Hi Al, Any comments? On 12/08/2010 06:25 PM, Harsh Prateek Bora wrote:
The existing code causes the if condition to pass when it should fail on a *64-bit kernel* because of implicit data type conversions. It can be observed by passing pos = -1 and count = some positive number. This results in function returning EOVERFLOW instead of EINVAL. With this patch, the function returns EINVAL when pos is -1 and count is a positive number. This can be tested by calling sendfile with offset = -1 and count = some positive number on a 64-bit kernel. Signed-off-by: Harsh Prateek Bora<harsh@xxxxxxxxxxxxxxxxxx> --- fs/read_write.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 431a0ed..a8eabd4 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -38,7 +38,7 @@ __negative_fpos_check(struct file *file, loff_t pos, size_t count) * pos or pos+count is negative here, check overflow. * too big "count" will be caught in rw_verify_area(). */ - if ((pos< 0)&& (pos + count< pos)) + if ((pos< 0)&& ( (loff_t) (pos + count)< pos)) return -EOVERFLOW; if (file->f_mode& FMODE_UNSIGNED_OFFSET) return 0;
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