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| author | Ian Abbott <abbotti@mev.co.uk> | 2020-01-14 18:25:31 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-15 13:30:08 +0100 |
| commit | 01e20b664f808a4f3048ca3f930911fd257209bd (patch) | |
| tree | f8ea9b26231d88dd400b7408d3885679fbfb9fa6 | |
| parent | bc80573ea25bb033a58da81b3ce27205b97c088e (diff) | |
| download | linux-01e20b664f808a4f3048ca3f930911fd257209bd.tar.bz2 | |
staging: comedi: ni_routes: fix null dereference in ni_find_route_source()
In `ni_find_route_source()`, `tables->route_values` gets dereferenced.
However it is possible that `tables->route_values` is `NULL`, leading to
a null pointer dereference. `tables->route_values` will be `NULL` if
the call to `ni_assign_device_routes()` during board initialization
returned an error due to missing device family routing information or
missing board-specific routing information. For example, there is
currently no board-specific routing information provided for the
PCIe-6251 board and several other boards, so those are affected by this
bug.
The bug is triggered when `ni_find_route_source()` is called via
`ni_check_trigger_arg()` or `ni_check_trigger_arg_roffs()` when checking
the arguments for setting up asynchronous commands. Fix it by returning
`-EINVAL` if `tables->route_values` is `NULL`.
Even with this fix, setting up asynchronous commands to use external
trigger sources for boards with missing routing information will still
fail gracefully. Since `ni_find_route_source()` only depends on the
device family routing information, it would be better if that was made
available even if the board-specific routing information is missing.
That will be addressed by another patch.
Fixes: 4bb90c87abbe ("staging: comedi: add interface to ni routing table information")
Cc: <stable@vger.kernel.org> # 4.20+
Cc: Spencer E. Olson <olsonse@umich.edu>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20200114182532.132058-2-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/comedi/drivers/ni_routes.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/staging/comedi/drivers/ni_routes.c b/drivers/staging/comedi/drivers/ni_routes.c index 673d732dcb8f..9627bd1d2a78 100644 --- a/drivers/staging/comedi/drivers/ni_routes.c +++ b/drivers/staging/comedi/drivers/ni_routes.c @@ -487,6 +487,9 @@ int ni_find_route_source(const u8 src_sel_reg_value, int dest, { int src; + if (!tables->route_values) + return -EINVAL; + dest = B(dest); /* subtract NI names offset */ /* ensure we are not going to under/over run the route value table */ if (dest < 0 || dest >= NI_NUM_NAMES) |