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authorAndy Lutomirski <luto@amacapital.net>2015-02-13 02:01:14 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-13 05:54:12 +0300
commitf56141e3e2d9aabf7e6b89680ab572c2cdbb2a24 (patch)
tree481e3d99bc1121ce75d505d340153b9d158e60c5 /arch/sparc
parentedc924e023ae2022fc29f1246e115c610c9abf38 (diff)
downloadlinux-f56141e3e2d9aabf7e6b89680ab572c2cdbb2a24.tar.xz
all arches, signal: move restart_block to struct task_struct
If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: David Miller <davem@davemloft.net> Acked-by: Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Mark Salter <msalter@redhat.com> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/include/asm/thread_info_32.h6
-rw-r--r--arch/sparc/include/asm/thread_info_64.h12
-rw-r--r--arch/sparc/kernel/signal32.c4
-rw-r--r--arch/sparc/kernel/signal_32.c2
-rw-r--r--arch/sparc/kernel/signal_64.c2
-rw-r--r--arch/sparc/kernel/traps_64.c2
6 files changed, 7 insertions, 21 deletions
diff --git a/arch/sparc/include/asm/thread_info_32.h b/arch/sparc/include/asm/thread_info_32.h
index 025c98446b1e..fd7bd0a440ca 100644
--- a/arch/sparc/include/asm/thread_info_32.h
+++ b/arch/sparc/include/asm/thread_info_32.h
@@ -47,8 +47,6 @@ struct thread_info {
struct reg_window32 reg_window[NSWINS]; /* align for ldd! */
unsigned long rwbuf_stkptrs[NSWINS];
unsigned long w_saved;
-
- struct restart_block restart_block;
};
/*
@@ -62,9 +60,6 @@ struct thread_info {
.flags = 0, \
.cpu = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
- .restart_block = { \
- .fn = do_no_restart_syscall, \
- }, \
}
#define init_thread_info (init_thread_union.thread_info)
@@ -103,7 +98,6 @@ register struct thread_info *current_thread_info_reg asm("g6");
#define TI_REG_WINDOW 0x30
#define TI_RWIN_SPTRS 0x230
#define TI_W_SAVED 0x250
-/* #define TI_RESTART_BLOCK 0x25n */ /* Nobody cares */
/*
* thread information flag bit numbers
diff --git a/arch/sparc/include/asm/thread_info_64.h b/arch/sparc/include/asm/thread_info_64.h
index 798f0279a4b5..ff455164732a 100644
--- a/arch/sparc/include/asm/thread_info_64.h
+++ b/arch/sparc/include/asm/thread_info_64.h
@@ -58,8 +58,6 @@ struct thread_info {
unsigned long gsr[7];
unsigned long xfsr[7];
- struct restart_block restart_block;
-
struct pt_regs *kern_una_regs;
unsigned int kern_una_insn;
@@ -92,10 +90,9 @@ struct thread_info {
#define TI_RWIN_SPTRS 0x000003c8
#define TI_GSR 0x00000400
#define TI_XFSR 0x00000438
-#define TI_RESTART_BLOCK 0x00000470
-#define TI_KUNA_REGS 0x000004a0
-#define TI_KUNA_INSN 0x000004a8
-#define TI_FPREGS 0x000004c0
+#define TI_KUNA_REGS 0x00000470
+#define TI_KUNA_INSN 0x00000478
+#define TI_FPREGS 0x00000480
/* We embed this in the uppermost byte of thread_info->flags */
#define FAULT_CODE_WRITE 0x01 /* Write access, implies D-TLB */
@@ -124,9 +121,6 @@ struct thread_info {
.current_ds = ASI_P, \
.exec_domain = &default_exec_domain, \
.preempt_count = INIT_PREEMPT_COUNT, \
- .restart_block = { \
- .fn = do_no_restart_syscall, \
- }, \
}
#define init_thread_info (init_thread_union.thread_info)
diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c
index 62deba7be1a9..4eed773a7735 100644
--- a/arch/sparc/kernel/signal32.c
+++ b/arch/sparc/kernel/signal32.c
@@ -150,7 +150,7 @@ void do_sigreturn32(struct pt_regs *regs)
int err, i;
/* Always make any pending restarted system calls return -EINTR */
- current_thread_info()->restart_block.fn = do_no_restart_syscall;
+ current->restart_block.fn = do_no_restart_syscall;
synchronize_user_stack();
@@ -235,7 +235,7 @@ asmlinkage void do_rt_sigreturn32(struct pt_regs *regs)
int err, i;
/* Always make any pending restarted system calls return -EINTR */
- current_thread_info()->restart_block.fn = do_no_restart_syscall;
+ current->restart_block.fn = do_no_restart_syscall;
synchronize_user_stack();
regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
diff --git a/arch/sparc/kernel/signal_32.c b/arch/sparc/kernel/signal_32.c
index 9ee72fc8e0e4..52aa5e4ce5e7 100644
--- a/arch/sparc/kernel/signal_32.c
+++ b/arch/sparc/kernel/signal_32.c
@@ -70,7 +70,7 @@ asmlinkage void do_sigreturn(struct pt_regs *regs)
int err;
/* Always make any pending restarted system calls return -EINTR */
- current_thread_info()->restart_block.fn = do_no_restart_syscall;
+ current->restart_block.fn = do_no_restart_syscall;
synchronize_user_stack();
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c
index 1a6999868031..d88beff47bab 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -254,7 +254,7 @@ void do_rt_sigreturn(struct pt_regs *regs)
int err;
/* Always make any pending restarted system calls return -EINTR */
- current_thread_info()->restart_block.fn = do_no_restart_syscall;
+ current->restart_block.fn = do_no_restart_syscall;
synchronize_user_stack ();
sf = (struct rt_signal_frame __user *)
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 981a769b9558..a27651e866e7 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2730,8 +2730,6 @@ void __init trap_init(void)
TI_NEW_CHILD != offsetof(struct thread_info, new_child) ||
TI_CURRENT_DS != offsetof(struct thread_info,
current_ds) ||
- TI_RESTART_BLOCK != offsetof(struct thread_info,
- restart_block) ||
TI_KUNA_REGS != offsetof(struct thread_info,
kern_una_regs) ||
TI_KUNA_INSN != offsetof(struct thread_info,