From: Jan Kara jack@suse.cz

stable inclusion from stable-v4.19.217 commit b0ddff8d68f2e43857a84dce54c3deab181c8ae1 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RD2M CVE: CVE-2021-47478

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit e96a1866b40570b5950cda8602c2819189c62a48 upstream.

When isofs image is suitably corrupted isofs_read_inode() can read data beyond the end of buffer. Sanity-check the directory entry length before using it.

Reported-and-tested-by: syzbot+6fc7fb214625d82af7d1@syzkaller.appspotmail.com CC: stable@vger.kernel.org Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Guo Mengqi guomengqi3@huawei.com --- fs/isofs/inode.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c index 488a9e7f8f66..f77a7f19b0db 100644 --- a/fs/isofs/inode.c +++ b/fs/isofs/inode.c @@ -1327,6 +1327,8 @@ static int isofs_read_inode(struct inode *inode, int relocated)

de = (struct iso_directory_record *) (bh->b_data + offset); de_len = *(unsigned char *) de; + if (de_len < sizeof(struct iso_directory_record)) + goto fail;

if (offset + de_len > bufsize) { int frag1 = bufsize - offset;