archive: ustar header checksum is computed unsigned
POSIX.1 (pax) is pretty clear on this: The chksum field shall be the ISO/IEC 646:1991 standard IRV representation of the octal value of the simple sum of all octets in the header logical record. Each octet in the header shall be treated as an unsigned value. These values shall be added to an unsigned integer, initialized to zero, the precision of which is not less than 17 bits. When calculating the checksum, the chksum field is treated as if it were all <space> characters. so is GNU: http://www.gnu.org/software/tar/manual/html_node/Checksumming.html Found by 7zip folks and reported by Rafał Mużyło. Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano committed
Jun 13, 2012 at 10:42 UTC
a5a46eb90f530c731084a57783ca9fdbf1a52163
1 file changed
+3
-3
archive-tar.c
+3
-3
@@ -139,13 +139,13 @@ static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
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static unsigned int ustar_header_chksum(const struct ustar_header *header)
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{
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- const char *p = (const char *)header;
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+ const unsigned char *p = (const unsigned char *)header;
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unsigned int chksum = 0;
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- while (p < header->chksum)
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+ while (p < (const unsigned char *)header->chksum)
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chksum += *p++;
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chksum += sizeof(header->chksum) * ' ';
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p += sizeof(header->chksum);
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- while (p < (const char *)header + sizeof(struct ustar_header))
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+ while (p < (const unsigned char *)header + sizeof(struct ustar_header))
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chksum += *p++;
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return chksum;
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}