diff options
| author | Wu Fengguang <fengguang.wu@intel.com> | 2010-03-11 02:21:51 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-13 02:52:35 +0300 |
| commit | dcefafb6ac90ece8d68a6c203105f3d313e52da4 (patch) | |
| tree | c0aad5b135dc95f2aaa8d3c089a1ac44144ef424 | |
| parent | 2cb9a75d13676d75bcc6fbc6f885403795581913 (diff) | |
| download | linux-dcefafb6ac90ece8d68a6c203105f3d313e52da4.tar.xz | |
/dev/mem: dont allow seek to last page
So as to return a uniform error -EOVERFLOW instead of a random one:
# kmem-seek 0xfffffffffffffff0
seek /dev/kmem: Device or resource busy
# kmem-seek 0xfffffffffffffff1
seek /dev/kmem: Block device required
Suggested by OGAWA Hirofumi.
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -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 48788db4e280..e3f5577cbce3 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; } |