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    Subject[PATCH v2] f2fs: fix to avoid memory leakage in f2fs_listxattr
    From
    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>
    ---
    v2:
    relocate sanity check
    ---
    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 181900af2576..296b3189448a 100644
    --- a/fs/f2fs/xattr.c
    +++ b/fs/f2fs/xattr.c
    @@ -539,8 +539,9 @@ 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;

    @@ -550,6 +551,8 @@ 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);
    @@ -557,6 +560,15 @@ 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_err(F2FS_I_SB(inode), "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;

    --
    2.23.0.866.gb869b98d4c-goog
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