diff options
Diffstat (limited to 'arch/powerpc/kernel/signal_32.c')
| -rw-r--r-- | arch/powerpc/kernel/signal_32.c | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 9991e2a58bf..6f6810db0a7 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -68,6 +68,13 @@ #define ucontext ucontext32 /* + * 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) - sizeof(elf_vsrreghalf_t32)) + +/* * Returning 0 means we return to userspace via * ret_from_except and thus restore all user * registers from *regs. This is what we need @@ -930,12 +937,42 @@ long sys_swapcontext(struct ucontext __user *old_ctx, { unsigned char tmp; +#ifdef CONFIG_PPC64 + unsigned long new_msr = 0; + + if (new_ctx && + __get_user(new_msr, &new_ctx->uc_mcontext.mc_gregs[PT_MSR])) + return -EFAULT; + /* + * Check that the context is not smaller than the original + * size (with VMX but without VSX) + */ + 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 +#else /* Context size is for future use. Right now, we only make sure * we are passed something we understand */ if (ctx_size < sizeof(struct ucontext)) return -EINVAL; - +#endif if (old_ctx != NULL) { struct mcontext __user *mctx; |