From 225e5d093b519f9dbe9fcaacd995426f0e5194f6 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 28 Jul 2021 13:51:13 -0400 Subject: [PATCH] e2fsck: fix f_baddotdir failure on big-endian systems Commit 63f44aafb1f2 ("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: 63f44aafb1f2 ("e2fsck: fix ".." more gracefully if possible") Signed-off-by: Theodore Ts'o --- e2fsck/pass2.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c index f00cb40e..bd974c55 100644 --- a/e2fsck/pass2.c +++ b/e2fsck/pass2.c @@ -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++; -- 2.31.1