Fix undefined behavior from function pointer type casts flagged by UBSan#619
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bjosv wants to merge 3 commits intoawslabs:mainfrom
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Fix undefined behavior from function pointer type casts flagged by UBSan#619bjosv wants to merge 3 commits intoawslabs:mainfrom
bjosv wants to merge 3 commits intoawslabs:mainfrom
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Replace (aws_hash_callback_eq_fn *) and (aws_hash_callback_destroy_fn *) casts with properly-typed static wrapper functions. Casting function pointers to a different type and calling through that pointer is undefined behavior in C. UBSan reports these at hash_table.c:68 in s_safe_eq_check() where the equals_fn callback is invoked. Signed-off-by: Björn Svensson <bjorn.a.svensson@est.tech>
Add void (*)(void *) wrapper functions for destroy callbacks that have concrete struct pointer signatures. These are passed to aws_ref_count_init() which expects aws_simple_completion_callback (void (*)(void *)). UBSan reports these at ref_count.c:29 when the destroy callback is invoked through the mismatched function pointer type. Signed-off-by: Björn Svensson <bjorn.a.svensson@est.tech>
…stroy Add void (*)(void *) wrapper functions for destroy callbacks registered via aws_ref_count_init() that have concrete struct pointer signatures. Signed-off-by: Björn Svensson <bjorn.a.svensson@est.tech>
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Replace function pointer casts with properly-typed static wrapper functions throughout the codebase.
Casting function pointers to a different type and calling through that pointer is undefined behavior in C (C11
§6.5.2.2¶6), even when the underlying ABI happens to work.
Three categories of casts are fixed:
Each cast is replaced with a small static void wrapper function that forwards to the original.
How to reproduce:
Build as described in https://github.com/awslabs/aws-c-s3?tab=readme-ov-file#building but with UBSan enabled:
-DCMAKE_C_FLAGS="-fsanitize=undefined -fno-sanitize-recover=undefined"-DCMAKE_EXE_LINKER_FLAGS="-fsanitize=undefined"When running tests UBSan will report errors like:
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.