It is possible to indirectly invoke functions with prototypes that do not match those of the respectively used function pointers by using void types or casts. This feature is frequently used as a way of relaxing function invocation, making it possible that different data structures are passed to different functions through the same pointer. Despite the benefits, this can lead to a situation where functions with a given prototype are invoked by pointers with a different prototype. This is undesirable as it may prevent the use of heuristics such as prototype matching-based Control-Flow Integrity, which can be used to prevent ROP-based attacks. One way of fixing this situation is through the use of inline helper functions with prototypes that match the one in the respective invoking pointer. Given the above, the current efforts to improve the Linux security, and the upcoming kernel support to compilers with CFI features, this creates macros to be used to build the needed function definitions, to be used in camellia, cast6, serpent, twofish, and aesni. -Kees (and Joao) v3: - no longer RFC - consolidate macros into glue_helper.h - include aesni which was using casts as well - remove XTS_TWEAK_CAST while we're at it v2: - update cast macros for clarity v1: - initial prototype Joao Moreira (4): crypto: x86/crypto: Use new glue function macros crypto: x86/camellia: Use new glue function macros crypto: x86/twofish: Use new glue function macros crypto: x86/cast6: Use new glue function macros Kees Cook (3): crypto: x86/glue_helper: Add static inline function glue macros crypto: x86/aesni: Use new glue function macros crypto: x86/glue_helper: Remove function prototype cast helpers arch/x86/crypto/aesni-intel_glue.c | 31 ++++----- arch/x86/crypto/camellia_aesni_avx2_glue.c | 73 +++++++++------------- arch/x86/crypto/camellia_aesni_avx_glue.c | 63 +++++++------------ arch/x86/crypto/camellia_glue.c | 21 +++---- arch/x86/crypto/cast6_avx_glue.c | 65 +++++++++---------- arch/x86/crypto/serpent_avx2_glue.c | 65 +++++++++---------- arch/x86/crypto/serpent_avx_glue.c | 58 ++++++----------- arch/x86/crypto/serpent_sse2_glue.c | 27 +++++--- arch/x86/crypto/twofish_avx_glue.c | 71 ++++++++------------- arch/x86/crypto/twofish_glue_3way.c | 28 ++++----- arch/x86/include/asm/crypto/camellia.h | 64 ++++++------------- arch/x86/include/asm/crypto/glue_helper.h | 34 ++++++++-- arch/x86/include/asm/crypto/serpent-avx.h | 28 ++++----- arch/x86/include/asm/crypto/twofish.h | 22 ++++--- include/crypto/xts.h | 2 - 15 files changed, 283 insertions(+), 369 deletions(-) -- 2.17.1
