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Improve unzip's handling of stream ZIP files

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Search harder for the ZIP magic numbers at the end of a file by checking
16 KiB from the end instead of just 1 KiB.  ZIP files with long comments
(such as certain cryptographically signed files) or those sitting in a
wrapper could have more than 1 KiB of data after the magic numbers, so
they couldn't be read.

Signed-off-by: Dan Fandrich <dan@coneharvesters.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Dan Fandrich 2010-06-17 21:39:44 -07:00 committed by Denys Vlasenko
parent eafc6956f6
commit b76f18d331
1 changed files with 9 additions and 4 deletions
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13
archival/unzip.c
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@ -150,23 +150,26 @@ enum { zip_fd = 3 };
#if ENABLE_DESKTOP
#define PEEK_FROM_END 16384
/* NB: does not preserve file position! */
static uint32_t find_cdf_offset(void)
{
unsigned char buf[1024];
cde_header_t cde_header;
unsigned char *p;
off_t end;
unsigned char *buf = xzalloc(PEEK_FROM_END);
end = xlseek(zip_fd, 0, SEEK_END);
end -= 1024;
end -= PEEK_FROM_END;
if (end < 0)
end = 0;
xlseek(zip_fd, end, SEEK_SET);
full_read(zip_fd, buf, 1024);
full_read(zip_fd, buf, PEEK_FROM_END);
p = buf;
while (p <= buf + 1024 - CDE_HEADER_LEN - 4) {
while (p <= buf + PEEK_FROM_END - CDE_HEADER_LEN - 4) {
if (*p != 'P') {
p++;
continue;
@ -180,8 +183,10 @@ static uint32_t find_cdf_offset(void)
/* we found CDE! */
memcpy(cde_header.raw, p + 1, CDE_HEADER_LEN);
FIX_ENDIANNESS_CDE(cde_header);
free(buf);
return cde_header.formatted.cdf_offset;
}
//free(buf);
bb_error_msg_and_die("can't find file table");
};