From: Randall Huang Date: Fri, 18 Oct 2019 14:56:22 +0800 Subject: f2fs: fix to avoid memory leakage in f2fs_listxattr Origin: https://git.kernel.org/linus/688078e7f36c293dae25b338ddc9e0a2790f6e06 Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2020-0067 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 Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim [bwh: Backported to 4.19: Use f2fs_msg() instead of f2fs_err()] Signed-off-by: Ben Hutchings Signed-off-by: Sasha Levin --- fs/f2fs/xattr.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index 1dae74f7cccac..201e9da1692a4 100644 --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -538,8 +538,9 @@ 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; @@ -549,6 +550,8 @@ ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 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); @@ -556,6 +559,16 @@ ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 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; -- 2.20.1