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siginfo structure in 64-bit kernel

To: Ralf Baechle <ralf@oss.sgi.com>, "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>, linux-mips@oss.sgi.com
Subject: siginfo structure in 64-bit kernel
From: Carsten Langgaard <carstenl@mips.com>
Date: Wed, 07 Aug 2002 11:54:08 +0200
Sender: owner-linux-mips@oss.sgi.com
The siginfo structure is containing longs, which isn't consistent
between o32 and n64.
So we need a routine to convert siginfo from 64-bit to 32-bit, when we
are running a 64-bit kernel on o32 userland.
Please take a look at the patch below.

/Carsten



--
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Index: arch/mips64/kernel/signal32.c
===================================================================
RCS file: /cvs/linux/arch/mips64/kernel/signal32.c,v
retrieving revision 1.20.2.7
diff -u -r1.20.2.7 signal32.c
--- arch/mips64/kernel/signal32.c       2002/08/05 23:53:36     1.20.2.7
+++ arch/mips64/kernel/signal32.c       2002/08/07 08:52:00
@@ -360,13 +360,55 @@
        sigset_t sf_mask;
 };
 
-struct rt_sigframe {
+struct rt_sigframe32 {
        u32 rs_ass[4];                  /* argument save space for o32 */
        u32 rs_code[2];                 /* signal trampoline */
-       struct siginfo rs_info;
+       struct siginfo32 rs_info;
        struct ucontext rs_uc;
 };
 
+static int copy_siginfo_to_user32(siginfo_t32 *to, siginfo_t *from)
+{
+       int err;
+
+       if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t32)))
+               return -EFAULT;
+
+       /* If you change siginfo_t structure, please be sure
+          this code is fixed accordingly.
+          It should never copy any pad contained in the structure
+          to avoid security leaks, but must copy the generic
+          3 ints plus the relevant union member.
+          This routine must convert siginfo from 64bit to 32bit as well
+          at the same time.  */
+       err = __put_user(from->si_signo, &to->si_signo);
+       err |= __put_user(from->si_errno, &to->si_errno);
+       err |= __put_user((short)from->si_code, &to->si_code);
+       if (from->si_code < 0)
+               err |= __copy_to_user(&to->_sifields._pad, 
&from->_sifields._pad, SI_PAD_SIZE);
+       else {
+               switch (from->si_code >> 16) {
+               case __SI_CHLD >> 16:
+                       err |= __put_user(from->si_utime, &to->si_utime);
+                       err |= __put_user(from->si_stime, &to->si_stime);
+                       err |= __put_user(from->si_status, &to->si_status);
+               default:
+                       err |= __put_user(from->si_pid, &to->si_pid);
+                       err |= __put_user(from->si_uid, &to->si_uid);
+                       break;
+               case __SI_FAULT >> 16:
+                       err |= __put_user((long)from->si_addr, &to->si_addr);
+                       break;
+               case __SI_POLL >> 16:
+                       err |= __put_user(from->si_band, &to->si_band);
+                       err |= __put_user(from->si_fd, &to->si_fd);
+                       break;
+               /* case __SI_RT: This is not generated by the kernel as of now. 
 */
+               }
+       }
+       return err;
+}
+
 asmlinkage void sys32_sigreturn(abi64_no_regargs, struct pt_regs regs)
 {
        struct sigframe *frame;
@@ -405,11 +447,11 @@
 
 asmlinkage void sys32_rt_sigreturn(abi64_no_regargs, struct pt_regs regs)
 {
-       struct rt_sigframe *frame;
+       struct rt_sigframe32 *frame;
        sigset_t set;
        stack_t st;
 
-       frame = (struct rt_sigframe *) regs.regs[29];
+       frame = (struct rt_sigframe32 *) regs.regs[29];
        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
                goto badframe;
        if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
@@ -588,7 +630,7 @@
                                  struct pt_regs *regs, int signr,
                                  sigset_t *set, siginfo_t *info)
 {
-       struct rt_sigframe *frame;
+       struct rt_sigframe32 *frame;
        int err = 0;
 
        frame = get_sigframe(ka, regs, sizeof(*frame));
@@ -613,8 +655,8 @@
                flush_cache_sigtramp((unsigned long) frame->rs_code);
        }
 
-       /* Create siginfo.  */
-       err |= __copy_to_user(&frame->rs_info, info, sizeof(*info));
+       /* Convert (siginfo_t -> siginfo_t32) and copy to user. */
+       err |= copy_siginfo_to_user32(&frame->rs_info,info);
 
        /* Create the ucontext.  */
        err |= __put_user(0, &frame->rs_uc.uc_flags);
@@ -639,7 +681,7 @@
         *   a2 = pointer to ucontext
         *
         * $25 and c0_epc point to the signal handler, $29 points to
-        * the struct rt_sigframe.
+        * the struct rt_sigframe32.
         */
        regs->regs[ 4] = signr;
        regs->regs[ 5] = (unsigned long) &frame->rs_info;
Index: include/asm-mips64/siginfo.h
===================================================================
RCS file: /cvs/linux/include/asm-mips64/siginfo.h,v
retrieving revision 1.6.2.2
diff -u -r1.6.2.2 siginfo.h
--- include/asm-mips64/siginfo.h        2002/08/05 23:53:39     1.6.2.2
+++ include/asm-mips64/siginfo.h        2002/08/07 08:52:16
@@ -18,11 +18,21 @@
        void *sival_ptr;
 } sigval_t;
 
+#ifdef __KERNEL__
+
+typedef union sigval32 {
+       int sival_int;
+       u32 sival_ptr;
+} sigval_t32;
+
+#endif /* __KERNEL__ */
+
 /* This structure matches IRIX 32/n32 ABIs for binary compatibility but
    has Linux extensions.  */
 
 #define SI_MAX_SIZE    128
-#define SI_PAD_SIZE    ((SI_MAX_SIZE/sizeof(int)) - 3)
+#define SI_PAD_SIZE    ((SI_MAX_SIZE/sizeof(int)) - 4)
+#define SI_PAD_SIZE32  ((SI_MAX_SIZE/sizeof(int)) - 3)
 
 typedef struct siginfo {
        int si_signo;
@@ -81,6 +91,67 @@
 
        } _sifields;
 } siginfo_t;
+
+#ifdef __KERNEL__
+
+typedef struct siginfo32 {
+       int si_signo;
+       int si_errno;
+       int si_code;
+       union {
+               int _pad[SI_PAD_SIZE32];
+
+               /* kill() */
+               struct {
+                       __kernel_pid_t32 _pid;  /* sender's pid */
+                       __kernel_uid_t32 _uid;  /* sender's uid */
+               } _kill;
+
+               /* SIGCHLD */
+               struct {
+                       __kernel_pid_t32 _pid;  /* which child */
+                       __kernel_uid_t32 _uid;  /* sender's uid */
+                       __kernel_clock_t32 _utime;
+                       int _status;            /* exit code */
+                       __kernel_clock_t32 _stime;
+               } _sigchld;
+
+               /* IRIX SIGCHLD */
+               struct {
+                       __kernel_pid_t32 _pid;  /* which child */
+                       __kernel_clock_t32 _utime;
+                       int _status;            /* exit code */
+                       __kernel_clock_t32 _stime;
+               } _irix_sigchld;
+
+               /* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
+               struct {
+                       u32 _addr; /* faulting insn/memory ref. */
+               } _sigfault;
+
+               /* SIGPOLL, SIGXFSZ (To do ...)  */
+               struct {
+                       int _band;      /* POLL_IN, POLL_OUT, POLL_MSG */
+                       int _fd;
+               } _sigpoll;
+
+               /* POSIX.1b timers */
+               struct {
+                       unsigned int _timer1;
+                       unsigned int _timer2;
+               } _timer;
+
+               /* POSIX.1b signals */
+               struct {
+                       __kernel_pid_t32 _pid;  /* sender's pid */
+                       __kernel_uid_t32 _uid;  /* sender's uid */
+                       sigval_t32 _sigval;
+               } _rt;
+
+       } _sifields;
+} siginfo_t32;
+
+#endif /* __KERNEL__ */
 
 /*
  * How these fields are to be accessed.
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