libopendkim: fix strlcpy destination size in dkim_diffheaders()#291
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thegushi wants to merge 1 commit into
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libopendkim: fix strlcpy destination size in dkim_diffheaders()#291thegushi wants to merge 1 commit into
thegushi wants to merge 1 commit into
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Pass MAXHEADERS (the actual allocation size of dkim_zdecode) as the strlcpy size argument instead of strlen(z) (source size). Using the source length silently truncates the copy by one character and suppresses the compiler warning incorrectly. Also fix the adjacent error message which reported strlen(z) bytes when MAXHEADERS bytes are actually allocated. Fixes trusteddomainproject#86.
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Fixes #86.
The
strlcpycall indkim_diffheaders()was passingstrlen(z)(the source length) as the size argument instead of the destination buffer size.strlcpyexpects the size of the destination, so using the source length would silently truncate the copy by one character and is what triggers the compiler warning.The buffer is allocated with
MAXHEADERS(32768 bytes), so the correct size argument isMAXHEADERS.Also fixed the adjacent allocation error message which was reporting
strlen(z)bytes whenMAXHEADERSbytes are actually being allocated.Neither the original code nor the proposed patch in the issue was correct:
strlen(z)): copies at moststrlen(z) - 1characters, truncating by onestrlen(dkim->dkim_zdecode)): on freshly-allocated memory this isstrlen("") = 0, copying nothingMAXHEADERS, matching theDKIM_MALLOC(dkim, MAXHEADERS)on the line above