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; -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
