If do_sendfile is called with a "max" value of 0, it grabs the lesser
s_maxbytes value of the two superblocks to use instead. There's a
problem here however. s_maxbytes is an unsigned long long and it gets
cast to a signed value. If both s_maxbytes values are large enough, max
will end up being negative and the comparisons in this code won't work
correctly.
Change do_sendfile to use unsigned values internally for the offset
checks.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/read_write.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index 6c8c55d..36899ff 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -788,11 +788,11 @@ SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
}
static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
- size_t count, loff_t max)
+ size_t count, unsigned long long max)
{
struct file * in_file, * out_file;
struct inode * in_inode, * out_inode;
- loff_t pos;
+ unsigned long long pos;
ssize_t retval;
int fput_needed_in, fput_needed_out, fl;
@@ -838,7 +838,7 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
if (!max)
max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
- pos = *ppos;
+ pos = (unsigned long long) *ppos;
retval = -EINVAL;
if (unlikely(pos < 0))
goto fput_out;
--
1.6.0.6
--
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