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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2017-08-31 13:18:22 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-08-31 14:03:21 +0200
commit8ab867cb0806a8e195de161fd8883a0578d1d050 (patch)
tree1181aefbc32ee92ad98c96f457581311f3229a3f
parent0b89ede629637c03b9a728fb08bfe6ed51de9be7 (diff)
s390/mm: fix BUG_ON in crst_table_upgrade
A 31-bit compat process can force a BUG_ON in crst_table_upgrade with specific, invalid mmap calls, e.g. mmap((void*) 0x7fff8000, 0x10000, 3, 32, -1, 0) The arch_get_unmapped_area[_topdown] functions miss an if condition in the decision to do a page table upgrade. Fixes: 9b11c7912d00 ("s390/mm: simplify arch_get_unmapped_area[_topdown]") Cc: <stable@vger.kernel.org> # v4.12+ Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/mm/mmap.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 2e10d2b8ad35..5bea139517a2 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -119,7 +119,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
return addr;
check_asce_limit:
- if (addr + len > current->mm->context.asce_limit) {
+ if (addr + len > current->mm->context.asce_limit &&
+ addr + len <= TASK_SIZE) {
rc = crst_table_upgrade(mm, addr + len);
if (rc)
return (unsigned long) rc;
@@ -183,7 +184,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
}
check_asce_limit:
- if (addr + len > current->mm->context.asce_limit) {
+ if (addr + len > current->mm->context.asce_limit &&
+ addr + len <= TASK_SIZE) {
rc = crst_table_upgrade(mm, addr + len);
if (rc)
return (unsigned long) rc;