In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix information leak in btrfs_ioctl_logical_to_ino()
Syzbot reported the following information leak for in
btrfs_ioctl_logical_to_ino():
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x110 lib/usercopy.c:40
instrument_copy_to_user include/linux/instrumented.h:114 [inline]
_copy_to_user+0xbc/0x110 lib/usercopy.c:40
copy_to_user include/linux/uaccess.h:191 [inline]
btrfs_ioctl_logical_to_ino+0x440/0x750 fs/btrfs/ioctl.c:3499
btrfs_ioctl+0x714/0x1260
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:904 [inline]
__se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
__x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Uninit was created at:
__kmalloc_large_node+0x231/0x370 mm/slub.c:3921
__do_kmalloc_node mm/slub.c:3954 [inline]
__kmalloc_node+0xb07/0x1060 mm/slub.c:3973
kmalloc_node include/linux/slab.h:648 [inline]
kvmalloc_node+0xc0/0x2d0 mm/util.c:634
kvmalloc include/linux/slab.h:766 [inline]
init_data_container+0x49/0x1e0 fs/btrfs/backref.c:2779
btrfs_ioctl_logical_to_ino+0x17c/0x750 fs/btrfs/ioctl.c:3480
btrfs_ioctl+0x714/0x1260
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:904 [inline]
__se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
__x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Bytes 40-65535 of 65536 are uninitialized
Memory access of size 65536 starts at ffff888045a40000
This happens, because we're copying a 'struct btrfs_data_container' back
to user-space. This btrfs_data_container is allocated in
'init_data_container()' via kvmalloc(), which does not zero-fill the
memory.
Fix this by using kvzalloc() which zeroes out the memory on allocation.
Additional Descriptions (1)
En el kernel de Linux, se resolvió la siguiente vulnerabilidad: btrfs: corrige la fuga de información en btrfs_ioctl_logic_to_ino() Syzbot informó la siguiente fuga de información en btrfs_ioctl_logic_to_ino(): ERROR: KMSAN: kernel-infoleak en instrument_copy_to_user include/linux/instrumented.h: 114 [en línea] ERROR: KMSAN: kernel-infoleak en _copy_to_user+0xbc/0x110 lib/usercopy.c:40 instrument_copy_to_user include/linux/instrumented.h:114 [en línea] _copy_to_user+0xbc/0x110 lib/usercopy.c:40 copy_to_user include/linux/uaccess.h:191 [en línea] btrfs_ioctl_logic_to_ino+0x440/0x750 fs/btrfs/ioctl.c:3499 btrfs_ioctl+0x714/0x1260 vfs_ioctl fs/ioctl.c:51 [en línea] __do_sys_ioctl fs/ioctl.c :904 [en línea] __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890 __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890 x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h: 17 do_syscall_x64 arco/ x86/entry/common.c:52 [en línea] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit se creó en: __kmalloc_large_node+0x231/0x370 mm/slub.c:3921 __do_kmalloc_node mm/slub.c:3954 [en línea] __kmalloc_node+0xb07/0x1060 mm/slub.c:3973 kmalloc_node include/linux/slab.h:648 [en línea] kvmalloc_node+0xc0/0x2d0 mm/util.c:634 kvmalloc incluye /linux/slab.h:766 [en línea] init_data_container+0x49/0x1e0 fs/btrfs/backref.c:2779 btrfs_ioctl_logic_to_ino+0x17c/0x750 fs/btrfs/ioctl.c:3480 btrfs_ioctl+0x714/0x1260 ctl fs/ioctl.c :51 [en línea] __do_sys_ioctl fs/ioctl.c:904 [en línea] __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890 __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890 x64_sys_call+0x1883/0x Arco 3b50/x86/incluye /generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/common.c:52 [en línea] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 Entry_SYSCALL_64_after_hwframe+0x77/0x7f Bytes 40-65535 de 65536 no están inicializados El acceso a la memoria de tamaño 65536 comienza en ffff888045a40000. Esto sucede porque estamos copiando una 'estructura btrfs_data_container' nuevamente al espacio de usuario. Este btrfs_data_container se asigna en 'init_data_container()' a través de kvmalloc(), que no llena la memoria con ceros. Solucione este problema usando kvzalloc() que pone a cero la memoria al asignarla.