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
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>
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>
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: 6a39e62abb ("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>
When commit a28a6e860c ("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>
Qian Cai