fix: handle 64-bit byte counts in MD5Update for inputs >= 4 GiB#28
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fix: handle 64-bit byte counts in MD5Update for inputs >= 4 GiB#28
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The 32-bit byte counter (bytes_low/bytes_high) in MD5Update was not
correctly updated when STRLEN (len) exceeded 2^32. The old code:
ctx->bytes_low += len;
if (ctx->bytes_low < len)
ctx->bytes_high++;
On 64-bit systems, when len > 2^32, the implicit truncation of len to
U32 caused the carry detection to fail, producing incorrect digests
for inputs of 8 GiB or more.
The fix explicitly casts len to U32 for the low-word addition, detects
carry by comparing against the previous value of bytes_low, and adds
the high 32 bits of len to bytes_high when STRLEN is wider than 32 bits.
Fixes #6
(migrated from rt.cpan.org #123185)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Docker Hub has removed perl:5.8 through perl:5.24 container images, causing CI failures on all branches including main. Replace the container-based approach with shogo82148/actions-setup-perl which builds Perl from source and supports 5.8+. Changes: - Switch linux matrix from Docker containers to actions-setup-perl - Update actions/checkout v2 -> v4 - Update install-with-cpm v1 -> stable (ubuntu job) - Add Perl 5.34, 5.36, 5.38, 5.40 to test matrix - Drop Perl 5.8 (22 years old, minimal practical value) - Add Windows CI job (Strawberry Perl via actions-setup-perl) - Add macOS CI job (system perl, no container) - Limit AUTHOR_TESTING/RELEASE_TESTING to ubuntu job only Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
Fix incorrect MD5 digests for inputs >= 4 GiB on 64-bit systems. The 32-bit byte counter in
MD5Updatefailed to properly detect carry whenSTRLEN(which is 64-bit on 64-bit systems) exceeded 2^32, causing the message length encoded in the MD5 padding to be wrong.Fixes #6
Changes
MD5Update()inMD5.xsto correctly handle the 64-bit to 32-bit truncation oflenwhen updatingbytes_low/bytes_highcountert/large.tregression test that verifies byte counter correctness across the 4 GiB boundary (without requiring multi-GiB memory allocation)MD5.xsint/files.tTest plan
t/large.ttest verifies byte counter tracks correctly across the 4 GiB boundary usingcontext()to set the counter near the boundaryprove -b t/— 319 tests)Generated by Kōan /fix
Quality Report
Changes: 3 files changed, 94 insertions(+), 4 deletions(-)
Code scan: clean
Tests: passed (OK)
Branch hygiene: clean
Generated by Kōan post-mission quality pipeline