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[backport 1.1] platform: fix -Wcast-align warnings in memory_buffer_alloc.c #757

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Merged
valeriosetti merged 1 commit into from
Apr 22, 2026
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[backport 1.1] platform: fix -Wcast-align warnings in memory_buffer_alloc.c #757

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12 changes: 9 additions & 3 deletions platform/memory_buffer_alloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -294,7 +294,9 @@ static void *buffer_alloc_calloc(size_t n, size_t size)
}

p = ((unsigned char *) cur) + sizeof(memory_header) + len;
new = (memory_header *) p;
/* Double casting is required to prevent compilation warning on Clang-based
* compilers when "-Wcast-align" is used. */
new = (memory_header *) (void *) p;
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@bjwtaylor bjwtaylor Apr 15, 2026

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Will this suppress valid warnings, such as when MBEDTLS_MEMORY_ALIGN_MULTIPLE is kept at 4 however the memory is 8 bit aligned and do we need a more robust solution? Or is it sufficient to just suppress the warning?

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@bjwtaylor bjwtaylor Apr 15, 2026

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Apologies, meant to add this as a comment. So I've re-requested the review.


new->size = cur->size - len - sizeof(memory_header);
new->alloc = 0;
Expand Down Expand Up @@ -375,7 +377,9 @@ static void buffer_alloc_free(void *ptr)
}

p -= sizeof(memory_header);
hdr = (memory_header *) p;
/* Double casting is required to prevent compilation warning on Clang-based
* compilers when "-Wcast-align" is used. */
hdr = (memory_header *) (void *) p;

if (verify_header(hdr) != 0) {
mbedtls_exit(1);
Expand Down Expand Up @@ -586,7 +590,9 @@ void mbedtls_memory_buffer_alloc_init(unsigned char *buf, size_t len)
heap.buf = buf;
heap.len = len;

heap.first = (memory_header *) buf;
/* Double casting is required to prevent compilation warning on Clang-based
* compilers when "-Wcast-align" is used. */
heap.first = (memory_header *) (void *) buf;
heap.first->size = len - sizeof(memory_header);
heap.first->magic1 = MAGIC1;
heap.first->magic2 = MAGIC2;
Expand Down