diff options
| -rw-r--r-- | mm/mmap.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 45ac5b973459..fb2b575dd86c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1312,6 +1312,35 @@ static inline int mlock_future_check(struct mm_struct *mm, return 0; } +static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) +{ + if (S_ISREG(inode->i_mode)) + return inode->i_sb->s_maxbytes; + + if (S_ISBLK(inode->i_mode)) + return MAX_LFS_FILESIZE; + + /* Special "we do even unsigned file positions" case */ + if (file->f_mode & FMODE_UNSIGNED_OFFSET) + return 0; + + /* Yes, random drivers might want more. But I'm tired of buggy drivers */ + return ULONG_MAX; +} + +static inline bool file_mmap_ok(struct file *file, struct inode *inode, + unsigned long pgoff, unsigned long len) +{ + u64 maxsize = file_mmap_size_max(file, inode); + + if (maxsize && len > maxsize) + return false; + maxsize -= len; + if (pgoff > maxsize >> PAGE_SHIFT) + return false; + return true; +} + /* * The caller must hold down_write(¤t->mm->mmap_sem). */ @@ -1384,6 +1413,9 @@ unsigned long do_mmap(struct file *file, unsigned long addr, if (file) { struct inode *inode = file_inode(file); + if (!file_mmap_ok(file, inode, pgoff, len)) + return -EOVERFLOW; + switch (flags & MAP_TYPE) { case MAP_SHARED: if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) |