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e2fsck: fix f_baddotdir failure on big-endian systems

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Commit 63f44aafb1 ("e2fsck: fix ".." more gracefully if possible")
changed the check_dot() function to try to avoid resetting the '..'
entry when the '.' entry is too large..  But if we do that, then on
big-endian systems, we need to try byte swapping the rest of the
directory entries, or else the f_baddotdir test will fail on
big-endian systems.

Also add a check to avoid UBSAN warning when there is not enough space
at the end of the directory block for a directory entry, and so we can
potentially overflow some pointer arithmetic when trying to byte swap
the remainder of the (negative) space in the directory block.

Fixes: 63f44aafb1 ("e2fsck: fix ".." more gracefully if possible")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2021-07-28 13:51:13 -04:00
parent 496669a290
commit 225e5d093b
1 changed files with 13 additions and 5 deletions
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18
e2fsck/pass2.c
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@ -458,6 +458,12 @@ static int check_dot(e2fsck_t ctx,
ext2fs_dirent_set_name_len(nextdir, 0);
ext2fs_dirent_set_file_type(nextdir,
ftype);
#ifdef WORDS_BIGENDIAN
} else {
(void) ext2fs_dirent_swab_in2(ctx->fs,
(char *) nextdir,
ctx->fs->blocksize - 12, 0);
#endif
}
status = 1;
}
@ -1370,12 +1376,14 @@ skip_checksum:
hash_in_dirent);
#ifdef WORDS_BIGENDIAN
if (need_reswab) {
unsigned int len;
(void) ext2fs_get_rec_len(fs,
dirent, &rec_len);
ext2fs_dirent_swab_in2(fs,
((char *)dirent) + offset + rec_len,
max_block_size - offset - rec_len,
0);
dirent, &len);
len += offset;
if (max_block_size > len)
ext2fs_dirent_swab_in2(fs,
((char *)dirent) + len, max_block_size - len, 0);
}
#endif
dir_modified++;