From: Theodore Ts'o <tytso@mit.edu> stable inclusion from stable-4.19.283 commit 3d7b8fbcd2273e2b9f4c6de5ce2f4c0cd3cb1205 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/ICSDLQ CVE: N/A Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 2220eaf90992c11d888fe771055d4de330385f01 upstream. Normally the extended attributes in the inode body would have been checked when the inode is first opened, but if someone is writing to the block device while the file system is mounted, it's possible for the inode table to get corrupted. Add bounds checking to avoid reading beyond the end of allocated memory if this happens. Reported-by: syzbot+1966db24521e5f6e23f7@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=1966db24521e5f6e23f7 Cc: stable@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Erkun <yangerkun@huawei.com> --- fs/ext4/inline.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c index bb7839bcae35..4e4d4291e0e1 100644 --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -32,6 +32,7 @@ static int get_max_inline_xattr_value_size(struct inode *inode, struct ext4_xattr_ibody_header *header; struct ext4_xattr_entry *entry; struct ext4_inode *raw_inode; + void *end; int free, min_offs; if (!EXT4_INODE_HAS_XATTR_SPACE(inode)) @@ -55,14 +56,23 @@ static int get_max_inline_xattr_value_size(struct inode *inode, raw_inode = ext4_raw_inode(iloc); header = IHDR(inode, raw_inode); entry = IFIRST(header); + end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; /* Compute min_offs. */ - for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { + while (!IS_LAST_ENTRY(entry)) { + void *next = EXT4_XATTR_NEXT(entry); + + if (next >= end) { + EXT4_ERROR_INODE(inode, + "corrupt xattr in inline inode"); + return 0; + } if (!entry->e_value_inum && entry->e_value_size) { size_t offs = le16_to_cpu(entry->e_value_offs); if (offs < min_offs) min_offs = offs; } + entry = next; } free = min_offs - ((void *)entry - (void *)IFIRST(header)) - sizeof(__u32); -- 2.39.2