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unzip: survive lack of CDF on non-streaming zip files

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2013-07-21 02:31:08 +02:00
parent 1390a010b6
commit 26cd90c7fd
1 changed files with 39 additions and 16 deletions
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55
archival/unzip.c
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@ -172,6 +172,9 @@ enum { zip_fd = 3 };
*/
#define PEEK_FROM_END (64*1024)
/* This value means that we failed to find CDF */
#define BAD_CDF_OFFSET ((uint32_t)0xffffffff)
/* NB: does not preserve file position! */
static uint32_t find_cdf_offset(void)
{
@ -187,6 +190,7 @@ static uint32_t find_cdf_offset(void)
xlseek(zip_fd, end, SEEK_SET);
full_read(zip_fd, buf, PEEK_FROM_END);
cde_header.formatted.cdf_offset = BAD_CDF_OFFSET;
p = buf;
while (p <= buf + PEEK_FROM_END - CDE_HEADER_LEN - 4) {
if (*p != 'P') {
@ -202,11 +206,17 @@ 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;
/*
* I've seen .ZIP files with seemingly valid CDEs
* where cdf_offset points past EOF - ??
* Ignore such CDEs:
*/
if (cde_header.formatted.cdf_offset < end + (p - buf))
break;
cde_header.formatted.cdf_offset = BAD_CDF_OFFSET;
}
//free(buf);
bb_error_msg_and_die("can't find file table");
free(buf);
return cde_header.formatted.cdf_offset;
};
static uint32_t read_next_cdf(uint32_t cdf_offset, cdf_header_t *cdf_ptr)
@ -218,13 +228,15 @@ static uint32_t read_next_cdf(uint32_t cdf_offset, cdf_header_t *cdf_ptr)
if (!cdf_offset)
cdf_offset = find_cdf_offset();
xlseek(zip_fd, cdf_offset + 4, SEEK_SET);
xread(zip_fd, cdf_ptr->raw, CDF_HEADER_LEN);
FIX_ENDIANNESS_CDF(*cdf_ptr);
cdf_offset += 4 + CDF_HEADER_LEN
+ cdf_ptr->formatted.file_name_length
+ cdf_ptr->formatted.extra_field_length
+ cdf_ptr->formatted.file_comment_length;
if (cdf_offset != BAD_CDF_OFFSET) {
xlseek(zip_fd, cdf_offset + 4, SEEK_SET);
xread(zip_fd, cdf_ptr->raw, CDF_HEADER_LEN);
FIX_ENDIANNESS_CDF(*cdf_ptr);
cdf_offset += 4 + CDF_HEADER_LEN
+ cdf_ptr->formatted.file_name_length
+ cdf_ptr->formatted.extra_field_length
+ cdf_ptr->formatted.file_comment_length;
}
xlseek(zip_fd, org, SEEK_SET);
return cdf_offset;
@ -233,8 +245,9 @@ static uint32_t read_next_cdf(uint32_t cdf_offset, cdf_header_t *cdf_ptr)
static void unzip_skip(off_t skip)
{
if (lseek(zip_fd, skip, SEEK_CUR) == (off_t)-1)
bb_copyfd_exact_size(zip_fd, -1, skip);
if (skip != 0)
if (lseek(zip_fd, skip, SEEK_CUR) == (off_t)-1)
bb_copyfd_exact_size(zip_fd, -1, skip);
}
static void unzip_create_leading_dirs(const char *fn)
@ -535,21 +548,31 @@ int unzip_main(int argc, char **argv)
bb_error_msg_and_die("zip flag 1 (encryption) is not supported");
}
{
if (cdf_offset != BAD_CDF_OFFSET) {
cdf_header_t cdf_header;
cdf_offset = read_next_cdf(cdf_offset, &cdf_header);
/*
* Note: cdf_offset can become BAD_CDF_OFFSET after the above call.
*/
if (zip_header.formatted.zip_flags & SWAP_LE16(0x0008)) {
/* 0x0008 - streaming. [u]cmpsize can be reliably gotten
* only from Central Directory. See unzip_doc.txt */
* only from Central Directory. See unzip_doc.txt
*/
zip_header.formatted.crc32 = cdf_header.formatted.crc32;
zip_header.formatted.cmpsize = cdf_header.formatted.cmpsize;
zip_header.formatted.ucmpsize = cdf_header.formatted.ucmpsize;
}
if ((cdf_header.formatted.version_made_by >> 8) == 3) {
/* this archive is created on Unix */
/* This archive is created on Unix */
dir_mode = file_mode = (cdf_header.formatted.external_file_attributes >> 16);
}
}
if (cdf_offset == BAD_CDF_OFFSET
&& (zip_header.formatted.zip_flags & SWAP_LE16(0x0008))
) {
/* If it's a streaming zip, we _require_ CDF */
bb_error_msg_and_die("can't find file table");
}
#endif
/* Read filename */