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| author | Paul Eggert <eggert@cs.ucla.edu> | 2010-10-27 22:25:18 -0700 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2010-10-27 22:31:16 -0700 |
| commit | b8feb2b14247d76200fd53607d3613c82b6e5b81 (patch) | |
| tree | 1a4285963b922162562929c82b9e0b8b357e153d | |
| parent | 3fe59ed5ef44d61d313e711b8920f8285792d3b2 (diff) | |
| download | tar-b8feb2b14247d76200fd53607d3613c82b6e5b81.tar.gz | |
tar: don't cross struct member boundaries with OLDGNU_MAGIC
* src/create.c (write_gnu_long_link, start_header): Access
header->buffer + offsetof (struct posix_header, magic), instead of
header->header.magic, when reading or writing the OLDGNU_MAGIC
pattern. The code violates the C standard without this change,
and GCC warns about this if fortify checking is enabled. It's not
a bug on traditional (i.e., non-debugging) platforms, but it does
violate the C standard so it should be fixed. Problem originally
reported by John Emil Karlson in
<http://lists.gnu.org/archive/html/bug-tar/2010-04/msg00023.html>.
* src/list.c (decode_header): Likewise.
| -rw-r--r-- | src/create.c | 6 | ||||
| -rw-r--r-- | src/list.c | 6 |
2 files changed, 8 insertions, 4 deletions
diff --git a/src/create.c b/src/create.c index 05af0d90..a1e90a33 100644 --- a/src/create.c +++ b/src/create.c @@ -562,7 +562,8 @@ write_gnu_long_link (struct tar_stat_info *st, const char *p, char type) GNAME_TO_CHARS (tmpname, header->header.gname); free (tmpname); - strcpy (header->header.magic, OLDGNU_MAGIC); + strcpy (header->buffer + offsetof (struct posix_header, magic), + OLDGNU_MAGIC); header->header.typeflag = type; finish_header (st, header, -1); @@ -899,7 +900,8 @@ start_header (struct tar_stat_info *st) case OLDGNU_FORMAT: case GNU_FORMAT: /*FIXME?*/ /* Overwrite header->header.magic and header.version in one blow. */ - strcpy (header->header.magic, OLDGNU_MAGIC); + strcpy (header->buffer + offsetof (struct posix_header, magic), + OLDGNU_MAGIC); break; case POSIX_FORMAT: @@ -122,7 +122,7 @@ transform_stat_info (int typeflag, struct tar_stat_info *stat_info) if (typeflag == GNUTYPE_VOLHDR) /* Name transformations don't apply to volume headers. */ return; - + transform_member_name (&stat_info->file_name, XFORM_REGFILE); switch (typeflag) { @@ -592,7 +592,9 @@ decode_header (union block *header, struct tar_stat_info *stat_info, else format = USTAR_FORMAT; } - else if (strcmp (header->header.magic, OLDGNU_MAGIC) == 0) + else if (strcmp (header->buffer + offsetof (struct posix_header, magic), + OLDGNU_MAGIC) + == 0) format = hbits ? OLDGNU_FORMAT : GNU_FORMAT; else format = V7_FORMAT; |