| 1 | Backport of commit: |
| 2 | https://git.busybox.net/busybox/commit/?id=0ccf52a9fb9fa2f76eacbb6f1ef8419220557a40 |
| 3 | for issue: |
| 4 | https://bugs.busybox.net/show_bug.cgi?id=8821 |
| 5 | |
| 6 | diff --git a/archival/unzip.c b/archival/unzip.c |
| 7 | index f41ab6f..b0a6ca8 100644 |
| 8 | --- a/archival/unzip.c |
| 9 | +++ b/archival/unzip.c |
| 10 | @@ -45,6 +45,12 @@ |
| 11 | #include "libbb.h" |
| 12 | #include "bb_archive.h" |
| 13 | |
| 14 | +#if 0 |
| 15 | +# define dbg(...) bb_error_msg(__VA_ARGS__) |
| 16 | +#else |
| 17 | +# define dbg(...) ((void)0) |
| 18 | +#endif |
| 19 | + |
| 20 | enum { |
| 21 | #if BB_BIG_ENDIAN |
| 22 | ZIP_FILEHEADER_MAGIC = 0x504b0304, |
| 23 | @@ -193,15 +199,17 @@ static uint32_t find_cdf_offset(void) |
| 24 | unsigned char *p; |
| 25 | off_t end; |
| 26 | unsigned char *buf = xzalloc(PEEK_FROM_END); |
| 27 | + uint32_t found; |
| 28 | |
| 29 | end = xlseek(zip_fd, 0, SEEK_END); |
| 30 | end -= PEEK_FROM_END; |
| 31 | if (end < 0) |
| 32 | end = 0; |
| 33 | - xlseek(zip_fd, end, SEEK_SET); |
| 34 | + dbg("Looking for cdf_offset starting from 0x%"OFF_FMT"x", end); |
| 35 | + xlseek(zip_fd, end, SEEK_SET); |
| 36 | full_read(zip_fd, buf, PEEK_FROM_END); |
| 37 | |
| 38 | - cde_header.formatted.cdf_offset = BAD_CDF_OFFSET; |
| 39 | + found = BAD_CDF_OFFSET; |
| 40 | p = buf; |
| 41 | while (p <= buf + PEEK_FROM_END - CDE_HEADER_LEN - 4) { |
| 42 | if (*p != 'P') { |
| 43 | @@ -220,14 +228,25 @@ static uint32_t find_cdf_offset(void) |
| 44 | /* |
| 45 | * I've seen .ZIP files with seemingly valid CDEs |
| 46 | * where cdf_offset points past EOF - ?? |
| 47 | - * Ignore such CDEs: |
| 48 | + * This check ignores such CDEs: |
| 49 | */ |
| 50 | - if (cde_header.formatted.cdf_offset < end + (p - buf)) |
| 51 | - break; |
| 52 | - cde_header.formatted.cdf_offset = BAD_CDF_OFFSET; |
| 53 | + if (cde_header.formatted.cdf_offset < end + (p - buf)) { |
| 54 | + found = cde_header.formatted.cdf_offset; |
| 55 | + dbg("Possible cdf_offset:0x%x at 0x%"OFF_FMT"x", |
| 56 | + (unsigned)found, end + (p-3 - buf)); |
| 57 | + dbg(" cdf_offset+cdf_size:0x%x", |
| 58 | + (unsigned)(found + SWAP_LE32(cde_header.formatted.cdf_size))); |
| 59 | + /* |
| 60 | + * We do not "break" here because only the last CDE is valid. |
| 61 | + * I've seen a .zip archive which contained a .zip file, |
| 62 | + * uncompressed, and taking the first CDE was using |
| 63 | + * the CDE inside that file! |
| 64 | + */ |
| 65 | + } |
| 66 | } |
| 67 | free(buf); |
| 68 | - return cde_header.formatted.cdf_offset; |
| 69 | + dbg("Found cdf_offset:0x%x", (unsigned)found); |
| 70 | + return found; |
| 71 | }; |
| 72 | |
| 73 | static uint32_t read_next_cdf(uint32_t cdf_offset, cdf_header_t *cdf_ptr) |
| 74 | @@ -240,9 +259,13 @@ static uint32_t read_next_cdf(uint32_t cdf_offset, cdf_header_t *cdf_ptr) |
| 75 | cdf_offset = find_cdf_offset(); |
| 76 | |
| 77 | if (cdf_offset != BAD_CDF_OFFSET) { |
| 78 | + dbg("Reading CDF at 0x%x", (unsigned)cdf_offset); |
| 79 | xlseek(zip_fd, cdf_offset + 4, SEEK_SET); |
| 80 | xread(zip_fd, cdf_ptr->raw, CDF_HEADER_LEN); |
| 81 | FIX_ENDIANNESS_CDF(*cdf_ptr); |
| 82 | + dbg("file_name_length:%u", (unsigned)cdf_ptr->formatted.file_name_length); |
| 83 | + dbg("extra_field_length:%u", (unsigned)cdf_ptr->formatted.extra_field_length); |
| 84 | + dbg("file_comment_length:%u", (unsigned)cdf_ptr->formatted.file_comment_length); |
| 85 | cdf_offset += 4 + CDF_HEADER_LEN |
| 86 | + cdf_ptr->formatted.file_name_length |
| 87 | + cdf_ptr->formatted.extra_field_length |
| 88 | @@ -532,11 +555,14 @@ int unzip_main(int argc, char **argv) |
| 89 | /* Check magic number */ |
| 90 | xread(zip_fd, &magic, 4); |
| 91 | /* Central directory? It's at the end, so exit */ |
| 92 | - if (magic == ZIP_CDF_MAGIC) |
| 93 | + if (magic == ZIP_CDF_MAGIC) { |
| 94 | + dbg("got ZIP_CDF_MAGIC"); |
| 95 | break; |
| 96 | + } |
| 97 | #if ENABLE_DESKTOP |
| 98 | /* Data descriptor? It was a streaming file, go on */ |
| 99 | if (magic == ZIP_DD_MAGIC) { |
| 100 | + dbg("got ZIP_DD_MAGIC"); |
| 101 | /* skip over duplicate crc32, cmpsize and ucmpsize */ |
| 102 | unzip_skip(3 * 4); |
| 103 | continue; |
| 104 | @@ -544,6 +570,7 @@ int unzip_main(int argc, char **argv) |
| 105 | #endif |
| 106 | if (magic != ZIP_FILEHEADER_MAGIC) |
| 107 | bb_error_msg_and_die("invalid zip magic %08X", (int)magic); |
| 108 | + dbg("got ZIP_FILEHEADER_MAGIC"); |
| 109 | |
| 110 | /* Read the file header */ |
| 111 | xread(zip_fd, zip_header.raw, ZIP_HEADER_LEN); |
| 112 | |