[PATCH] Fix compat shmget overflow

This fixes an incorrect sign extension in the compat layer that breaks
32bit shmget that are >2GB.  sys_shmget has a signed size_t size argument,
and the int size argument coming from 32bit user space would get sign
extended to 64bit, which is wrong.

I fixed it on all compat architectures, except PPC64 which was already ok. 

It was originally debugged and fixed by Karl Rister @ IBM for SLES9 on x86-64.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ia64/ia32/sys_ia32.c

@@ -1415,7 +1415,7 @@ sys32_ipc(u32 call, int first, int second, int third, u32 ptr, u32 fifth)
 	      case SHMDT:
 		return sys_shmdt(compat_ptr(ptr));
 	      case SHMGET:
-		return sys_shmget(first, second, third);
+		return sys_shmget(first, (unsigned)second, third);
 	      case SHMCTL:
 		return compat_sys_shmctl(first, second, compat_ptr(ptr));
 

arch/mips/kernel/linux32.c

@@ -1115,7 +1115,7 @@ sys32_ipc (u32 call, int first, int second, int third, u32 ptr, u32 fifth)
 		err = sys_shmdt ((char *)A(ptr));
 		break;
 	case SHMGET:
-		err = sys_shmget (first, second, third);
+		err = sys_shmget (first, (unsigned)second, third);
 		break;
 	case SHMCTL:
 		err = do_sys32_shmctl (first, second, (void *)AA(ptr));

arch/s390/kernel/compat_linux.c

@@ -331,7 +331,7 @@ asmlinkage long sys32_ipc(u32 call, int first, int second, int third, u32 ptr)
 	case SHMDT:
 		return sys_shmdt(compat_ptr(ptr));
 	case SHMGET:
-		return sys_shmget(first, second, third);
+		return sys_shmget(first, (unsigned)second, third);
 	case SHMCTL:
 		return compat_sys_shmctl(first, second, compat_ptr(ptr));
 	}

arch/sparc64/kernel/sys_sparc32.c

@@ -835,7 +835,7 @@ asmlinkage long compat_sys_ipc(u32 call, int first, int second, int third, compa
 			err = sys_shmdt(ptr);
 			goto out;
 		case SHMGET:
-			err = sys_shmget(first, second, third);
+			err = sys_shmget(first, (unsigned)second, third);
 			goto out;
 		case SHMCTL:
 			err = do_sys32_shmctl(first, second, ptr);

arch/x86_64/ia32/ipc32.c

@@ -49,7 +49,7 @@ sys32_ipc(u32 call, int first, int second, int third,
 	      case SHMDT:
 		return sys_shmdt(compat_ptr(ptr));
 	      case SHMGET:
-		return sys_shmget(first, second, third);
+		return sys_shmget(first, (unsigned)second, third);
 	      case SHMCTL:
 		return compat_sys_shmctl(first, second, compat_ptr(ptr));
 	}