6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Olsa <jolsa@xxxxxxxxxx> [ Upstream commit 1713b63a07a28a475de94664f783b4cfd2e4fa90 ] Currently the application with enabled shadow stack will crash if it sets up return uprobe. The reason is the uretprobe kernel code changes the user space task's stack, but does not update shadow stack accordingly. Adding new functions to update values on shadow stack and using them in uprobe code to keep shadow stack in sync with uretprobe changes to user stack. Link: https://lore.kernel.org/all/20240611112158.40795-2-jolsa@xxxxxxxxxx/ Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Acked-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx> Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx> Fixes: 488af8ea7131 ("x86/shstk: Wire in shadow stack interface") Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/x86/include/asm/shstk.h | 2 ++ arch/x86/kernel/shstk.c | 11 +++++++++++ arch/x86/kernel/uprobes.c | 7 ++++++- 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/shstk.h b/arch/x86/include/asm/shstk.h index 42fee8959df7b..896909f306e30 100644 --- a/arch/x86/include/asm/shstk.h +++ b/arch/x86/include/asm/shstk.h @@ -21,6 +21,7 @@ unsigned long shstk_alloc_thread_stack(struct task_struct *p, unsigned long clon void shstk_free(struct task_struct *p); int setup_signal_shadow_stack(struct ksignal *ksig); int restore_signal_shadow_stack(void); +int shstk_update_last_frame(unsigned long val); #else static inline long shstk_prctl(struct task_struct *task, int option, unsigned long arg2) { return -EINVAL; } @@ -31,6 +32,7 @@ static inline unsigned long shstk_alloc_thread_stack(struct task_struct *p, static inline void shstk_free(struct task_struct *p) {} static inline int setup_signal_shadow_stack(struct ksignal *ksig) { return 0; } static inline int restore_signal_shadow_stack(void) { return 0; } +static inline int shstk_update_last_frame(unsigned long val) { return 0; } #endif /* CONFIG_X86_USER_SHADOW_STACK */ #endif /* __ASSEMBLY__ */ diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c index 59e15dd8d0f86..19e4db582fb69 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -577,3 +577,14 @@ long shstk_prctl(struct task_struct *task, int option, unsigned long arg2) return wrss_control(true); return -EINVAL; } + +int shstk_update_last_frame(unsigned long val) +{ + unsigned long ssp; + + if (!features_enabled(ARCH_SHSTK_SHSTK)) + return 0; + + ssp = get_user_shstk_addr(); + return write_user_shstk_64((u64 __user *)ssp, (u64)val); +} diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 6c07f6daaa227..6402fb3089d26 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -1076,8 +1076,13 @@ arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs return orig_ret_vaddr; nleft = copy_to_user((void __user *)regs->sp, &trampoline_vaddr, rasize); - if (likely(!nleft)) + if (likely(!nleft)) { + if (shstk_update_last_frame(trampoline_vaddr)) { + force_sig(SIGSEGV); + return -1; + } return orig_ret_vaddr; + } if (nleft != rasize) { pr_err("return address clobbered: pid=%d, %%sp=%#lx, %%ip=%#lx\n", -- 2.43.0
