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authorDenys Vlasenko <vda.linux@googlemail.com>2016-04-17 21:05:34 +0200
committerDenys Vlasenko <vda.linux@googlemail.com>2016-04-17 21:05:34 +0200
commit0ccf52a9fb9fa2f76eacbb6f1ef8419220557a40 (patch)
treeb1255e1f73791c91f5885ece2f75617385d3ed23
parent84ba50c32f7dbfccddd5c5ca34d48d97c3f72193 (diff)
downloadbusybox-0ccf52a9fb9fa2f76eacbb6f1ef8419220557a40.tar.gz
unzip: fix a case where we find wrong CDE. Closes 8821
function old new delta unzip_main 2472 2490 +18 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--archival/unzip.c43
1 files changed, 35 insertions, 8 deletions
diff --git a/archival/unzip.c b/archival/unzip.c
index f41ab6f44..b0a6ca836 100644
--- a/archival/unzip.c
+++ b/archival/unzip.c
@@ -45,6 +45,12 @@
#include "libbb.h"
#include "bb_archive.h"
+#if 0
+# define dbg(...) bb_error_msg(__VA_ARGS__)
+#else
+# define dbg(...) ((void)0)
+#endif
+
enum {
#if BB_BIG_ENDIAN
ZIP_FILEHEADER_MAGIC = 0x504b0304,
@@ -193,15 +199,17 @@ static uint32_t find_cdf_offset(void)
unsigned char *p;
off_t end;
unsigned char *buf = xzalloc(PEEK_FROM_END);
+ uint32_t found;
end = xlseek(zip_fd, 0, SEEK_END);
end -= PEEK_FROM_END;
if (end < 0)
end = 0;
- xlseek(zip_fd, end, SEEK_SET);
+ dbg("Looking for cdf_offset starting from 0x%"OFF_FMT"x", end);
+ xlseek(zip_fd, end, SEEK_SET);
full_read(zip_fd, buf, PEEK_FROM_END);
- cde_header.formatted.cdf_offset = BAD_CDF_OFFSET;
+ found = BAD_CDF_OFFSET;
p = buf;
while (p <= buf + PEEK_FROM_END - CDE_HEADER_LEN - 4) {
if (*p != 'P') {
@@ -220,14 +228,25 @@ static uint32_t find_cdf_offset(void)
/*
* I've seen .ZIP files with seemingly valid CDEs
* where cdf_offset points past EOF - ??
- * Ignore such CDEs:
+ * This check ignores such CDEs:
*/
- if (cde_header.formatted.cdf_offset < end + (p - buf))
- break;
- cde_header.formatted.cdf_offset = BAD_CDF_OFFSET;
+ if (cde_header.formatted.cdf_offset < end + (p - buf)) {
+ found = cde_header.formatted.cdf_offset;
+ dbg("Possible cdf_offset:0x%x at 0x%"OFF_FMT"x",
+ (unsigned)found, end + (p-3 - buf));
+ dbg(" cdf_offset+cdf_size:0x%x",
+ (unsigned)(found + SWAP_LE32(cde_header.formatted.cdf_size)));
+ /*
+ * We do not "break" here because only the last CDE is valid.
+ * I've seen a .zip archive which contained a .zip file,
+ * uncompressed, and taking the first CDE was using
+ * the CDE inside that file!
+ */
+ }
}
free(buf);
- return cde_header.formatted.cdf_offset;
+ dbg("Found cdf_offset:0x%x", (unsigned)found);
+ return found;
};
static uint32_t read_next_cdf(uint32_t cdf_offset, cdf_header_t *cdf_ptr)
@@ -240,9 +259,13 @@ static uint32_t read_next_cdf(uint32_t cdf_offset, cdf_header_t *cdf_ptr)
cdf_offset = find_cdf_offset();
if (cdf_offset != BAD_CDF_OFFSET) {
+ dbg("Reading CDF at 0x%x", (unsigned)cdf_offset);
xlseek(zip_fd, cdf_offset + 4, SEEK_SET);
xread(zip_fd, cdf_ptr->raw, CDF_HEADER_LEN);
FIX_ENDIANNESS_CDF(*cdf_ptr);
+ dbg("file_name_length:%u", (unsigned)cdf_ptr->formatted.file_name_length);
+ dbg("extra_field_length:%u", (unsigned)cdf_ptr->formatted.extra_field_length);
+ dbg("file_comment_length:%u", (unsigned)cdf_ptr->formatted.file_comment_length);
cdf_offset += 4 + CDF_HEADER_LEN
+ cdf_ptr->formatted.file_name_length
+ cdf_ptr->formatted.extra_field_length
@@ -532,11 +555,14 @@ int unzip_main(int argc, char **argv)
/* Check magic number */
xread(zip_fd, &magic, 4);
/* Central directory? It's at the end, so exit */
- if (magic == ZIP_CDF_MAGIC)
+ if (magic == ZIP_CDF_MAGIC) {
+ dbg("got ZIP_CDF_MAGIC");
break;
+ }
#if ENABLE_DESKTOP
/* Data descriptor? It was a streaming file, go on */
if (magic == ZIP_DD_MAGIC) {
+ dbg("got ZIP_DD_MAGIC");
/* skip over duplicate crc32, cmpsize and ucmpsize */
unzip_skip(3 * 4);
continue;
@@ -544,6 +570,7 @@ int unzip_main(int argc, char **argv)
#endif
if (magic != ZIP_FILEHEADER_MAGIC)
bb_error_msg_and_die("invalid zip magic %08X", (int)magic);
+ dbg("got ZIP_FILEHEADER_MAGIC");
/* Read the file header */
xread(zip_fd, zip_header.raw, ZIP_HEADER_LEN);