From 4fbb584a0e6ee086d6b30936c7124c687b3e977f Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Fri, 24 Nov 2006 14:55:23 +0000 Subject: tar: cry murder and bail out if file shrinks under us while we tar it up --- archival/tar.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'archival') diff --git a/archival/tar.c b/archival/tar.c index 6aaa42273..99c4adb6a 100644 --- a/archival/tar.c +++ b/archival/tar.c @@ -59,7 +59,7 @@ struct TarHeader { /* byte offset */ typedef struct TarHeader TarHeader; /* -** writeTarFile(), writeFileToTarball(), and writeTarHeader() are +** writeTarFile(), writeFileToTarball(), and writeTarHeader() are ** the only functions that deal with the HardLinkInfo structure. ** Even these functions use the xxxHardLinkInfo() functions. */ @@ -397,7 +397,17 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf, off_t readSize = 0; /* write the file to the archive */ - readSize = bb_copyfd_eof(inputFileFd, tbInfo->tarFd); + readSize = bb_copyfd_size(inputFileFd, tbInfo->tarFd, statbuf->st_size); + if (readSize != statbuf->st_size) { + /* Deadly. We record size into header first, */ + /* and then write out file. If file shrinks in between, */ + /* tar will be corrupted. So bail out. */ + /* NB: GNU tar 1.16 warns and pads with zeroes */ + /* or even seeks back and updates header */ + bb_error_msg_and_die("short read from %s", fileName); + } + /* Check that file did not grow in between? */ + /* if (safe_read(inputFileFd,1) == 1) warn but continue? */ close(inputFileFd); /* Pad the file up to the tar block size */ -- cgit v1.2.3