Messages in this thread | | | Subject | Re: [PATCH] fortify: Avoid shadowing previous locals | From | Qian Cai <> | Date | Mon, 25 Oct 2021 16:15:28 -0400 |
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On 10/25/21 3:34 PM, Kees Cook wrote: > On Mon, Oct 25, 2021 at 02:37:28PM -0400, Qian Cai wrote: >> __compiletime_strlen macro expansion will shadow p_size and p_len local >> variables. Just rename those in __compiletime_strlen. > > They don't escape their local context, though, right? i.e. I don't see a > problem with the existing macro. Did you encounter a specific issue that > this patch fixes?
Yes, this is pretty minor. There are also some extra compiling warnings (W=2) from it.
./include/linux/fortify-string.h: In function 'strnlen':
./include/linux/fortify-string.h:17:9: warning: declaration of 'p_size' shadows a previous local [-Wshadow]
17 | size_t p_size = __builtin_object_size(p, 1); \
| ^~~~~~
./include/linux/fortify-string.h:77:17: note: in expansion of macro '__compiletime_strlen' 77 | size_t p_len = __compiletime_strlen(p);
| ^~~~~~~~~~~~~~~~~~~~
./include/linux/fortify-string.h:76:9: note: shadowed declaration is here
76 | size_t p_size = __builtin_object_size(p, 1);
| ^~~~~~
./include/linux/fortify-string.h:19:10: warning: declaration of 'p_len' shadows a previous local [-Wshadow]
19 | size_t p_len = p_size - 1; \
| ^~~~~
./include/linux/fortify-string.h:77:17: note: in expansion of macro '__compiletime_strlen' 77 | size_t p_len = __compiletime_strlen(p);
| ^~~~~~~~~~~~~~~~~~~~
./include/linux/fortify-string.h:77:9: note: shadowed declaration is here
77 | size_t p_len = __compiletime_strlen(p);
| ^~~~~
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