Paul Mackerras <[EMAIL PROTECTED]> writes: > Andreas Schwab writes: > >> Paul Mackerras <[EMAIL PROTECTED]> writes: >> >> > we need to use get_user, not __get_user, since we haven't done an >> > access_ok() check on the address. >> >> The address is always ok since its a compat pointer, see do_setcontext. > > OK, since it's inside a CONFIG_PPC64 block. I'll add a paragraph to > the patch description pointing that out.
How about this: diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index a6a4310..b13abf3 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -941,9 +941,21 @@ long sys_swapcontext(struct ucontext __user *old_ctx, #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; + if (new_ctx) { + struct mcontext __user *mcp; + u32 cmcp; + + /* + * Get pointer to the real mcontext. No need for + * access_ok since we are dealing with compat + * pointers. + */ + if (__get_user(cmcp, &new_ctx->uc_regs)) + return -EFAULT; + mcp = (struct mcontext __user *)(u64)cmcp; + if (__get_user(new_msr, &mcp->mc_gregs[PT_MSR])) + return -EFAULT; + } /* * Check that the context is not smaller than the original * size (with VMX but without VSX) Andreas. -- Andreas Schwab, SuSE Labs, [EMAIL PROTECTED] SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev