From 20f22ab42e9c832bde6e9a7ed04cdc73ec737e5b Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Mon, 4 Mar 2013 14:32:59 -0800 Subject: signals: fix new kernel-doc warnings Fix new kernel-doc warnings in kernel/signal.c: Warning(kernel/signal.c:2689): No description found for parameter 'uset' Warning(kernel/signal.c:2689): Excess function parameter 'set' description in 'sys_rt_sigpending' Signed-off-by: Randy Dunlap Cc: Alexander Viro Signed-off-by: Linus Torvalds --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 2ec870a4c3c4..d63c79e7e415 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2682,7 +2682,7 @@ static int do_sigpending(void *set, unsigned long sigsetsize) /** * sys_rt_sigpending - examine a pending signal that has been raised * while blocked - * @set: stores pending signals + * @uset: stores pending signals * @sigsetsize: size of sigset_t type or larger */ SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize) -- cgit v1.2.3 From 2ca39528c01a933f6689cd6505ce65bd6d68a530 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 13 Mar 2013 14:59:33 -0700 Subject: signal: always clear sa_restorer on execve When the new signal handlers are set up, the location of sa_restorer is not cleared, leaking a parent process's address space location to children. This allows for a potential bypass of the parent's ASLR by examining the sa_restorer value returned when calling sigaction(). Based on what should be considered "secret" about addresses, it only matters across the exec not the fork (since the VMAs haven't changed until the exec). But since exec sets SIG_DFL and keeps sa_restorer, this is where it should be fixed. Given the few uses of sa_restorer, a "set" function was not written since this would be the only use. Instead, we use __ARCH_HAS_SA_RESTORER, as already done in other places. Example of the leak before applying this patch: $ cat /proc/$$/maps ... 7fb9f3083000-7fb9f3238000 r-xp 00000000 fd:01 404469 .../libc-2.15.so ... $ ./leak ... 7f278bc74000-7f278be29000 r-xp 00000000 fd:01 404469 .../libc-2.15.so ... 1 0 (nil) 0x7fb9f30b94a0 2 4000000 (nil) 0x7f278bcaa4a0 3 4000000 (nil) 0x7f278bcaa4a0 4 0 (nil) 0x7fb9f30b94a0 ... [akpm@linux-foundation.org: use SA_RESTORER for backportability] Signed-off-by: Kees Cook Reported-by: Emese Revfy Cc: Emese Revfy Cc: PaX Team Cc: Al Viro Cc: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Serge Hallyn Cc: Julien Tinnes Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index d63c79e7e415..43b0d4a1b7ba 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -485,6 +485,9 @@ flush_signal_handlers(struct task_struct *t, int force_default) if (force_default || ka->sa.sa_handler != SIG_IGN) ka->sa.sa_handler = SIG_DFL; ka->sa.sa_flags = 0; +#ifdef SA_RESTORER + ka->sa.sa_restorer = NULL; +#endif sigemptyset(&ka->sa.sa_mask); ka++; } -- cgit v1.2.3 From 522cff142d7d2f9230839c9e1f21a4d8bcc22a4a Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Wed, 13 Mar 2013 14:59:34 -0700 Subject: kernel/signal.c: use __ARCH_HAS_SA_RESTORER instead of SA_RESTORER __ARCH_HAS_SA_RESTORER is the preferred conditional for use in 3.9 and later kernels, per Kees. Cc: Emese Revfy Cc: Emese Revfy Cc: PaX Team Cc: Al Viro Cc: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Serge Hallyn Cc: Julien Tinnes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 43b0d4a1b7ba..dd72567767d9 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -485,7 +485,7 @@ flush_signal_handlers(struct task_struct *t, int force_default) if (force_default || ka->sa.sa_handler != SIG_IGN) ka->sa.sa_handler = SIG_DFL; ka->sa.sa_flags = 0; -#ifdef SA_RESTORER +#ifdef __ARCH_HAS_SA_RESTORER ka->sa.sa_restorer = NULL; #endif sigemptyset(&ka->sa.sa_mask); -- cgit v1.2.3