Sending this out early so folks can have a look. I haven't let
it run through a full set of tests, so buyer beware, but it would
have a hard time hurting anything other than the already-broken
32-bit compat signal code.
---
From: Dave Hansen <dave.han...@linux.intel.com>
The 32-bit siginfo is a different binary format than the 64-bit
one. So, when running 32-bit binaries on 64-bit kernels, we have
to convert the kernel's 64-bit version to a 32-bit version that
userspace can grok.
We've added a few features to siginfo over the past few years and
neglected to add them to arch/x86/kernel/signal_compat.c:
1. The si_addr_lsb used in SIGBUS's sent for machine checks
2. The upper/lower bounds for MPX SIGSEGV faults
3. The protection key for pkey faults
I caught this with some protection keys unit tests and realized
it affected a few more features.
This was tested only with my protection keys patch that looks
for a proper value in si_pkey. I didn't actually test the machine
check or MPX code.
Signed-off-by: Dave Hansen <dave.han...@linux.intel.com>
Cc: Tony Luck <tony.l...@intel.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: linux-e...@vger.kernel.org
Cc: x...@kernel.org
Cc: Andy Lutomirski <l...@kernel.org>
---
b/arch/x86/include/asm/compat.h | 11 +++++++++++
b/arch/x86/kernel/signal_compat.c | 13 +++++++++++++
2 files changed, 24 insertions(+)
diff -puN arch/x86/include/asm/compat.h~add-signal-compat-for-mpx-pkeys
arch/x86/include/asm/compat.h
--- a/arch/x86/include/asm/compat.h~add-signal-compat-for-mpx-pkeys
2016-05-18 15:29:27.238736544 -0700
+++ b/arch/x86/include/asm/compat.h 2016-05-18 15:29:27.243736772 -0700
@@ -40,6 +40,7 @@ typedef s32 compat_long_t;
typedef s64 __attribute__((aligned(4))) compat_s64;
typedef u32 compat_uint_t;
typedef u32 compat_ulong_t;
+typedef u32 compat_u32;
typedef u64 __attribute__((aligned(4))) compat_u64;
typedef u32 compat_uptr_t;
@@ -181,6 +182,16 @@ typedef struct compat_siginfo {
/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
struct {
unsigned int _addr; /* faulting insn/memory ref. */
+ short int _addr_lsb; /* Valid LSB of the reported
address. */
+ union {
+ /* used when si_code=SEGV_BNDERR */
+ struct {
+ compat_uptr_t _lower;
+ compat_uptr_t _upper;
+ } _addr_bnd;
+ /* used when si_code=SEGV_PKUERR */
+ compat_u32 _pkey;
+ };
} _sigfault;
/* SIGPOLL */
diff -puN arch/x86/kernel/signal_compat.c~add-signal-compat-for-mpx-pkeys
arch/x86/kernel/signal_compat.c
--- a/arch/x86/kernel/signal_compat.c~add-signal-compat-for-mpx-pkeys
2016-05-18 15:29:27.240736635 -0700
+++ b/arch/x86/kernel/signal_compat.c 2016-05-18 16:54:54.366568908 -0700
@@ -32,6 +32,19 @@ int copy_siginfo_to_user32(compat_siginf
&to->_sifields._pad[0]);
switch (from->si_code >> 16) {
case __SI_FAULT >> 16:
+ if (from->si_signo == SIGBUS &&
+ (from->si_code == BUS_MCEERR_AR ||
+ from->si_code == BUS_MCEERR_AO))
+ put_user_ex(from->si_addr_lsb,
&to->si_addr_lsb);
+
+ if (from->si_signo == SIGSEGV) {
+ if (from->si_code == SEGV_BNDERR) {
+ put_user_ex(from->si_lower,
&to->si_lower);
+ put_user_ex(from->si_upper,
&to->si_upper);
+ }
+ if (from->si_code == SEGV_PKUERR)
+ put_user_ex(from->si_pkey,
&to->si_pkey);
+ }
break;
case __SI_SYS >> 16:
put_user_ex(from->si_syscall, &to->si_syscall);
_
