diff options
| -rw-r--r-- | drivers/char/mem.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 48788db4e28..e3f5577cbce 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -708,16 +708,23 @@ static loff_t memory_lseek(struct file * file, loff_t offset, int orig) mutex_lock(&file->f_path.dentry->d_inode->i_mutex); switch (orig) { - case 0: + case SEEK_CUR: + offset += file->f_pos; + if ((unsigned long long)offset < + (unsigned long long)file->f_pos) { + ret = -EOVERFLOW; + break; + } + case SEEK_SET: + /* to avoid userland mistaking f_pos=-9 as -EBADF=-9 */ + if ((unsigned long long)offset >= ~0xFFFULL) { + ret = -EOVERFLOW; + break; + } file->f_pos = offset; ret = file->f_pos; force_successful_syscall_return(); break; - case 1: - file->f_pos += offset; - ret = file->f_pos; - force_successful_syscall_return(); - break; default: ret = -EINVAL; } |