel_sigreturn; else @@ -336,7 +336,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, if (ksig->ka.sa.sa_flags & SA_RESTORER) restorer = ksig->ka.sa.sa_restorer; - else if (current->mm->context.vdso) + else if (current_has_vdso(&vdso_image_32)) restorer = current->mm->context.vdso + vdso_image_32.sym___kernel_rt_sigreturn; else diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index 98aa103eb4ab..1ea7cb3f9b14 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -45,6 +45,10 @@ extern const struct vdso_image vdso_image_x32; extern const struct vdso_image vdso_image_32; #endif +#define current_has_vdso(image) \ + (current->mm->context.vdso != 0 && \ + current->mm->context.vdso_image == image) + extern void __init init_vdso_image(const struct vdso_image *image); extern int map_vdso_once(const struct vdso_image *image, unsigned long addr); diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 988cbc634949..77496ccb812d 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -319,7 +319,7 @@ __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, unsafe_put_user(set->sig[1], &frame->extramask[0], Efault); if (ksig->ka.sa.sa_flags & SA_RESTORER) restorer = ksig->ka.sa.sa_restorer; - else if (current->mm->context.vdso) + else if (current_has_vdso(&vdso_image_32)) restorer = current->mm->context.vdso + vdso_image_32.sym___kernel_sigreturn; else @@ -381,7 +381,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, /* Set up to return from userspace. */ if (ksig->ka.sa.sa_flags & SA_RESTORER) restorer = ksig->ka.sa.sa_restorer; - else if (current->mm->context.vdso) + else if (current_has_vdso(&vdso_image_32)) restorer = current->mm->context.vdso + vdso_image_32.sym___kernel_rt_sigreturn; else -- 2.31.1
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