In the Linux kernel, the following vulnerability has been resolved:
clk: eswin: Zero-initialize stack-allocated clk_init_data
eswin_clk_register_pll() and eswin_register_clkdiv() declare a struct
clk_init_data on the stack and only initialize some of its fields
(parent_data respectively parent_hws). clk_core_populate_parent_map()
checks parent_names first and parent_data second before falling back
to parent_hws, so leftover stack garbage in the uninitialized fields
hijacks parent resolution and the clk core dereferences a bogus
pointer:
Unable to handle kernel NULL pointer dereference at virtual address 000000000000000c
Oops [#1]
epc : __clk_register+0x31a/0x7f0
[] __clk_register+0x31a/0x7f0
[] devm_clk_hw_register+0x2a/0x94
[] eswin_register_clkdiv+0x80/0xd0
[] eswin_clk_register_clks+0x162/0x1a0
[] eic7700_clk_probe+0x146/0x180
[] platform_probe+0x3c/0x7a
Observed on EIC7700 hardware (with the driver backported to a 6.17
tree); whether the bug triggers depends entirely on what the stack
happens to contain when the registration helpers run.
Zero-initialize both structures.
