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| author |   Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-08-31 13:18:22 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-08-31 14:03:21 +0200 |
| commit | 8ab867cb0806a8e195de161fd8883a0578d1d050 (patch) | |
| tree | 1181aefbc32ee92ad98c96f457581311f3229a3f /arch/s390/mm/mmap.c | |
| parent | s390/mm: fork vs. 5 level page tabel (diff) | |
| download | linux-dev-8ab867cb0806a8e195de161fd8883a0578d1d050.tar.xz linux-dev-8ab867cb0806a8e195de161fd8883a0578d1d050.zip | |
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>
Diffstat (limited to 'arch/s390/mm/mmap.c')
| -rw-r--r-- | arch/s390/mm/mmap.c | 6 |
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; |