From: Andreas Schwab <schwab@suse•de>
To: linuxppc-dev@ozlabs•org
Cc: linux-kernel@vger•kernel.org
Subject: [PATCH] Fix msr check in compat_sys_swapcontext
Date: Wed, 05 Nov 2008 13:30:57 +0100 [thread overview]
Message-ID: <jeprlabbi6.fsf@sykes.suse.de> (raw)
The new context may not be 16-byte aligned, so the real address of the
mcontext structure should be read from the uc_regs pointer instead of
directly using the (unaligned) uc_mcontext field.
Signed-off-by: Andreas Schwab <schwab@suse•de>
---
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index a6a4310..dc10720 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -941,9 +941,17 @@ 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. */
+ 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 Schwab, SuSE Labs, schwab@suse•de
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."
next reply other threads:[~2008-11-05 12:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-05 12:30 Andreas Schwab [this message]
2008-11-06 0:52 ` [PATCH] Fix msr check in compat_sys_swapcontext Paul Mackerras
2008-11-06 9:23 ` Andreas Schwab
2008-11-06 10:36 ` Paul Mackerras
2008-11-06 10:49 ` Andreas Schwab
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=jeprlabbi6.fsf@sykes.suse.de \
--to=schwab@suse$(echo .)de \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linuxppc-dev@ozlabs$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox