CVE-2024-26785 Affecting kernel-syms package, versions <6.4.0-150600.23.17.1

Note: Versions mentioned in the description apply only to the upstream kernel-syms package and not the kernel-syms package as distributed by SLES. See How to fix? for SLES:15.6 relevant fixed versions and status.

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

iommufd: Fix protection fault in iommufd_test_syz_conv_iova

Syzkaller reported the following bug:

general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7] Call Trace: lock_acquire lock_acquire+0x1ce/0x4f0 down_read+0x93/0x4a0 iommufd_test_syz_conv_iova+0x56/0x1f0 iommufd_test_access_rw.isra.0+0x2ec/0x390 iommufd_test+0x1058/0x1e30 iommufd_fops_ioctl+0x381/0x510 vfs_ioctl __do_sys_ioctl __se_sys_ioctl __x64_sys_ioctl+0x170/0x1e0 do_syscall_x64 do_syscall_64+0x71/0x140

This is because the new iommufd_access_change_ioas() sets access->ioas to NULL during its process, so the lock might be gone in a concurrent racing context.

Fix this by doing the same access->ioas sanity as iommufd_access_rw() and iommufd_access_pin_pages() functions do.

• https://www.suse.com/security/cve/CVE-2024-26785.html
• https://bugzilla.suse.com/1222779
• https://git.kernel.org/stable/c/cf7c2789822db8b5efa34f5ebcf1621bc0008d48
• https://git.kernel.org/stable/c/fc719ecbca45c9c046640d72baddba3d83e0bc0b