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| author | Sergey Poznyakoff <gray@gnu.org> | 2018-12-21 14:18:14 +0200 |
|---|---|---|
| committer | Sergey Poznyakoff <gray@gnu.org> | 2018-12-21 14:39:49 +0200 |
| commit | 3c2a2cd94d3b062aa5bf850b82364039ec9c6029 (patch) | |
| tree | 3bce2a1b74cf6d89772f612c37cc86f52a0d137d | |
| parent | ea3aea06f1da077dbb4092672dc7e8768ae4f84e (diff) | |
| download | tar-3c2a2cd94d3b062aa5bf850b82364039ec9c6029.tar.gz tar-3c2a2cd94d3b062aa5bf850b82364039ec9c6029.tar.bz2 | |
Disallow modifications to the global pax extended header in update mode.
Updating global headers in update mode is not possible, because:
1) If the original archive was not in PAX format, writing the
global header would overwrite first member header (and eventually
data blocks) in the archive.
2) Otherwise, using the --pax-option can make the updated header
occupy more blocks than the original one, which would lead to the
same effect as in 1.
This also fixes
http://lists.gnu.org/archive/html/bug-tar/2018-12/msg00007.html
* src/xheader.c (xheader_forbid_global): New function.
* src/common.h (xheader_forbid_global): New prototype.
* src/update.c (update_archive): Use xheader_forbid_global, instead
of trying to write global extended header record.
| -rw-r--r-- | src/common.h | 1 | ||||
| -rw-r--r-- | src/update.c | 2 | ||||
| -rw-r--r-- | src/xheader.c | 8 |
3 files changed, 10 insertions, 1 deletions
diff --git a/src/common.h b/src/common.h index 32e6f8bd..885169fb 100644 --- a/src/common.h +++ b/src/common.h @@ -836,6 +836,7 @@ void xheader_store (char const *keyword, struct tar_stat_info *st, void xheader_read (struct xheader *xhdr, union block *header, off_t size); void xheader_write (char type, char *name, time_t t, struct xheader *xhdr); void xheader_write_global (struct xheader *xhdr); +void xheader_forbid_global (void); void xheader_finish (struct xheader *hdr); void xheader_destroy (struct xheader *hdr); char *xheader_xhdr_name (struct tar_stat_info *st); diff --git a/src/update.c b/src/update.c index 2f823e45..4aa4ac6a 100644 --- a/src/update.c +++ b/src/update.c @@ -111,7 +111,7 @@ update_archive (void) name_gather (); open_archive (ACCESS_UPDATE); - buffer_write_global_xheader (); + xheader_forbid_global (); while (!found_end) { diff --git a/src/xheader.c b/src/xheader.c index e9385022..010cab79 100644 --- a/src/xheader.c +++ b/src/xheader.c @@ -469,6 +469,14 @@ xheader_write_global (struct xheader *xhdr) } } +/* Forbid modifications of the global extended header */ +void +xheader_forbid_global (void) +{ + if (keyword_global_override_list) + USAGE_ERROR ((0, 0, _("can't update global extended header record"))); +} + void xheader_xattr_init (struct tar_stat_info *st) { |