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2021-10-25fortify: strlen: Avoid shadowing previous localsQian Cai
The __compiletime_strlen() macro expansion will shadow p_size and p_len local variables. No callers currently use any of the shadowed names for their "p" variable, so there are no code generation problems. Add "__" prefixes to variable definitions __compiletime_strlen() to avoid new W=2 warnings: ./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); | ^~~~~~ Signed-off-by: Qian Cai <quic_qiancai@quicinc.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20211025210528.261643-1-quic_qiancai@quicinc.com
2021-09-25fortify: Allow strlen() and strnlen() to pass compile-time known lengthsKees Cook
Under CONFIG_FORTIFY_SOURCE, it is possible for the compiler to perform strlen() and strnlen() at compile-time when the string size is known. This is required to support compile-time overflow checking in strlcpy(). Signed-off-by: Kees Cook <keescook@chromium.org>
2021-09-25fortify: Prepare to improve strnlen() and strlen() warningsKees Cook
In order to have strlen() use fortified strnlen() internally, swap their positions in the source. Doing this as part of later changes makes review difficult, so reoroder it here; no code changes. Cc: Francis Laniel <laniel_francis@privacyrequired.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2021-09-25fortify: Fix dropped strcpy() compile-time write overflow checkKees Cook
The implementation for intra-object overflow in str*-family functions accidentally dropped compile-time write overflow checking in strcpy(), leaving it entirely to run-time. Add back the intended check. Fixes: 6a39e62abbaf ("lib: string.h: detect intra-object overflow in fortified string functions") Cc: Daniel Axtens <dja@axtens.net> Cc: Francis Laniel <laniel_francis@privacyrequired.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2021-09-25fortify: Move remaining fortify helpers into fortify-string.hKees Cook
When commit a28a6e860c6c ("string.h: move fortified functions definitions in a dedicated header.") moved the fortify-specific code, some helpers were left behind. Move the remaining fortify-specific helpers into fortify-string.h so they're together where they're used. This requires that any FORTIFY helper function prototypes be conditionally built to avoid "no prototype" warnings. Additionally removes unused helpers. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Daniel Axtens <dja@axtens.net> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Acked-by: Francis Laniel <laniel_francis@privacyrequired.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2021-02-26string.h: move fortified functions definitions in a dedicated header.Francis Laniel
This patch adds fortify-string.h to contain fortified functions definitions. Thus, the code is more separated and compile time is approximately 1% faster for people who do not set CONFIG_FORTIFY_SOURCE. Link: https://lkml.kernel.org/r/20210111092141.22946-1-laniel_francis@privacyrequired.com Link: https://lkml.kernel.org/r/20210111092141.22946-2-laniel_francis@privacyrequired.com Signed-off-by: Francis Laniel <laniel_francis@privacyrequired.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>