net: dns: Fix potential buffer overflow when unpacking labels
As the loop unpacking the DNS name from records checks the current
label length on each iteration, it's also needed to update the remaining
buffer length on each iteration, otherwise the buffer length checks
doesn't work as expected.
Additionally, the remaining buffer checks while technically worked, they
were conceptually wrong and unintuitive. The buf->data pointer doesn't
move, so comparing against this pointer when adding new labels doesn't
make sense. It's more intuitive to simply compare the label size vs
the remaining buffer space.
Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
(cherry picked from commit 7bd45cd39b49c0613ef831e255d0f09bc75bbfe7)
1 file changed
