Medium · published December 27, 2024
In the Linux kernel, the following vulnerability has been resolved:
unicode: Fix utf8_load() error path
utf8_load() requests the symbol "utf8_data_table" and then checks if the
requested UTF-8 version is supported. If it's unsupported, it tries to
put the data table using symbol_put(). If an unsupported version is
requested, symbol_put() fails like this:
kernel BUG at kernel/module/main.c:786!
RIP: 0010:__symbol_put+0x93/0xb0
Call Trace:
<TASK>
? __die_body.cold+0x19/0x27
? die+0x2e/0x50
? do_trap+0xca/0x110
? do_error_trap+0x65/0x80
? __symbol_put+0x93/0xb0
? exc_invalid_op+0x51/0x70
? __symbol_put+0x93/0xb0
? asm_exc_invalid_op+0x1a/0x20
? __pfx_cmp_name+0x10/0x10
? __symbol_put+0x93/0xb0
? __symbol_put+0x62/0xb0
utf8_load+0xf8/0x150
That happens because symbol_put() expects the unique string that
identify the symbol, instead of a pointer to the loaded symbol. Fix that
by using such string.