CVE-2025-68295smb: client: fix memory leak in cifs_construct_tcon()

Official description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix memory leak in cifs_construct_tcon() When having a multiuser mount with domain= specified and using cifscreds, cifs_set_cifscreds() will end up setting @ctx->domainname, so it needs to be freed before leaving cifs_construct_tcon(). This fixes the following memory leak reported by kmemleak: mount.cifs //srv/share /mnt -o domain=ZELDA,multiuser,... su - testuser cifscreds add -d ZELDA -u testuser ... ls /mnt/1 ... umount /mnt echo scan > /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak unreferenced object 0xffff8881203c3f08 (size 8): comm "ls", pid 5060, jiffies 4307222943 hex dump (first 8 bytes): 5a 45 4c 44 41 00 cc cc ZELDA... backtrace (crc d109a8cf): __kmalloc_node_track_caller_noprof+0x572/0x710 kstrdup+0x3a/0x70 cifs_sb_tlink+0x1209/0x1770 [cifs] cifs_get_fattr+0xe1/0xf50 [cifs] cifs_get_inode_info+0xb5/0x240 [cifs] cifs_revalidate_dentry_attr+0x2d1/0x470 [cifs] cifs_getattr+0x28e/0x450 [cifs] vfs_getattr_nosec+0x126/0x180 vfs_statx+0xf6/0x220 do_statx+0xab/0x110 __x64_sys_statx+0xd5/0x130 do_syscall_64+0xbb/0x380 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/ff8f9bd1c46ee02d5558293915d42e82646d5ee9
• https://git.kernel.org/stable/c/d146e96fef876492979658dce644305de35878d4
• https://git.kernel.org/stable/c/3dd546e867e94c2f954bca45a961b6104ba708b6
• https://git.kernel.org/stable/c/f62ffdfb431bdfa4b6d24233b7fd830eca0b801e
• https://git.kernel.org/stable/c/f15288c137d960836277d0e3ecc62de68e52f00f
• https://git.kernel.org/stable/c/a67e91d5f446e455dd9201cdd6e865f7078d251d
• https://git.kernel.org/stable/c/3184b6a5a24ec9ee74087b2a550476f386df7dc2