Messages in this thread Patch in this message | | | Date | Wed, 03 Oct 2007 17:06:24 +0900 | From | Shi Weihua <> | Subject | [PATCH 1/3] signal(i386): alternative signal stack wraparound occurs |
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Fixing alternative signal stack wraparound.
If a process uses alternative signal stack by using sigaltstack() and that stack overflow, stack wraparound occurs. This patch checks whether the signal frame is on the alternative stack. If the frame is not on there, kill a signal SIGSEGV to the process forcedly then the process will be terminated.
This patch is for i386,version is 2.6.23-rc8.
Signed-off-by: Shi Weihua <shiwh@cn.fujitsu.com>
diff -pur linux-2.6.23-rc8.orig/arch/i386/kernel/signal.c linux-2.6.23-rc8/arch/i386/kernel/signal.c --- linux-2.6.23-rc8.orig/arch/i386/kernel/signal.c 2007-09-26 09:44:08.000000000 +0900 +++ linux-2.6.23-rc8/arch/i386/kernel/signal.c 2007-09-26 13:14:25.000000000 +0900 @@ -332,6 +332,10 @@ static int setup_frame(int sig, struct k
frame = get_sigframe(ka, regs, sizeof(*frame));
+ if ((ka->sa.sa_flags & SA_ONSTACK) && + !sas_ss_flags((unsigned long)frame)) + goto give_sigsegv; + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv;
@@ -425,6 +429,10 @@ static int setup_rt_frame(int sig, struc
frame = get_sigframe(ka, regs, sizeof(*frame));
+ if ((ka->sa.sa_flags & SA_ONSTACK) && + !sas_ss_flags((unsigned long)frame)) + goto give_sigsegv; + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv;
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