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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-10-20 00:10:27 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-10-20 00:10:27 -0300
commitd0b2f91bede3bd5e3d24dd6803e56eee959c1797 (patch)
tree7fee4ab0509879c373c4f2cbd5b8a5be5b4041ee /arch/x86/kernel/signal_compat.c
parente914f8eb445e8f74b00303c19c2ffceaedd16a05 (diff)
Linux-libre 4.8.2-gnupck-4.8.2-gnu
Diffstat (limited to 'arch/x86/kernel/signal_compat.c')
-rw-r--r--arch/x86/kernel/signal_compat.c108
1 files changed, 108 insertions, 0 deletions
diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
index dc3c0b1c8..b44564bf8 100644
--- a/arch/x86/kernel/signal_compat.c
+++ b/arch/x86/kernel/signal_compat.c
@@ -1,11 +1,104 @@
#include <linux/compat.h>
#include <linux/uaccess.h>
+/*
+ * The compat_siginfo_t structure and handing code is very easy
+ * to break in several ways. It must always be updated when new
+ * updates are made to the main siginfo_t, and
+ * copy_siginfo_to_user32() must be updated when the
+ * (arch-independent) copy_siginfo_to_user() is updated.
+ *
+ * It is also easy to put a new member in the compat_siginfo_t
+ * which has implicit alignment which can move internal structure
+ * alignment around breaking the ABI. This can happen if you,
+ * for instance, put a plain 64-bit value in there.
+ */
+static inline void signal_compat_build_tests(void)
+{
+ int _sifields_offset = offsetof(compat_siginfo_t, _sifields);
+
+ /*
+ * If adding a new si_code, there is probably new data in
+ * the siginfo. Make sure folks bumping the si_code
+ * limits also have to look at this code. Make sure any
+ * new fields are handled in copy_siginfo_to_user32()!
+ */
+ BUILD_BUG_ON(NSIGILL != 8);
+ BUILD_BUG_ON(NSIGFPE != 8);
+ BUILD_BUG_ON(NSIGSEGV != 4);
+ BUILD_BUG_ON(NSIGBUS != 5);
+ BUILD_BUG_ON(NSIGTRAP != 4);
+ BUILD_BUG_ON(NSIGCHLD != 6);
+ BUILD_BUG_ON(NSIGSYS != 1);
+
+ /* This is part of the ABI and can never change in size: */
+ BUILD_BUG_ON(sizeof(compat_siginfo_t) != 128);
+ /*
+ * The offsets of all the (unioned) si_fields are fixed
+ * in the ABI, of course. Make sure none of them ever
+ * move and are always at the beginning:
+ */
+ BUILD_BUG_ON(offsetof(compat_siginfo_t, _sifields) != 3 * sizeof(int));
+#define CHECK_CSI_OFFSET(name) BUILD_BUG_ON(_sifields_offset != offsetof(compat_siginfo_t, _sifields.name))
+
+ /*
+ * Ensure that the size of each si_field never changes.
+ * If it does, it is a sign that the
+ * copy_siginfo_to_user32() code below needs to updated
+ * along with the size in the CHECK_SI_SIZE().
+ *
+ * We repeat this check for both the generic and compat
+ * siginfos.
+ *
+ * Note: it is OK for these to grow as long as the whole
+ * structure stays within the padding size (checked
+ * above).
+ */
+#define CHECK_CSI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((compat_siginfo_t *)0)->_sifields.name))
+#define CHECK_SI_SIZE(name, size) BUILD_BUG_ON(size != sizeof(((siginfo_t *)0)->_sifields.name))
+
+ CHECK_CSI_OFFSET(_kill);
+ CHECK_CSI_SIZE (_kill, 2*sizeof(int));
+ CHECK_SI_SIZE (_kill, 2*sizeof(int));
+
+ CHECK_CSI_OFFSET(_timer);
+ CHECK_CSI_SIZE (_timer, 5*sizeof(int));
+ CHECK_SI_SIZE (_timer, 6*sizeof(int));
+
+ CHECK_CSI_OFFSET(_rt);
+ CHECK_CSI_SIZE (_rt, 3*sizeof(int));
+ CHECK_SI_SIZE (_rt, 4*sizeof(int));
+
+ CHECK_CSI_OFFSET(_sigchld);
+ CHECK_CSI_SIZE (_sigchld, 5*sizeof(int));
+ CHECK_SI_SIZE (_sigchld, 8*sizeof(int));
+
+ CHECK_CSI_OFFSET(_sigchld_x32);
+ CHECK_CSI_SIZE (_sigchld_x32, 7*sizeof(int));
+ /* no _sigchld_x32 in the generic siginfo_t */
+
+ CHECK_CSI_OFFSET(_sigfault);
+ CHECK_CSI_SIZE (_sigfault, 4*sizeof(int));
+ CHECK_SI_SIZE (_sigfault, 8*sizeof(int));
+
+ CHECK_CSI_OFFSET(_sigpoll);
+ CHECK_CSI_SIZE (_sigpoll, 2*sizeof(int));
+ CHECK_SI_SIZE (_sigpoll, 4*sizeof(int));
+
+ CHECK_CSI_OFFSET(_sigsys);
+ CHECK_CSI_SIZE (_sigsys, 3*sizeof(int));
+ CHECK_SI_SIZE (_sigsys, 4*sizeof(int));
+
+ /* any new si_fields should be added here */
+}
+
int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
{
int err = 0;
bool ia32 = test_thread_flag(TIF_IA32);
+ signal_compat_build_tests();
+
if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
return -EFAULT;
@@ -32,6 +125,21 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
&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) {
+ compat_uptr_t lower = (unsigned long)&to->si_lower;
+ compat_uptr_t upper = (unsigned long)&to->si_upper;
+ put_user_ex(lower, &to->si_lower);
+ put_user_ex(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);