From af9d2ff9afaae8040dbf09238b2579f92c93579e Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Tue, 6 Oct 2009 10:34:14 +0200 Subject: [S390] Add EX_TABLE for addressing exception in usercopy functions. This patch adds an EX_TABLE entry to mvc{p|s|os} usercopy functions that may be called with KERNEL_DS. In combination with collaborative memory management, kernel pages marked as unused may trigger an adressing exception in the usercopy functions. This fixes an unhandled addressing exception bug where strncpy_from_user() is used with len > strnlen and KERNEL_DS, crossing a page boundary to an unused page. Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky diff --git a/arch/s390/lib/uaccess_mvcos.c b/arch/s390/lib/uaccess_mvcos.c index 3f15aaf..58da3f4 100644 --- a/arch/s390/lib/uaccess_mvcos.c +++ b/arch/s390/lib/uaccess_mvcos.c @@ -36,7 +36,7 @@ static size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x) tmp1 = -4096UL; asm volatile( "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n" - " jz 7f\n" + "9: jz 7f\n" "1:"ALR" %0,%3\n" " "SLR" %1,%3\n" " "SLR" %2,%3\n" @@ -47,7 +47,7 @@ static size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x) " "CLR" %0,%4\n" /* copy crosses next page boundary? */ " jnh 4f\n" "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n" - " "SLR" %0,%4\n" + "10:"SLR" %0,%4\n" " "ALR" %2,%4\n" "4:"LHI" %4,-1\n" " "ALR" %4,%0\n" /* copy remaining size, subtract 1 */ @@ -61,7 +61,7 @@ static size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x) " j 8f\n" "7:"SLR" %0,%0\n" "8: \n" - EX_TABLE(0b,2b) EX_TABLE(3b,4b) + EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b) : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) : "d" (reg0) : "cc", "memory"); return size; @@ -82,7 +82,7 @@ static size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x) tmp1 = -4096UL; asm volatile( "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n" - " jz 4f\n" + "6: jz 4f\n" "1:"ALR" %0,%3\n" " "SLR" %1,%3\n" " "SLR" %2,%3\n" @@ -93,11 +93,11 @@ static size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x) " "CLR" %0,%4\n" /* copy crosses next page boundary? */ " jnh 5f\n" "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n" - " "SLR" %0,%4\n" + "7:"SLR" %0,%4\n" " j 5f\n" "4:"SLR" %0,%0\n" "5: \n" - EX_TABLE(0b,2b) EX_TABLE(3b,5b) + EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b) : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) : "d" (reg0) : "cc", "memory"); return size; diff --git a/arch/s390/lib/uaccess_std.c b/arch/s390/lib/uaccess_std.c index d2ffbad..07deaee 100644 --- a/arch/s390/lib/uaccess_std.c +++ b/arch/s390/lib/uaccess_std.c @@ -36,12 +36,12 @@ size_t copy_from_user_std(size_t size, const void __user *ptr, void *x) tmp1 = -256UL; asm volatile( "0: mvcp 0(%0,%2),0(%1),%3\n" - " jz 8f\n" + "10:jz 8f\n" "1:"ALR" %0,%3\n" " la %1,256(%1)\n" " la %2,256(%2)\n" "2: mvcp 0(%0,%2),0(%1),%3\n" - " jnz 1b\n" + "11:jnz 1b\n" " j 8f\n" "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ " "LHI" %3,-4096\n" @@ -50,7 +50,7 @@ size_t copy_from_user_std(size_t size, const void __user *ptr, void *x) " "CLR" %0,%4\n" /* copy crosses next page boundary? */ " jnh 5f\n" "4: mvcp 0(%4,%2),0(%1),%3\n" - " "SLR" %0,%4\n" + "12:"SLR" %0,%4\n" " "ALR" %2,%4\n" "5:"LHI" %4,-1\n" " "ALR" %4,%0\n" /* copy remaining size, subtract 1 */ @@ -65,6 +65,7 @@ size_t copy_from_user_std(size_t size, const void __user *ptr, void *x) "8:"SLR" %0,%0\n" "9: \n" EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b) + EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b) : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) : : "cc", "memory"); return size; @@ -85,12 +86,12 @@ size_t copy_to_user_std(size_t size, void __user *ptr, const void *x) tmp1 = -256UL; asm volatile( "0: mvcs 0(%0,%1),0(%2),%3\n" - " jz 5f\n" + "7: jz 5f\n" "1:"ALR" %0,%3\n" " la %1,256(%1)\n" " la %2,256(%2)\n" "2: mvcs 0(%0,%1),0(%2),%3\n" - " jnz 1b\n" + "8: jnz 1b\n" " j 5f\n" "3: la %4,255(%1)\n" /* %4 = ptr + 255 */ " "LHI" %3,-4096\n" @@ -99,11 +100,12 @@ size_t copy_to_user_std(size_t size, void __user *ptr, const void *x) " "CLR" %0,%4\n" /* copy crosses next page boundary? */ " jnh 6f\n" "4: mvcs 0(%4,%1),0(%2),%3\n" - " "SLR" %0,%4\n" + "9:"SLR" %0,%4\n" " j 6f\n" "5:"SLR" %0,%0\n" "6: \n" EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b) + EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b) : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2) : : "cc", "memory"); return size; -- cgit v0.10.2