| Message ID | 20240613022538.121631-1-llfamsec@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] ocfs2: add bounds checking to ocfs2_check_dir_entry() | expand |
On 6/13/24 10:25 AM, lei lu wrote: > This adds sanity checks for ocfs2_dir_entry to make sure all members of > ocfs2_dir_entry don't stray beyond valid memory region. > > Signed-off-by: lei lu <llfamsec@gmail.com> > --- > fs/ocfs2/dir.c | 32 ++++++++++++++++++++------------ > 1 file changed, 20 insertions(+), 12 deletions(-) > > diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c > index d620d4c53c6f..7aa4a5733993 100644 > --- a/fs/ocfs2/dir.c > +++ b/fs/ocfs2/dir.c > @@ -294,13 +294,14 @@ static void ocfs2_dx_dir_name_hash(struct inode *dir, const char *name, int len, > * 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"; > @@ -308,6 +309,11 @@ static int ocfs2_check_dir_entry(struct inode * dir, > 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(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"; > else if (unlikely( > ((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)) > error_msg = "directory entry across blocks"; > @@ -352,16 +358,16 @@ static inline int ocfs2_search_dirblock(struct buffer_head *bh, > 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, de_buf, bytes, offset)) { > ret = -1; > goto bail; > } > @@ -1138,7 +1144,7 @@ static int __ocfs2_delete_entry(handle_t *handle, struct inode *dir, > 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; > @@ -1635,7 +1641,7 @@ 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; > } > @@ -1774,7 +1780,8 @@ static int ocfs2_dir_foreach_blk_id(struct inode *inode, > } > > 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; > @@ -1867,7 +1874,8 @@ static int ocfs2_dir_foreach_blk_el(struct inode *inode, > 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, > + i_size_read(inode), offset)) { Seems we have to use sb->s_blocksize instead i_size_read(inode) here. This is not the case of inline data. > /* On error, skip the f_pos to the > next block. */ > ctx->pos = (ctx->pos | (sb->s_blocksize - 1)) + 1; > @@ -3359,7 +3367,7 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh, > 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, de_buf, i_size_read(dir), offset)) { > ret = -ENOENT; > goto out; > } > @@ -3441,7 +3449,7 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name, > /* 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, sb->s_blocksize, offset)) { Can use blocksize directly since it is already defined. Thanks, Joseph > status = -ENOENT; > goto bail; > }
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c index d620d4c53c6f..7aa4a5733993 100644 --- a/fs/ocfs2/dir.c +++ b/fs/ocfs2/dir.c @@ -294,13 +294,14 @@ static void ocfs2_dx_dir_name_hash(struct inode *dir, const char *name, int len, * 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"; @@ -308,6 +309,11 @@ static int ocfs2_check_dir_entry(struct inode * dir, 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(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"; else if (unlikely( ((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)) error_msg = "directory entry across blocks"; @@ -352,16 +358,16 @@ static inline int ocfs2_search_dirblock(struct buffer_head *bh, 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, de_buf, bytes, offset)) { ret = -1; goto bail; } @@ -1138,7 +1144,7 @@ static int __ocfs2_delete_entry(handle_t *handle, struct inode *dir, 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; @@ -1635,7 +1641,7 @@ 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; } @@ -1774,7 +1780,8 @@ static int ocfs2_dir_foreach_blk_id(struct inode *inode, } 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; @@ -1867,7 +1874,8 @@ static int ocfs2_dir_foreach_blk_el(struct inode *inode, 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, + i_size_read(inode), offset)) { /* On error, skip the f_pos to the next block. */ ctx->pos = (ctx->pos | (sb->s_blocksize - 1)) + 1; @@ -3359,7 +3367,7 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh, 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, de_buf, i_size_read(dir), offset)) { ret = -ENOENT; goto out; } @@ -3441,7 +3449,7 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name, /* 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, sb->s_blocksize, offset)) { status = -ENOENT; goto bail; }
This adds sanity checks for ocfs2_dir_entry to make sure all members of ocfs2_dir_entry don't stray beyond valid memory region. Signed-off-by: lei lu <llfamsec@gmail.com> --- fs/ocfs2/dir.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-)