On Fri, 20 Nov 2015, Chris J Arges wrote: > Currently, patching objects with duplicate symbol names fail because the > creation of the sysfs function directory collides with the previous > attempt. Appending old_addr to the function name is problematic as it > reveals the address of the function being patch to a normal user. Using > the symbol's occurrence in kallsyms to postfix the function name in the > sysfs directory solves the issue of having consistent unique names and > ensuring that the address is not exposed to a normal user. > > In addition, using the symbol position as the user's method to disambiguate > symbols instead of addr allows for disambiguating symbols in modules as > well for both function addresses and for relocs. This also simplifies much > of the code. Special handling for kASLR is no longer needed and can be > removed. The klp_find_verify_func_addr function can be replaced by > klp_find_object_symbol, and klp_verify_vmlinux_symbol and its callback can > be removed completely. > > In cases of duplicate symbols, old_sympos will be used to disambiguate > instead of old_addr. By default old_sympos will be 0, and patching will > only succeed if the symbol is unique. Specifying a positive value will > ensure that occurrence of the symbol in kallsyms for the patched object > will be used for patching if it is valid. > > In addition, make old_addr an internal structure field not to be specified > by the user. Finally, remove klp_find_verify_func_addr as it can be > replaced by klp_find_object_symbol directly. > > Support for symbol position disambiguation for relocations is added in the > next patch in this series. > > Signed-off-by: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx> Reviewed-by: Miroslav Benes <mbenes@xxxxxxx> Miroslav -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
