4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: lei lu llfamsec@gmail.com
commit 255547c6bb8940a97eea94ef9d464ea5967763fb upstream.
This adds sanity checks for ocfs2_dir_entry to make sure all members of ocfs2_dir_entry don't stray beyond valid memory region.
Link: https://lkml.kernel.org/r/20240626104433.163270-1-llfamsec@gmail.com Signed-off-by: lei lu llfamsec@gmail.com Reviewed-by: Heming Zhao heming.zhao@suse.com Reviewed-by: Joseph Qi joseph.qi@linux.alibaba.com Cc: Mark Fasheh mark@fasheh.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Cc: Changwei Ge gechangwei@live.cn Cc: Gang He ghe@suse.com Cc: Jun Piao piaojun@huawei.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ocfs2/dir.c | 46 +++++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 17 deletions(-)
--- a/fs/ocfs2/dir.c +++ b/fs/ocfs2/dir.c @@ -314,13 +314,16 @@ out: * bh passed here can be an inode block or a dir data block, depending * on the inode inline data flag. */ -static int ocfs2_check_dir_entry(struct inode * dir, - struct ocfs2_dir_entry * de, - struct buffer_head * bh, +static int ocfs2_check_dir_entry(struct inode *dir, + struct ocfs2_dir_entry *de, + struct buffer_head *bh, + char *buf, + unsigned int size, unsigned long offset) { const char *error_msg = NULL; const int rlen = le16_to_cpu(de->rec_len); + const unsigned long next_offset = ((char *) de - buf) + rlen;
if (unlikely(rlen < OCFS2_DIR_REC_LEN(1))) error_msg = "rec_len is smaller than minimal"; @@ -328,9 +331,11 @@ static int ocfs2_check_dir_entry(struct error_msg = "rec_len % 4 != 0"; else if (unlikely(rlen < OCFS2_DIR_REC_LEN(de->name_len))) error_msg = "rec_len is too small for name_len"; - else if (unlikely( - ((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)) - error_msg = "directory entry across blocks"; + else if (unlikely(next_offset > size)) + error_msg = "directory entry overrun"; + else if (unlikely(next_offset > size - OCFS2_DIR_REC_LEN(1)) && + next_offset != size) + error_msg = "directory entry too close to end";
if (unlikely(error_msg != NULL)) mlog(ML_ERROR, "bad entry in directory #%llu: %s - " @@ -372,16 +377,17 @@ static inline int ocfs2_search_dirblock( de_buf = first_de; dlimit = de_buf + bytes;
- while (de_buf < dlimit) { + while (de_buf < dlimit - OCFS2_DIR_MEMBER_LEN) { /* this code is executed quadratically often */ /* do minimal checking `by hand' */
de = (struct ocfs2_dir_entry *) de_buf;
- if (de_buf + namelen <= dlimit && + if (de->name + namelen <= dlimit && ocfs2_match(namelen, name, de)) { /* found a match - just to be sure, do a full check */ - if (!ocfs2_check_dir_entry(dir, de, bh, offset)) { + if (!ocfs2_check_dir_entry(dir, de, bh, first_de, + bytes, offset)) { ret = -1; goto bail; } @@ -1158,7 +1164,7 @@ static int __ocfs2_delete_entry(handle_t pde = NULL; de = (struct ocfs2_dir_entry *) first_de; while (i < bytes) { - if (!ocfs2_check_dir_entry(dir, de, bh, i)) { + if (!ocfs2_check_dir_entry(dir, de, bh, first_de, bytes, i)) { status = -EIO; mlog_errno(status); goto bail; @@ -1658,7 +1664,8 @@ int __ocfs2_add_entry(handle_t *handle, /* These checks should've already been passed by the * prepare function, but I guess we can leave them * here anyway. */ - if (!ocfs2_check_dir_entry(dir, de, insert_bh, offset)) { + if (!ocfs2_check_dir_entry(dir, de, insert_bh, data_start, + size, offset)) { retval = -ENOENT; goto bail; } @@ -1796,7 +1803,8 @@ static int ocfs2_dir_foreach_blk_id(stru }
de = (struct ocfs2_dir_entry *) (data->id_data + ctx->pos); - if (!ocfs2_check_dir_entry(inode, de, di_bh, ctx->pos)) { + if (!ocfs2_check_dir_entry(inode, de, di_bh, (char *)data->id_data, + i_size_read(inode), ctx->pos)) { /* On error, skip the f_pos to the end. */ ctx->pos = i_size_read(inode); break; @@ -1893,7 +1901,8 @@ static int ocfs2_dir_foreach_blk_el(stru while (ctx->pos < i_size_read(inode) && offset < sb->s_blocksize) { de = (struct ocfs2_dir_entry *) (bh->b_data + offset); - if (!ocfs2_check_dir_entry(inode, de, bh, offset)) { + if (!ocfs2_check_dir_entry(inode, de, bh, bh->b_data, + sb->s_blocksize, offset)) { /* On error, skip the f_pos to the next block. */ ctx->pos = (ctx->pos | (sb->s_blocksize - 1)) + 1; @@ -3369,7 +3378,7 @@ static int ocfs2_find_dir_space_id(struc struct super_block *sb = dir->i_sb; struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data; struct ocfs2_dir_entry *de, *last_de = NULL; - char *de_buf, *limit; + char *first_de, *de_buf, *limit; unsigned long offset = 0; unsigned int rec_len, new_rec_len, free_space = dir->i_sb->s_blocksize;
@@ -3382,14 +3391,16 @@ static int ocfs2_find_dir_space_id(struc else free_space = dir->i_sb->s_blocksize - i_size_read(dir);
- de_buf = di->id2.i_data.id_data; + first_de = di->id2.i_data.id_data; + de_buf = first_de; limit = de_buf + i_size_read(dir); rec_len = OCFS2_DIR_REC_LEN(namelen);
while (de_buf < limit) { de = (struct ocfs2_dir_entry *)de_buf;
- if (!ocfs2_check_dir_entry(dir, de, di_bh, offset)) { + if (!ocfs2_check_dir_entry(dir, de, di_bh, first_de, + i_size_read(dir), offset)) { ret = -ENOENT; goto out; } @@ -3471,7 +3482,8 @@ static int ocfs2_find_dir_space_el(struc /* move to next block */ de = (struct ocfs2_dir_entry *) bh->b_data; } - if (!ocfs2_check_dir_entry(dir, de, bh, offset)) { + if (!ocfs2_check_dir_entry(dir, de, bh, bh->b_data, blocksize, + offset)) { status = -ENOENT; goto bail; }