diff options
| -rw-r--r-- | archival/unzip.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/archival/unzip.c b/archival/unzip.c index 56a5eb6..8462822 100644 --- a/archival/unzip.c +++ b/archival/unzip.c @@ -41,8 +41,10 @@ enum { #endif }; +#define ZIP_HEADER_LEN 26 + typedef union { - uint8_t raw[26]; + uint8_t raw[ZIP_HEADER_LEN]; struct { uint16_t version; /* 0-1 */ uint16_t flags; /* 2-3 */ @@ -57,8 +59,14 @@ typedef union { } formatted ATTRIBUTE_PACKED; } zip_header_t; +/* Check the offset of the last element, not the length. This leniency + * allows for poor packing, whereby the overall struct may be too long, + * even though the elements are all in the right place. + */ struct BUG_zip_header_must_be_26_bytes { - char BUG_zip_header_must_be_26_bytes[sizeof(zip_header_t) == 26 ? 1 : -1]; + char BUG_zip_header_must_be_26_bytes[ + offsetof(zip_header_t, formatted.extra_len) + 2 == + ZIP_HEADER_LEN ? 1 : -1]; }; #define FIX_ENDIANNESS(zip_header) do { \ @@ -256,7 +264,7 @@ int unzip_main(int argc, char **argv) bb_error_msg_and_die("invalid zip magic %08X", magic); /* Read the file header */ - xread(src_fd, zip_header.raw, sizeof(zip_header)); + xread(src_fd, zip_header.raw, ZIP_HEADER_LEN); FIX_ENDIANNESS(zip_header); if ((zip_header.formatted.method != 0) && (zip_header.formatted.method != 8)) { bb_error_msg_and_die("unsupported method %d", zip_header.formatted.method); |