From: Randall Huang huangrandall@google.com
mainline inclusion from mainline-v5.5-rc1 commit 688078e7f36c293dae25b338ddc9e0a2790f6e06 category: bugfix bugzilla: 13690 CVE: CVE-2020-0067
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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 Signed-off-by: Yang Yingliang yangyingliang@huawei.com [yyl: replace f2fs_err() with f2fs_msg()]
Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/f2fs/xattr.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index 1dae74f..90d0d30 100644 --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -538,8 +538,9 @@ int f2fs_getxattr(struct inode *inode, int index, const char *name, 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 +559,15 @@ 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(F2FS_I_SB(inode)->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;