CVE-2023-53835

In the Linux kernel, the following vulnerability has been resolved:

ext4: don't clear SB_RDONLY when remounting r/w until quota is re-enabled

When a file system currently mounted read/only is remounted read/write, if we clear the SB_RDONLY flag too early, before the quota is initialized, and there is another process/thread constantly attempting to create a directory, it's possible to trigger the

WARN_ON_ONCE(dquot_initialize_needed(inode));

in ext4xattrblock_set(), with the following stack trace:

WARNING: CPU: 0 PID: 5338 at fs/ext4/xattr.c:2141 ext4xattrblockset+0x2ef2/0x3680 RIP: 0010:ext4xattrblockset+0x2ef2/0x3680 fs/ext4/xattr.c:2141 Call Trace: ext4xattrsethandle+0xcd4/0x15c0 fs/ext4/xattr.c:2458 ext4initxattrs+0xa3/0x110 fs/ext4/xattrsecurity.c:44 securityinodeinitsecurity+0x2df/0x3f0 security/security.c:1147 __ext4newinode+0x347e/0x43d0 fs/ext4/ialloc.c:1324 ext4_mkdir+0x425/0xce0 fs/ext4/namei.c:2992 vfsmkdir+0x29d/0x450 fs/namei.c:4038 domkdirat+0x264/0x520 fs/namei.c:4061 __dosysmkdirat fs/namei.c:4076 [inline] __sesysmkdirat fs/namei.c:4074 [inline] __x64sysmkdirat+0x89/0xa0 fs/namei.c:4074