diff options
Diffstat (limited to 'arch/powerpc/kernel/signal_64.c')
| -rw-r--r-- | arch/powerpc/kernel/signal_64.c | 36 |
1 files changed, 32 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index 93ebfb6944b..5f9d2ef2e24 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -268,6 +268,13 @@ static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp) } /* + * Userspace code may pass a ucontext which doesn't include VSX added + * at the end. We need to check for this case. + */ +#define UCONTEXTSIZEWITHOUTVSX \ + (sizeof(struct ucontext) - 32*sizeof(long)) + +/* * Handle {get,set,swap}_context operations */ int sys_swapcontext(struct ucontext __user *old_ctx, @@ -276,13 +283,34 @@ int sys_swapcontext(struct ucontext __user *old_ctx, { unsigned char tmp; sigset_t set; + unsigned long new_msr = 0; - /* Context size is for future use. Right now, we only make sure - * we are passed something we understand + if (new_ctx && + __get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR])) + return -EFAULT; + /* + * Check that the context is not smaller than the original + * size (with VMX but without VSX) */ - if (ctx_size < sizeof(struct ucontext)) + if (ctx_size < UCONTEXTSIZEWITHOUTVSX) return -EINVAL; - + /* + * If the new context state sets the MSR VSX bits but + * it doesn't provide VSX state. + */ + if ((ctx_size < sizeof(struct ucontext)) && + (new_msr & MSR_VSX)) + return -EINVAL; +#ifdef CONFIG_VSX + /* + * If userspace doesn't provide enough room for VSX data, + * but current thread has used VSX, we don't have anywhere + * to store the full context back into. + */ + if ((ctx_size < sizeof(struct ucontext)) && + (current->thread.used_vsr && old_ctx)) + return -EINVAL; +#endif if (old_ctx != NULL) { if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx)) || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0) |