diff options
| -rw-r--r-- | archival/libarchive/get_header_ar.c | 32 |
1 files changed, 20 insertions, 12 deletions
diff --git a/archival/libarchive/get_header_ar.c b/archival/libarchive/get_header_ar.c index 23c4124..f655585 100644 --- a/archival/libarchive/get_header_ar.c +++ b/archival/libarchive/get_header_ar.c @@ -8,11 +8,19 @@ #include "bb_archive.h" #include "ar.h" -static unsigned read_num(const char *str, int base) +/* WARNING: Clobbers str[len], so fields must be read in reverse order! */ +static unsigned read_num(char *str, int base, int len) { + int err; + + /* ar fields are fixed length text strings (padded with spaces). + * Ensure bb_strtou doesn't read past the field in case the full + * width is used. */ + str[len] = 0; + /* This code works because * on misformatted numbers bb_strtou returns all-ones */ - int err = bb_strtou(str, NULL, base); + err = bb_strtou(str, NULL, base); if (err == -1) bb_error_msg_and_die("invalid ar header"); return err; @@ -51,11 +59,8 @@ char FAST_FUNC get_header_ar(archive_handle_t *archive_handle) if (ar.formatted.magic[0] != '`' || ar.formatted.magic[1] != '\n') bb_error_msg_and_die("invalid ar header"); - /* FIXME: more thorough routine would be in order here - * (we have something like that in tar) - * but for now we are lax. */ - ar.formatted.magic[0] = '\0'; /* else 4G-2 file will have size="4294967294`\n..." */ - typed->size = size = read_num(ar.formatted.size, 10); + typed->size = size = read_num(ar.formatted.size, 10, + sizeof(ar.formatted.size)); /* special filenames have '/' as the first character */ if (ar.formatted.name[0] == '/') { @@ -86,11 +91,13 @@ char FAST_FUNC get_header_ar(archive_handle_t *archive_handle) /* Only size is always present, the rest may be missing in * long filename pseudo file. Thus we decode the rest * after dealing with long filename pseudo file. + * Note that the fields MUST be read in reverse order as + * read_num() clobbers the next byte after the field! */ - typed->mode = read_num(ar.formatted.mode, 8); - typed->mtime = read_num(ar.formatted.date, 10); - typed->uid = read_num(ar.formatted.uid, 10); - typed->gid = read_num(ar.formatted.gid, 10); + typed->mode = read_num(ar.formatted.mode, 8, sizeof(ar.formatted.mode)); + typed->gid = read_num(ar.formatted.gid, 10, sizeof(ar.formatted.gid)); + typed->uid = read_num(ar.formatted.uid, 10, sizeof(ar.formatted.uid)); + typed->mtime = read_num(ar.formatted.date, 10, sizeof(ar.formatted.date)); #if ENABLE_FEATURE_AR_LONG_FILENAMES if (ar.formatted.name[0] == '/') { @@ -98,7 +105,8 @@ char FAST_FUNC get_header_ar(archive_handle_t *archive_handle) /* The number after the '/' indicates the offset in the ar data section * (saved in ar_long_names) that conatains the real filename */ - long_offset = read_num(&ar.formatted.name[1], 10); + long_offset = read_num(&ar.formatted.name[1], 10, + sizeof(ar.formatted.name) - 1); if (long_offset >= ar_long_name_size) { bb_error_msg_and_die("can't resolve long filename"); } |