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Fix integer overflow in wolfSSL_writev #9296

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embhorn wants to merge 2 commits into from
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Fix integer overflow in wolfSSL_writev #9296

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b55b4ca
Fix integer overflow in wolfSSL_writev
embhorn Oct 13, 2025
c243f41
Fix integer overflow in wolfSSL_writev
embhorn Oct 13, 2025
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6 changes: 4 additions & 2 deletions src/ssl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11578,8 +11578,10 @@ int wolfSSL_set_compression(WOLFSSL* ssl)

WOLFSSL_ENTER("wolfSSL_writev");

for (i = 0; i < iovcnt; i++)
sending += iov[i].iov_len;
for (i = 0; i < iovcnt; i++) {
if (!WC_SAFE_SUM_WORD32(sending, (word32)iov[i].iov_len, sending))
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@dgarske dgarske Oct 14, 2025

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Looks good, but technically over 80 chars...

[check-source-text] [4 of 52] [c243f41193]
    configure...   real 0m11.105s  user 0m5.781s  sys 0m3.870s
    [skipping "codespell" subtest in check-source-text -- codespell is missing or too old]
overlong lines added:
src/ssl.c:11582                 if (!WC_SAFE_SUM_WORD32(sending, (word32)iov[i].iov_len, sending))
    check-source-text OK

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@douzzer douzzer Oct 14, 2025

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whoops, there's still a defect here -- you can't blindly truncate .iov_len to word32. you have to check if it fits in a word32 before casting it. we should use size_t for accumulation, and implement WC_SAFE_SUM_SIZE_T().

return BUFFER_E;
}

if (sending > sizeof(staticBuffer)) {
myBuffer = (byte*)XMALLOC(sending, ssl->heap,
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