From: Randall Huang huangrandall@google.com
commit 688078e7f36c293dae25b338ddc9e0a2790f6e06 upstream.
In f2fs_listxattr, there is no boundary check before memcpy e_name to buffer. If the e_name_len is corrupted, unexpected memory contents may be returned to the buffer.
Signed-off-by: Randall Huang huangrandall@google.com Reviewed-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org [bwh: Backported to 4.14: Use f2fs_msg() instead of f2fs_err()] Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/f2fs/xattr.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
--- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -516,8 +516,9 @@ out: ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) { struct inode *inode = d_inode(dentry); + nid_t xnid = F2FS_I(inode)->i_xattr_nid; struct f2fs_xattr_entry *entry; - void *base_addr; + void *base_addr, *last_base_addr; int error = 0; size_t rest = buffer_size;
@@ -527,6 +528,8 @@ ssize_t f2fs_listxattr(struct dentry *de if (error) return error;
+ last_base_addr = (void *)base_addr + XATTR_SIZE(xnid, inode); + list_for_each_xattr(entry, base_addr) { const struct xattr_handler *handler = f2fs_xattr_handler(entry->e_name_index); @@ -534,6 +537,16 @@ ssize_t f2fs_listxattr(struct dentry *de size_t prefix_len; size_t size;
+ if ((void *)(entry) + sizeof(__u32) > last_base_addr || + (void *)XATTR_NEXT_ENTRY(entry) > last_base_addr) { + f2fs_msg(dentry->d_sb, KERN_ERR, + "inode (%lu) has corrupted xattr", + inode->i_ino); + set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_FSCK); + error = -EFSCORRUPTED; + goto cleanup; + } + if (!handler || (handler->list && !handler->list(dentry))) continue;