[openwrt/openwrt] mbedtls: fix build on GCC 14

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/a41747ac8e824b5cb9ed6874a688a4d5a578e10c

commit a41747ac8e824b5cb9ed6874a688a4d5a578e10c
Author: Rany Hany <rany_hany at riseup.net>
AuthorDate: Mon May 13 20:09:44 2024 +0300

    mbedtls: fix build on GCC 14
    
    Without this patch, GCC 14 incorrectly complains about the following error:
    
    In file included from /home/user/workspace/mbedtls/library/ctr_drbg.c:13:
    In function ‘mbedtls_xor’,
        inlined from ‘ctr_drbg_update_internal’ at /home/user/workspace/mbedtls/library/ctr_drbg.c:372:5:
    /home/user/workspace/mbedtls/library/common.h:235:17: error: array subscript 48 is outside array bounds of ‘unsigned char[48]’ [-Werror=array-bounds=]
      235 |         r[i] = a[i] ^ b[i];
          |                ~^~~
    /home/user/workspace/mbedtls/library/ctr_drbg.c: In function ‘ctr_drbg_update_internal’:
    /home/user/workspace/mbedtls/library/ctr_drbg.c:335:19: note: at offset 48 into object ‘tmp’ of size 48
      335 |     unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN];
          |                   ^~~
    In function ‘mbedtls_xor’,
        inlined from ‘ctr_drbg_update_internal’ at /home/user/workspace/mbedtls/library/ctr_drbg.c:372:5:
    /home/user/workspace/mbedtls/library/common.h:235:24: error: array subscript 48 is outside array bounds of ‘const unsigned char[48]’ [-Werror=array-bounds=]
      235 |         r[i] = a[i] ^ b[i];
          |                       ~^~~
    /home/user/workspace/mbedtls/library/ctr_drbg.c: In function ‘ctr_drbg_update_internal’:
    /home/user/workspace/mbedtls/library/ctr_drbg.c:333:57: note: at offset 48 into object ‘data’ of size [0, 48]
      333 |                                     const unsigned char data[MBEDTLS_CTR_DRBG_SEEDLEN])
          |                                     ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    In function ‘mbedtls_xor’,
        inlined from ‘ctr_drbg_update_internal’ at /home/user/workspace/mbedtls/library/ctr_drbg.c:372:5:
    /home/user/workspace/mbedtls/library/common.h:235:14: error: array subscript 48 is outside array bounds of ‘unsigned char[48]’ [-Werror=array-bounds=]
      235 |         r[i] = a[i] ^ b[i];
          |         ~~~~~^~~~~~~~~~~~~
    /home/user/workspace/mbedtls/library/ctr_drbg.c: In function ‘ctr_drbg_update_internal’:
    /home/user/workspace/mbedtls/library/ctr_drbg.c:335:19: note: at offset 48 into object ‘tmp’ of size 48
      335 |     unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN];
          |                   ^~~
    
    This change adds a basic check to silence the warning until a solution is worked on upstream.
    As this check is already used by another compiler, it shouldn't cause any issues for us.
    
    Signed-off-by: Rany Hany <rany_hany at riseup.net>
---
 package/libs/mbedtls/patches/100-fix-gcc14-build.patch | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/package/libs/mbedtls/patches/100-fix-gcc14-build.patch b/package/libs/mbedtls/patches/100-fix-gcc14-build.patch
new file mode 100644
index 0000000000..656e605814
--- /dev/null
+++ b/package/libs/mbedtls/patches/100-fix-gcc14-build.patch
@@ -0,0 +1,11 @@
+--- a/library/common.h
++++ b/library/common.h
+@@ -199,7 +199,7 @@ static inline void mbedtls_xor(unsigned
+         uint8x16_t x = veorq_u8(v1, v2);
+         vst1q_u8(r + i, x);
+     }
+-#if defined(__IAR_SYSTEMS_ICC__)
++#if defined(__IAR_SYSTEMS_ICC__) || (defined(MBEDTLS_COMPILER_IS_GCC) && MBEDTLS_GCC_VERSION >= 140100)
+     /* This if statement helps some compilers (e.g., IAR) optimise out the byte-by-byte tail case
+      * where n is a constant multiple of 16.
+      * For other compilers (e.g. recent gcc and clang) it makes no difference if n is a compile-time