In the Linux kernel, the following vulnerability has been resolved: bus: mhi: core: Validate channel ID when processing command completions MHI reads the channel ID from the event ring element sent by the device which can be any value between 0 and 255. In order to prevent any out of bound accesses, add a check against the maximum number of channels supported by the controller and those channels not configured yet so as to skip processing of that event ring element.

A flaw was found in the Linux kernel's ext4 filesystem. A local user can cause an out-of-bounds write and a denial of service or unspecified other impact is possible by mounting and operating a crafted ext4 filesystem image.

The sr_do_ioctl function in drivers/scsi/sr_ioctl.c in the Linux kernel through 4.16.12 allows local users to cause a denial of service (stack-based buffer overflow) or possibly have unspecified other impact because sense buffers have different sizes at the CDROM layer and the SCSI layer, as demonstrated by a CDROMREADMODE2 ioctl call.

drivers/char/virtio_console.c in the Linux kernel 4.9.x and 4.10.x before 4.10.12 interacts incorrectly with the CONFIG_VMAP_STACK option, which allows local users to cause a denial of service (system crash or memory corruption) or possibly have unspecified other impact by leveraging use of more than one virtual page for a DMA scatterlist.

The vmw_surface_define_ioctl function in drivers/gpu/drm/vmwgfx/vmwgfx_surface.c in the Linux kernel through 4.10.6 does not validate addition of certain levels data, which allows local users to trigger an integer overflow and out-of-bounds write, and cause a denial of service (system hang or crash) or possibly gain privileges, via a crafted ioctl call for a /dev/dri/renderD* device.

The packet_set_ring function in net/packet/af_packet.c in the Linux kernel through 4.10.6 does not properly validate certain block-size data, which allows local users to cause a denial of service (integer signedness error and out-of-bounds write), or gain privileges (if the CAP_NET_RAW capability is held), via crafted system calls.

In kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds write when many elements are placed in a single bucket. NOTE: exploitation might be impractical without the CAP_SYS_ADMIN capability.

The eBPF ALU32 bounds tracking for bitwise ops (AND, OR and XOR) in the Linux kernel did not properly update 32-bit bounds, which could be turned into out of bounds reads and writes in the Linux kernel and therefore, arbitrary code execution. This issue was fixed via commit 049c4e13714e ("bpf: Fix alu32 const subreg bound tracking on bitwise operations") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. The AND/OR issues were introduced by commit 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking") (5.7-rc1) and the XOR variant was introduced by 2921c90d4718 ("bpf:Fix a verifier failure with xor") ( 5.10-rc1).

The HMAC implementation (crypto/hmac.c) in the Linux kernel before 4.14.8 does not validate that the underlying cryptographic hash algorithm is unkeyed, allowing a local attacker able to use the AF_ALG-based hash interface (CONFIG_CRYPTO_USER_API_HASH) and the SHA-3 hash algorithm (CONFIG_CRYPTO_SHA3) to cause a kernel stack buffer overflow by executing a crafted sequence of system calls that encounter a missing SHA-3 initialization.

In the Linux kernel, the following vulnerability has been resolved: jffs2: Prevent rtime decompress memory corruption The rtime decompression routine does not fully check bounds during the entirety of the decompression pass and can corrupt memory outside the decompression buffer if the compressed data is corrupted. This adds the required check to prevent this failure mode.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Adding array index check to prevent memory corruption [Why & How] Array indices out of bound caused memory corruption. Adding checks to ensure that array index stays in bound.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix Out-of-Bounds Write in ksmbd_vfs_stream_write An offset from client could be a negative value, It could allows to write data outside the bounds of the allocated buffer. Note that this issue is coming when setting 'vfs objects = streams_xattr parameter' in ksmbd.conf.

In the Linux kernel, the following vulnerability has been resolved: media: uvcvideo: Skip parsing frames of type UVC_VS_UNDEFINED in uvc_parse_format This can lead to out of bounds writes since frames of this type were not taken into account when calculating the size of the frames buffer in uvc_parse_streaming.

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix potential out-of-bound accesses for Extigy and Mbox devices A bogus device can provide a bNumConfigurations value that exceeds the initial value used in usb_get_configuration for allocating dev->config. This can lead to out-of-bounds accesses later, e.g. in usb_destroy_configuration.

In the Linux kernel, the following vulnerability has been resolved: drm/xe/ufence: Prefetch ufence addr to catch bogus address access_ok() only checks for addr overflow so also try to read the addr to catch invalid addr sent from userspace. (cherry picked from commit 9408c4508483ffc60811e910a93d6425b8e63928)

In the Linux kernel, the following vulnerability has been resolved: initramfs: avoid filename buffer overrun The initramfs filename field is defined in Documentation/driver-api/early-userspace/buffer-format.rst as: 37 cpio_file := ALGN(4) + cpio_header + filename + "\0" + ALGN(4) + data ... 55 ============= ================== ========================= 56 Field name Field size Meaning 57 ============= ================== ========================= ... 70 c_namesize 8 bytes Length of filename, including final \0 When extracting an initramfs cpio archive, the kernel's do_name() path handler assumes a zero-terminated path at @collected, passing it directly to filp_open() / init_mkdir() / init_mknod(). If a specially crafted cpio entry carries a non-zero-terminated filename and is followed by uninitialized memory, then a file may be created with trailing characters that represent the uninitialized memory. The ability to create an initramfs entry would imply already having full control of the system, so the buffer overrun shouldn't be considered a security vulnerability. Append the output of the following bash script to an existing initramfs and observe any created /initramfs_test_fname_overrunAA* path. E.g. ./reproducer.sh | gzip >> /myinitramfs It's easiest to observe non-zero uninitialized memory when the output is gzipped, as it'll overflow the heap allocated @out_buf in __gunzip(), rather than the initrd_start+initrd_size block. ---- reproducer.sh ---- nilchar="A" # change to "\0" to properly zero terminate / pad magic="070701" ino=1 mode=$(( 0100777 )) uid=0 gid=0 nlink=1 mtime=1 filesize=0 devmajor=0 devminor=1 rdevmajor=0 rdevminor=0 csum=0 fname="initramfs_test_fname_overrun" namelen=$(( ${#fname} + 1 )) # plus one to account for terminator printf "%s%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%s" \ $magic $ino $mode $uid $gid $nlink $mtime $filesize \ $devmajor $devminor $rdevmajor $rdevminor $namelen $csum $fname termpadlen=$(( 1 + ((4 - ((110 + $namelen) & 3)) % 4) )) printf "%.s${nilchar}" $(seq 1 $termpadlen) ---- reproducer.sh ---- Symlink filename fields handled in do_symlink() won't overrun past the data segment, due to the explicit zero-termination of the symlink target. Fix filename buffer overrun by aborting the initramfs FSM if any cpio entry doesn't carry a zero-terminator at the expected (name_len - 1) offset.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix OOBs when building SMB2_IOCTL request When using encryption, either enforced by the server or when using 'seal' mount option, the client will squash all compound request buffers down for encryption into a single iov in smb2_set_next_command(). SMB2_ioctl_init() allocates a small buffer (448 bytes) to hold the SMB2_IOCTL request in the first iov, and if the user passes an input buffer that is greater than 328 bytes, smb2_set_next_command() will end up writing off the end of @rqst->iov[0].iov_base as shown below: mount.cifs //srv/share /mnt -o ...,seal ln -s $(perl -e "print('a')for 1..1024") /mnt/link BUG: KASAN: slab-out-of-bounds in smb2_set_next_command.cold+0x1d6/0x24c [cifs] Write of size 4116 at addr ffff8881148fcab8 by task ln/859 CPU: 1 UID: 0 PID: 859 Comm: ln Not tainted 6.12.0-rc3 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 ? smb2_set_next_command.cold+0x1d6/0x24c [cifs] print_report+0x156/0x4d9 ? smb2_set_next_command.cold+0x1d6/0x24c [cifs] ? __virt_addr_valid+0x145/0x310 ? __phys_addr+0x46/0x90 ? smb2_set_next_command.cold+0x1d6/0x24c [cifs] kasan_report+0xda/0x110 ? smb2_set_next_command.cold+0x1d6/0x24c [cifs] kasan_check_range+0x10f/0x1f0 __asan_memcpy+0x3c/0x60 smb2_set_next_command.cold+0x1d6/0x24c [cifs] smb2_compound_op+0x238c/0x3840 [cifs] ? kasan_save_track+0x14/0x30 ? kasan_save_free_info+0x3b/0x70 ? vfs_symlink+0x1a1/0x2c0 ? do_symlinkat+0x108/0x1c0 ? __pfx_smb2_compound_op+0x10/0x10 [cifs] ? kmem_cache_free+0x118/0x3e0 ? cifs_get_writable_path+0xeb/0x1a0 [cifs] smb2_get_reparse_inode+0x423/0x540 [cifs] ? __pfx_smb2_get_reparse_inode+0x10/0x10 [cifs] ? rcu_is_watching+0x20/0x50 ? __kmalloc_noprof+0x37c/0x480 ? smb2_create_reparse_symlink+0x257/0x490 [cifs] ? smb2_create_reparse_symlink+0x38f/0x490 [cifs] smb2_create_reparse_symlink+0x38f/0x490 [cifs] ? __pfx_smb2_create_reparse_symlink+0x10/0x10 [cifs] ? find_held_lock+0x8a/0xa0 ? hlock_class+0x32/0xb0 ? __build_path_from_dentry_optional_prefix+0x19d/0x2e0 [cifs] cifs_symlink+0x24f/0x960 [cifs] ? __pfx_make_vfsuid+0x10/0x10 ? __pfx_cifs_symlink+0x10/0x10 [cifs] ? make_vfsgid+0x6b/0xc0 ? generic_permission+0x96/0x2d0 vfs_symlink+0x1a1/0x2c0 do_symlinkat+0x108/0x1c0 ? __pfx_do_symlinkat+0x10/0x10 ? strncpy_from_user+0xaa/0x160 __x64_sys_symlinkat+0xb9/0xf0 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f08d75c13bb

In the Linux kernel, the following vulnerability has been resolved: fbdev: sisfb: Fix strbuf array overflow The values of the variables xres and yres are placed in strbuf. These variables are obtained from strbuf1. The strbuf1 array contains digit characters and a space if the array contains non-digit characters. Then, when executing sprintf(strbuf, "%ux%ux8", xres, yres); more than 16 bytes will be written to strbuf. It is suggested to increase the size of the strbuf array to 24. Found by Linux Verification Center (linuxtesting.org) with SVACE.

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix kernel bug due to missing clearing of checked flag Syzbot reported that in directory operations after nilfs2 detects filesystem corruption and degrades to read-only, __block_write_begin_int(), which is called to prepare block writes, may fail the BUG_ON check for accesses exceeding the folio/page size, triggering a kernel bug. This was found to be because the "checked" flag of a page/folio was not cleared when it was discarded by nilfs2's own routine, which causes the sanity check of directory entries to be skipped when the directory page/folio is reloaded. So, fix that. This was necessary when the use of nilfs2's own page discard routine was applied to more than just metadata files.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/pm: Vangogh: Fix kernel memory out of bounds write KASAN reports that the GPU metrics table allocated in vangogh_tables_init() is not large enough for the memset done in smu_cmn_init_soft_gpu_metrics(). Condensed report follows: [ 33.861314] BUG: KASAN: slab-out-of-bounds in smu_cmn_init_soft_gpu_metrics+0x73/0x200 [amdgpu] [ 33.861799] Write of size 168 at addr ffff888129f59500 by task mangoapp/1067 ... [ 33.861808] CPU: 6 UID: 1000 PID: 1067 Comm: mangoapp Tainted: G W 6.12.0-rc4 #356 1a56f59a8b5182eeaf67eb7cb8b13594dd23b544 [ 33.861816] Tainted: [W]=WARN [ 33.861818] Hardware name: Valve Galileo/Galileo, BIOS F7G0107 12/01/2023 [ 33.861822] Call Trace: [ 33.861826] <TASK> [ 33.861829] dump_stack_lvl+0x66/0x90 [ 33.861838] print_report+0xce/0x620 [ 33.861853] kasan_report+0xda/0x110 [ 33.862794] kasan_check_range+0xfd/0x1a0 [ 33.862799] __asan_memset+0x23/0x40 [ 33.862803] smu_cmn_init_soft_gpu_metrics+0x73/0x200 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779] [ 33.863306] vangogh_get_gpu_metrics_v2_4+0x123/0xad0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779] [ 33.864257] vangogh_common_get_gpu_metrics+0xb0c/0xbc0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779] [ 33.865682] amdgpu_dpm_get_gpu_metrics+0xcc/0x110 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779] [ 33.866160] amdgpu_get_gpu_metrics+0x154/0x2d0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779] [ 33.867135] dev_attr_show+0x43/0xc0 [ 33.867147] sysfs_kf_seq_show+0x1f1/0x3b0 [ 33.867155] seq_read_iter+0x3f8/0x1140 [ 33.867173] vfs_read+0x76c/0xc50 [ 33.867198] ksys_read+0xfb/0x1d0 [ 33.867214] do_syscall_64+0x90/0x160 ... [ 33.867353] Allocated by task 378 on cpu 7 at 22.794876s: [ 33.867358] kasan_save_stack+0x33/0x50 [ 33.867364] kasan_save_track+0x17/0x60 [ 33.867367] __kasan_kmalloc+0x87/0x90 [ 33.867371] vangogh_init_smc_tables+0x3f9/0x840 [amdgpu] [ 33.867835] smu_sw_init+0xa32/0x1850 [amdgpu] [ 33.868299] amdgpu_device_init+0x467b/0x8d90 [amdgpu] [ 33.868733] amdgpu_driver_load_kms+0x19/0xf0 [amdgpu] [ 33.869167] amdgpu_pci_probe+0x2d6/0xcd0 [amdgpu] [ 33.869608] local_pci_probe+0xda/0x180 [ 33.869614] pci_device_probe+0x43f/0x6b0 Empirically we can confirm that the former allocates 152 bytes for the table, while the latter memsets the 168 large block. Root cause appears that when GPU metrics tables for v2_4 parts were added it was not considered to enlarge the table to fit. The fix in this patch is rather "brute force" and perhaps later should be done in a smarter way, by extracting and consolidating the part version to size logic to a common helper, instead of brute forcing the largest possible allocation. Nevertheless, for now this works and fixes the out of bounds write. v2: * Drop impossible v3_0 case. (Mario) (cherry picked from commit 0880f58f9609f0200483a49429af0f050d281703)

In the Linux kernel, the following vulnerability has been resolved: spi: nxp-fspi: fix the KASAN report out-of-bounds bug Change the memcpy length to fix the out-of-bounds issue when writing the data that is not 4 byte aligned to TX FIFO. To reproduce the issue, write 3 bytes data to NOR chip. dd if=3b of=/dev/mtd0 [ 36.926103] ================================================================== [ 36.933409] BUG: KASAN: slab-out-of-bounds in nxp_fspi_exec_op+0x26ec/0x2838 [ 36.940514] Read of size 4 at addr ffff00081037c2a0 by task dd/455 [ 36.946721] [ 36.948235] CPU: 3 UID: 0 PID: 455 Comm: dd Not tainted 6.11.0-rc5-gc7b0e37c8434 #1070 [ 36.956185] Hardware name: Freescale i.MX8QM MEK (DT) [ 36.961260] Call trace: [ 36.963723] dump_backtrace+0x90/0xe8 [ 36.967414] show_stack+0x18/0x24 [ 36.970749] dump_stack_lvl+0x78/0x90 [ 36.974451] print_report+0x114/0x5cc [ 36.978151] kasan_report+0xa4/0xf0 [ 36.981670] __asan_report_load_n_noabort+0x1c/0x28 [ 36.986587] nxp_fspi_exec_op+0x26ec/0x2838 [ 36.990800] spi_mem_exec_op+0x8ec/0xd30 [ 36.994762] spi_mem_no_dirmap_read+0x190/0x1e0 [ 36.999323] spi_mem_dirmap_write+0x238/0x32c [ 37.003710] spi_nor_write_data+0x220/0x374 [ 37.007932] spi_nor_write+0x110/0x2e8 [ 37.011711] mtd_write_oob_std+0x154/0x1f0 [ 37.015838] mtd_write_oob+0x104/0x1d0 [ 37.019617] mtd_write+0xb8/0x12c [ 37.022953] mtdchar_write+0x224/0x47c [ 37.026732] vfs_write+0x1e4/0x8c8 [ 37.030163] ksys_write+0xec/0x1d0 [ 37.033586] __arm64_sys_write+0x6c/0x9c [ 37.037539] invoke_syscall+0x6c/0x258 [ 37.041327] el0_svc_common.constprop.0+0x160/0x22c [ 37.046244] do_el0_svc+0x44/0x5c [ 37.049589] el0_svc+0x38/0x78 [ 37.052681] el0t_64_sync_handler+0x13c/0x158 [ 37.057077] el0t_64_sync+0x190/0x194 [ 37.060775] [ 37.062274] Allocated by task 455: [ 37.065701] kasan_save_stack+0x2c/0x54 [ 37.069570] kasan_save_track+0x20/0x3c [ 37.073438] kasan_save_alloc_info+0x40/0x54 [ 37.077736] __kasan_kmalloc+0xa0/0xb8 [ 37.081515] __kmalloc_noprof+0x158/0x2f8 [ 37.085563] mtd_kmalloc_up_to+0x120/0x154 [ 37.089690] mtdchar_write+0x130/0x47c [ 37.093469] vfs_write+0x1e4/0x8c8 [ 37.096901] ksys_write+0xec/0x1d0 [ 37.100332] __arm64_sys_write+0x6c/0x9c [ 37.104287] invoke_syscall+0x6c/0x258 [ 37.108064] el0_svc_common.constprop.0+0x160/0x22c [ 37.112972] do_el0_svc+0x44/0x5c [ 37.116319] el0_svc+0x38/0x78 [ 37.119401] el0t_64_sync_handler+0x13c/0x158 [ 37.123788] el0t_64_sync+0x190/0x194 [ 37.127474] [ 37.128977] The buggy address belongs to the object at ffff00081037c2a0 [ 37.128977] which belongs to the cache kmalloc-8 of size 8 [ 37.141177] The buggy address is located 0 bytes inside of [ 37.141177] allocated 3-byte region [ffff00081037c2a0, ffff00081037c2a3) [ 37.153465] [ 37.154971] The buggy address belongs to the physical page: [ 37.160559] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x89037c [ 37.168596] flags: 0xbfffe0000000000(node=0|zone=2|lastcpupid=0x1ffff) [ 37.175149] page_type: 0xfdffffff(slab) [ 37.179021] raw: 0bfffe0000000000 ffff000800002500 dead000000000122 0000000000000000 [ 37.186788] raw: 0000000000000000 0000000080800080 00000001fdffffff 0000000000000000 [ 37.194553] page dumped because: kasan: bad access detected [ 37.200144] [ 37.201647] Memory state around the buggy address: [ 37.206460] ffff00081037c180: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc [ 37.213701] ffff00081037c200: fa fc fc fc 05 fc fc fc 03 fc fc fc 02 fc fc fc [ 37.220946] >ffff00081037c280: 06 fc fc fc 03 fc fc fc fc fc fc fc fc fc fc fc [ 37.228186] ^ [ 37.232473] ffff00081037c300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 37.239718] ffff00081037c380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 37.246962] ============================================================== ---truncated---

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix out-of-bounds write in trie_get_next_key() trie_get_next_key() allocates a node stack with size trie->max_prefixlen, while it writes (trie->max_prefixlen + 1) nodes to the stack when it has full paths from the root to leaves. For example, consider a trie with max_prefixlen is 8, and the nodes with key 0x00/0, 0x00/1, 0x00/2, ... 0x00/8 inserted. Subsequent calls to trie_get_next_key with _key with .prefixlen = 8 make 9 nodes be written on the node stack with size 8.

In the Linux kernel, the following vulnerability has been resolved: drm/v3d: Prevent out of bounds access in performance query extensions Check that the number of perfmons userspace is passing in the copy and reset extensions is not greater than the internal kernel storage where the ids will be copied into.

In the Linux kernel, the following vulnerability has been resolved: arm64: entry: avoid kprobe recursion The cortex_a76_erratum_1463225_debug_handler() function is called when handling debug exceptions (and synchronous exceptions from BRK instructions), and so is called when a probed function executes. If the compiler does not inline cortex_a76_erratum_1463225_debug_handler(), it can be probed. If cortex_a76_erratum_1463225_debug_handler() is probed, any debug exception or software breakpoint exception will result in recursive exceptions leading to a stack overflow. This can be triggered with the ftrace multiple_probes selftest, and as per the example splat below. This is a regression caused by commit: 6459b8469753e9fe ("arm64: entry: consolidate Cortex-A76 erratum 1463225 workaround") ... which removed the NOKPROBE_SYMBOL() annotation associated with the function. My intent was that cortex_a76_erratum_1463225_debug_handler() would be inlined into its caller, el1_dbg(), which is marked noinstr and cannot be probed. Mark cortex_a76_erratum_1463225_debug_handler() as __always_inline to ensure this. Example splat prior to this patch (with recursive entries elided): | # echo p cortex_a76_erratum_1463225_debug_handler > /sys/kernel/debug/tracing/kprobe_events | # echo p do_el0_svc >> /sys/kernel/debug/tracing/kprobe_events | # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable | Insufficient stack space to handle exception! | ESR: 0x0000000096000047 -- DABT (current EL) | FAR: 0xffff800009cefff0 | Task stack: [0xffff800009cf0000..0xffff800009cf4000] | IRQ stack: [0xffff800008000000..0xffff800008004000] | Overflow stack: [0xffff00007fbc00f0..0xffff00007fbc10f0] | CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2 | Hardware name: linux,dummy-virt (DT) | pstate: 604003c5 (nZCv DAIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : arm64_enter_el1_dbg+0x4/0x20 | lr : el1_dbg+0x24/0x5c | sp : ffff800009cf0000 | x29: ffff800009cf0000 x28: ffff000002c74740 x27: 0000000000000000 | x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 | x23: 00000000604003c5 x22: ffff80000801745c x21: 0000aaaac95ac068 | x20: 00000000f2000004 x19: ffff800009cf0040 x18: 0000000000000000 | x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 | x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 | x11: 0000000000000010 x10: ffff800008c87190 x9 : ffff800008ca00d0 | x8 : 000000000000003c x7 : 0000000000000000 x6 : 0000000000000000 | x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000000043a4 | x2 : 00000000f2000004 x1 : 00000000f2000004 x0 : ffff800009cf0040 | Kernel panic - not syncing: kernel stack overflow | CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2 | Hardware name: linux,dummy-virt (DT) | Call trace: | dump_backtrace+0xe4/0x104 | show_stack+0x18/0x4c | dump_stack_lvl+0x64/0x7c | dump_stack+0x18/0x38 | panic+0x14c/0x338 | test_taint+0x0/0x2c | panic_bad_stack+0x104/0x118 | handle_bad_stack+0x34/0x48 | __bad_stack+0x78/0x7c | arm64_enter_el1_dbg+0x4/0x20 | el1h_64_sync_handler+0x40/0x98 | el1h_64_sync+0x64/0x68 | cortex_a76_erratum_1463225_debug_handler+0x0/0x34 ... | el1h_64_sync_handler+0x40/0x98 | el1h_64_sync+0x64/0x68 | cortex_a76_erratum_1463225_debug_handler+0x0/0x34 ... | el1h_64_sync_handler+0x40/0x98 | el1h_64_sync+0x64/0x68 | cortex_a76_erratum_1463225_debug_handler+0x0/0x34 | el1h_64_sync_handler+0x40/0x98 | el1h_64_sync+0x64/0x68 | do_el0_svc+0x0/0x28 | el0t_64_sync_handler+0x84/0xf0 | el0t_64_sync+0x18c/0x190 | Kernel Offset: disabled | CPU features: 0x0080,00005021,19001080 | Memory Limit: none | ---[ end Kernel panic - not syncing: kernel stack overflow ]--- With this patch, cortex_a76_erratum_1463225_debug_handler() is inlined into el1_dbg(), and el1_dbg() cannot be probed: | # echo p cortex_a76_erratum_1463225_debug_handler > /sys/kernel/debug/tracing/kprobe_events | sh: write error: No such file or directory | # grep -w cortex_a76_errat ---truncated---

In the Linux kernel, the following vulnerability has been resolved: net: pse-pd: Fix out of bound for loop Adjust the loop limit to prevent out-of-bounds access when iterating over PI structures. The loop should not reach the index pcdev->nr_lines since we allocate exactly pcdev->nr_lines number of PI structures. This fix ensures proper bounds are maintained during iterations.

In the Linux kernel, the following vulnerability has been resolved: drivers: media: dvb-frontends/rtl2830: fix an out-of-bounds write error Ensure index in rtl2830_pid_filter does not exceed 31 to prevent out-of-bounds access. dev->filters is a 32-bit value, so set_bit and clear_bit functions should only operate on indices from 0 to 31. If index is 32, it will attempt to access a non-existent 33rd bit, leading to out-of-bounds access. Change the boundary check from index > 32 to index >= 32 to resolve this issue.

In the Linux kernel, the following vulnerability has been resolved: ice: move netif_queue_set_napi to rtnl-protected sections Currently, netif_queue_set_napi() is called from ice_vsi_rebuild() that is not rtnl-locked when called from the reset. This creates the need to take the rtnl_lock just for a single function and complicates the synchronization with .ndo_bpf. At the same time, there no actual need to fill napi-to-queue information at this exact point. Fill napi-to-queue information when opening the VSI and clear it when the VSI is being closed. Those routines are already rtnl-locked. Also, rewrite napi-to-queue assignment in a way that prevents inclusion of XDP queues, as this leads to out-of-bounds writes, such as one below. [ +0.000004] BUG: KASAN: slab-out-of-bounds in netif_queue_set_napi+0x1c2/0x1e0 [ +0.000012] Write of size 8 at addr ffff889881727c80 by task bash/7047 [ +0.000006] CPU: 24 PID: 7047 Comm: bash Not tainted 6.10.0-rc2+ #2 [ +0.000004] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0014.082620210524 08/26/2021 [ +0.000003] Call Trace: [ +0.000003] <TASK> [ +0.000002] dump_stack_lvl+0x60/0x80 [ +0.000007] print_report+0xce/0x630 [ +0.000007] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ +0.000007] ? __virt_addr_valid+0x1c9/0x2c0 [ +0.000005] ? netif_queue_set_napi+0x1c2/0x1e0 [ +0.000003] kasan_report+0xe9/0x120 [ +0.000004] ? netif_queue_set_napi+0x1c2/0x1e0 [ +0.000004] netif_queue_set_napi+0x1c2/0x1e0 [ +0.000005] ice_vsi_close+0x161/0x670 [ice] [ +0.000114] ice_dis_vsi+0x22f/0x270 [ice] [ +0.000095] ice_pf_dis_all_vsi.constprop.0+0xae/0x1c0 [ice] [ +0.000086] ice_prepare_for_reset+0x299/0x750 [ice] [ +0.000087] pci_dev_save_and_disable+0x82/0xd0 [ +0.000006] pci_reset_function+0x12d/0x230 [ +0.000004] reset_store+0xa0/0x100 [ +0.000006] ? __pfx_reset_store+0x10/0x10 [ +0.000002] ? __pfx_mutex_lock+0x10/0x10 [ +0.000004] ? __check_object_size+0x4c1/0x640 [ +0.000007] kernfs_fop_write_iter+0x30b/0x4a0 [ +0.000006] vfs_write+0x5d6/0xdf0 [ +0.000005] ? fd_install+0x180/0x350 [ +0.000005] ? __pfx_vfs_write+0x10/0xA10 [ +0.000004] ? do_fcntl+0x52c/0xcd0 [ +0.000004] ? kasan_save_track+0x13/0x60 [ +0.000003] ? kasan_save_free_info+0x37/0x60 [ +0.000006] ksys_write+0xfa/0x1d0 [ +0.000003] ? __pfx_ksys_write+0x10/0x10 [ +0.000002] ? __x64_sys_fcntl+0x121/0x180 [ +0.000004] ? _raw_spin_lock+0x87/0xe0 [ +0.000005] do_syscall_64+0x80/0x170 [ +0.000007] ? _raw_spin_lock+0x87/0xe0 [ +0.000004] ? __pfx__raw_spin_lock+0x10/0x10 [ +0.000003] ? file_close_fd_locked+0x167/0x230 [ +0.000005] ? syscall_exit_to_user_mode+0x7d/0x220 [ +0.000005] ? do_syscall_64+0x8c/0x170 [ +0.000004] ? do_syscall_64+0x8c/0x170 [ +0.000003] ? do_syscall_64+0x8c/0x170 [ +0.000003] ? fput+0x1a/0x2c0 [ +0.000004] ? filp_close+0x19/0x30 [ +0.000004] ? do_dup2+0x25a/0x4c0 [ +0.000004] ? __x64_sys_dup2+0x6e/0x2e0 [ +0.000002] ? syscall_exit_to_user_mode+0x7d/0x220 [ +0.000004] ? do_syscall_64+0x8c/0x170 [ +0.000003] ? __count_memcg_events+0x113/0x380 [ +0.000005] ? handle_mm_fault+0x136/0x820 [ +0.000005] ? do_user_addr_fault+0x444/0xa80 [ +0.000004] ? clear_bhb_loop+0x25/0x80 [ +0.000004] ? clear_bhb_loop+0x25/0x80 [ +0.000002] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ +0.000005] RIP: 0033:0x7f2033593154

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Validate TA binary size Add TA binary size validation to avoid OOB write. (cherry picked from commit c0a04e3570d72aaf090962156ad085e37c62e442)

Linux drivers/char/lp.c Out-of-Bounds Write. Due to a missing bounds check, and the fact that parport_ptr integer is static, a 'secure boot' kernel command line adversary (can happen due to bootloader vulns, e.g. Google Nexus 6's CVE-2016-10277, where due to a vulnerability the adversary has partial control over the command line) can overflow the parport_nr array in the following code, by appending many (>LP_NO) 'lp=none' arguments to the command line.

In the Linux kernel, the following vulnerability has been resolved: afs: Increase buffer size in afs_update_volume_status() The max length of volume->vid value is 20 characters. So increase idbuf[] size up to 24 to avoid overflow. Found by Linux Verification Center (linuxtesting.org) with SVACE. [DH: Actually, it's 20 + NUL, so increase it to 24 and use snprintf()]

In the Linux kernel, the following vulnerability has been resolved: kdb: Fix buffer overflow during tab-complete Currently, when the user attempts symbol completion with the Tab key, kdb will use strncpy() to insert the completed symbol into the command buffer. Unfortunately it passes the size of the source buffer rather than the destination to strncpy() with predictably horrible results. Most obviously if the command buffer is already full but cp, the cursor position, is in the middle of the buffer, then we will write past the end of the supplied buffer. Fix this by replacing the dubious strncpy() calls with memmove()/memcpy() calls plus explicit boundary checks to make sure we have enough space before we start moving characters around.

In the Linux kernel, the following vulnerability has been resolved: tipc: Return non-zero value from tipc_udp_addr2str() on error tipc_udp_addr2str() should return non-zero value if the UDP media address is invalid. Otherwise, a buffer overflow access can occur in tipc_media_addr_printf(). Fix this by returning 1 on an invalid UDP media address.

kernel/ucount.c in the Linux kernel 5.14 through 5.16.4, when unprivileged user namespaces are enabled, allows a use-after-free and privilege escalation because a ucounts object can outlive its namespace.

In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: fix use-after-free due to race with dev replace While loading a zone's info during creation of a block group, we can race with a device replace operation and then trigger a use-after-free on the device that was just replaced (source device of the replace operation). This happens because at btrfs_load_zone_info() we extract a device from the chunk map into a local variable and then use the device while not under the protection of the device replace rwsem. So if there's a device replace operation happening when we extract the device and that device is the source of the replace operation, we will trigger a use-after-free if before we finish using the device the replace operation finishes and frees the device. Fix this by enlarging the critical section under the protection of the device replace rwsem so that all uses of the device are done inside the critical section.

In the Linux kernel, the following vulnerability has been resolved: greybus: Fix use-after-free bug in gb_interface_release due to race condition. In gb_interface_create, &intf->mode_switch_completion is bound with gb_interface_mode_switch_work. Then it will be started by gb_interface_request_mode_switch. Here is the relevant code. if (!queue_work(system_long_wq, &intf->mode_switch_work)) { ... } If we call gb_interface_release to make cleanup, there may be an unfinished work. This function will call kfree to free the object "intf". However, if gb_interface_mode_switch_work is scheduled to run after kfree, it may cause use-after-free error as gb_interface_mode_switch_work will use the object "intf". The possible execution flow that may lead to the issue is as follows: CPU0 CPU1 | gb_interface_create | gb_interface_request_mode_switch gb_interface_release | kfree(intf) (free) | | gb_interface_mode_switch_work | mutex_lock(&intf->mutex) (use) Fix it by canceling the work before kfree.

In the Linux kernel, the following vulnerability has been resolved: drm/i915/hwmon: Get rid of devm When both hwmon and hwmon drvdata (on which hwmon depends) are device managed resources, the expectation, on device unbind, is that hwmon will be released before drvdata. However, in i915 there are two separate code paths, which both release either drvdata or hwmon and either can be released before the other. These code paths (for device unbind) are as follows (see also the bug referenced below): Call Trace: release_nodes+0x11/0x70 devres_release_group+0xb2/0x110 component_unbind_all+0x8d/0xa0 component_del+0xa5/0x140 intel_pxp_tee_component_fini+0x29/0x40 [i915] intel_pxp_fini+0x33/0x80 [i915] i915_driver_remove+0x4c/0x120 [i915] i915_pci_remove+0x19/0x30 [i915] pci_device_remove+0x32/0xa0 device_release_driver_internal+0x19c/0x200 unbind_store+0x9c/0xb0 and Call Trace: release_nodes+0x11/0x70 devres_release_all+0x8a/0xc0 device_unbind_cleanup+0x9/0x70 device_release_driver_internal+0x1c1/0x200 unbind_store+0x9c/0xb0 This means that in i915, if use devm, we cannot gurantee that hwmon will always be released before drvdata. Which means that we have a uaf if hwmon sysfs is accessed when drvdata has been released but hwmon hasn't. The only way out of this seems to be do get rid of devm_ and release/free everything explicitly during device unbind. v2: Change commit message and other minor code changes v3: Cleanup from i915_hwmon_register on error (Armin Wolf) v4: Eliminate potential static analyzer warning (Rodrigo) Eliminate fetch_and_zero (Jani) v5: Restore previous logic for ddat_gt->hwmon_dev error return (Andi)

In the Linux kernel, the following vulnerability has been resolved: cachefiles: fix slab-use-after-free in cachefiles_ondemand_daemon_read() We got the following issue in a fuzz test of randomly issuing the restore command: ================================================================== BUG: KASAN: slab-use-after-free in cachefiles_ondemand_daemon_read+0xb41/0xb60 Read of size 8 at addr ffff888122e84088 by task ondemand-04-dae/963 CPU: 13 PID: 963 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #564 Call Trace: kasan_report+0x93/0xc0 cachefiles_ondemand_daemon_read+0xb41/0xb60 vfs_read+0x169/0xb50 ksys_read+0xf5/0x1e0 Allocated by task 116: kmem_cache_alloc+0x140/0x3a0 cachefiles_lookup_cookie+0x140/0xcd0 fscache_cookie_state_machine+0x43c/0x1230 [...] Freed by task 792: kmem_cache_free+0xfe/0x390 cachefiles_put_object+0x241/0x480 fscache_cookie_state_machine+0x5c8/0x1230 [...] ================================================================== Following is the process that triggers the issue: mount | daemon_thread1 | daemon_thread2 ------------------------------------------------------------ cachefiles_withdraw_cookie cachefiles_ondemand_clean_object(object) cachefiles_ondemand_send_req REQ_A = kzalloc(sizeof(*req) + data_len) wait_for_completion(&REQ_A->done) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req msg->object_id = req->object->ondemand->ondemand_id ------ restore ------ cachefiles_ondemand_restore xas_for_each(&xas, req, ULONG_MAX) xas_set_mark(&xas, CACHEFILES_REQ_NEW) cachefiles_daemon_read cachefiles_ondemand_daemon_read REQ_A = cachefiles_ondemand_select_req copy_to_user(_buffer, msg, n) xa_erase(&cache->reqs, id) complete(&REQ_A->done) ------ close(fd) ------ cachefiles_ondemand_fd_release cachefiles_put_object cachefiles_put_object kmem_cache_free(cachefiles_object_jar, object) REQ_A->object->ondemand->ondemand_id // object UAF !!! When we see the request within xa_lock, req->object must not have been freed yet, so grab the reference count of object before xa_unlock to avoid the above issue.

In the Linux kernel, the following vulnerability has been resolved: dma-mapping: benchmark: handle NUMA_NO_NODE correctly cpumask_of_node() can be called for NUMA_NO_NODE inside do_map_benchmark() resulting in the following sanitizer report: UBSAN: array-index-out-of-bounds in ./arch/x86/include/asm/topology.h:72:28 index -1 is out of range for type 'cpumask [64][1]' CPU: 1 PID: 990 Comm: dma_map_benchma Not tainted 6.9.0-rc6 #29 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:117) ubsan_epilogue (lib/ubsan.c:232) __ubsan_handle_out_of_bounds (lib/ubsan.c:429) cpumask_of_node (arch/x86/include/asm/topology.h:72) [inline] do_map_benchmark (kernel/dma/map_benchmark.c:104) map_benchmark_ioctl (kernel/dma/map_benchmark.c:246) full_proxy_unlocked_ioctl (fs/debugfs/file.c:333) __x64_sys_ioctl (fs/ioctl.c:890) do_syscall_64 (arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Use cpumask_of_node() in place when binding a kernel thread to a cpuset of a particular node. Note that the provided node id is checked inside map_benchmark_ioctl(). It's just a NUMA_NO_NODE case which is not handled properly later. Found by Linux Verification Center (linuxtesting.org).

In the Linux kernel, the following vulnerability has been resolved: 9p: add missing locking around taking dentry fid list Fix a use-after-free on dentry's d_fsdata fid list when a thread looks up a fid through dentry while another thread unlinks it: UAF thread: refcount_t: addition on 0; use-after-free. p9_fid_get linux/./include/net/9p/client.h:262 v9fs_fid_find+0x236/0x280 linux/fs/9p/fid.c:129 v9fs_fid_lookup_with_uid linux/fs/9p/fid.c:181 v9fs_fid_lookup+0xbf/0xc20 linux/fs/9p/fid.c:314 v9fs_vfs_getattr_dotl+0xf9/0x360 linux/fs/9p/vfs_inode_dotl.c:400 vfs_statx+0xdd/0x4d0 linux/fs/stat.c:248 Freed by: p9_fid_destroy (inlined) p9_client_clunk+0xb0/0xe0 linux/net/9p/client.c:1456 p9_fid_put linux/./include/net/9p/client.h:278 v9fs_dentry_release+0xb5/0x140 linux/fs/9p/vfs_dentry.c:55 v9fs_remove+0x38f/0x620 linux/fs/9p/vfs_inode.c:518 vfs_unlink+0x29a/0x810 linux/fs/namei.c:4335 The problem is that d_fsdata was not accessed under d_lock, because d_release() normally is only called once the dentry is otherwise no longer accessible but since we also call it explicitly in v9fs_remove that lock is required: move the hlist out of the dentry under lock then unref its fids once they are no longer accessible.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix potential index out of bounds in color transformation function Fixes index out of bounds issue in the color transformation function. The issue could occur when the index 'i' exceeds the number of transfer function points (TRANSFER_FUNC_POINTS). The fix adds a check to ensure 'i' is within bounds before accessing the transfer function points. If 'i' is out of bounds, an error message is logged and the function returns false to indicate an error. Reported by smatch: drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:405 cm_helper_translate_curve_to_hw_format() error: buffer overflow 'output_tf->tf_pts.red' 1025 <= s32max drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:406 cm_helper_translate_curve_to_hw_format() error: buffer overflow 'output_tf->tf_pts.green' 1025 <= s32max drivers/gpu/drm/amd/amdgpu/../display/dc/dcn10/dcn10_cm_common.c:407 cm_helper_translate_curve_to_hw_format() error: buffer overflow 'output_tf->tf_pts.blue' 1025 <= s32max

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Discard command completions in internal error Fix use after free when FW completion arrives while device is in internal error state. Avoid calling completion handler in this case, since the device will flush the command interface and trigger all completions manually. Kernel log: ------------[ cut here ]------------ refcount_t: underflow; use-after-free. ... RIP: 0010:refcount_warn_saturate+0xd8/0xe0 ... Call Trace: <IRQ> ? __warn+0x79/0x120 ? refcount_warn_saturate+0xd8/0xe0 ? report_bug+0x17c/0x190 ? handle_bug+0x3c/0x60 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 ? refcount_warn_saturate+0xd8/0xe0 cmd_ent_put+0x13b/0x160 [mlx5_core] mlx5_cmd_comp_handler+0x5f9/0x670 [mlx5_core] cmd_comp_notifier+0x1f/0x30 [mlx5_core] notifier_call_chain+0x35/0xb0 atomic_notifier_call_chain+0x16/0x20 mlx5_eq_async_int+0xf6/0x290 [mlx5_core] notifier_call_chain+0x35/0xb0 atomic_notifier_call_chain+0x16/0x20 irq_int_handler+0x19/0x30 [mlx5_core] __handle_irq_event_percpu+0x4b/0x160 handle_irq_event+0x2e/0x80 handle_edge_irq+0x98/0x230 __common_interrupt+0x3b/0xa0 common_interrupt+0x7b/0xa0 </IRQ> <TASK> asm_common_interrupt+0x22/0x40

In the Linux kernel before 2.6.34, a range check issue in drivers/gpu/drm/radeon/atombios.c could cause an off by one (buffer overflow) problem. NOTE: At least one Linux maintainer believes that this CVE is incorrectly assigned and should be rejected because the value is hard coded and are not user-controllable where it is used

In the Linux kernel, the following vulnerability has been resolved: drivers/perf: hisi: hns3: Fix out-of-bound access when valid event group The perf tool allows users to create event groups through following cmd [1], but the driver does not check whether the array index is out of bounds when writing data to the event_group array. If the number of events in an event_group is greater than HNS3_PMU_MAX_HW_EVENTS, the memory write overflow of event_group array occurs. Add array index check to fix the possible array out of bounds violation, and return directly when write new events are written to array bounds. There are 9 different events in an event_group. [1] perf stat -e '{pmu/event1/, ... ,pmu/event9/}

In the Linux kernel, the following vulnerability has been resolved: stm class: Fix a double free in stm_register_device() The put_device(&stm->dev) call will trigger stm_device_release() which frees "stm" so the vfree(stm) on the next line is a double free.

In the Linux kernel, the following vulnerability has been resolved: wifi: nl80211: Avoid address calculations via out of bounds array indexing Before request->channels[] can be used, request->n_channels must be set. Additionally, address calculations for memory after the "channels" array need to be calculated from the allocation base ("request") rather than via the first "out of bounds" index of "channels", otherwise run-time bounds checking will throw a warning.

In the Linux kernel, the following vulnerability has been resolved: RDMA/hns: Fix UAF for cq async event The refcount of CQ is not protected by locks. When CQ asynchronous events and CQ destruction are concurrent, CQ may have been released, which will cause UAF. Use the xa_lock() to protect the CQ refcount.

In the Linux kernel, the following vulnerability has been resolved: rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow There is a possibility of buffer overflow in show_rcu_tasks_trace_gp_kthread() if counters, passed to sprintf() are huge. Counter numbers, needed for this are unrealistically high, but buffer overflow is still possible. Use snprintf() with buffer size instead of sprintf(). Found by Linux Verification Center (linuxtesting.org) with SVACE.

In the Linux kernel, the following vulnerability has been resolved: iio: adc: PAC1934: fix accessing out of bounds array index Fix accessing out of bounds array index for average current and voltage measurements. The device itself has only 4 channels, but in sysfs there are "fake" channels for the average voltages and currents too.

In the Linux kernel, the following vulnerability has been resolved: net: fix __dst_negative_advice() race __dst_negative_advice() does not enforce proper RCU rules when sk->dst_cache must be cleared, leading to possible UAF. RCU rules are that we must first clear sk->sk_dst_cache, then call dst_release(old_dst). Note that sk_dst_reset(sk) is implementing this protocol correctly, while __dst_negative_advice() uses the wrong order. Given that ip6_negative_advice() has special logic against RTF_CACHE, this means each of the three ->negative_advice() existing methods must perform the sk_dst_reset() themselves. Note the check against NULL dst is centralized in __dst_negative_advice(), there is no need to duplicate it in various callbacks. Many thanks to Clement Lecigne for tracking this issue. This old bug became visible after the blamed commit, using UDP sockets.

In the Linux kernel, the following vulnerability has been resolved: tracefs: Reset permissions on remount if permissions are options There's an inconsistency with the way permissions are handled in tracefs. Because the permissions are generated when accessed, they default to the root inode's permission if they were never set by the user. If the user sets the permissions, then a flag is set and the permissions are saved via the inode (for tracefs files) or an internal attribute field (for eventfs). But if a remount happens that specify the permissions, all the files that were not changed by the user gets updated, but the ones that were are not. If the user were to remount the file system with a given permission, then all files and directories within that file system should be updated. This can cause security issues if a file's permission was updated but the admin forgot about it. They could incorrectly think that remounting with permissions set would update all files, but miss some. For example: # cd /sys/kernel/tracing # chgrp 1002 current_tracer # ls -l [..] -rw-r----- 1 root root 0 May 1 21:25 buffer_size_kb -rw-r----- 1 root root 0 May 1 21:25 buffer_subbuf_size_kb -r--r----- 1 root root 0 May 1 21:25 buffer_total_size_kb -rw-r----- 1 root lkp 0 May 1 21:25 current_tracer -rw-r----- 1 root root 0 May 1 21:25 dynamic_events -r--r----- 1 root root 0 May 1 21:25 dyn_ftrace_total_info -r--r----- 1 root root 0 May 1 21:25 enabled_functions Where current_tracer now has group "lkp". # mount -o remount,gid=1001 . # ls -l -rw-r----- 1 root tracing 0 May 1 21:25 buffer_size_kb -rw-r----- 1 root tracing 0 May 1 21:25 buffer_subbuf_size_kb -r--r----- 1 root tracing 0 May 1 21:25 buffer_total_size_kb -rw-r----- 1 root lkp 0 May 1 21:25 current_tracer -rw-r----- 1 root tracing 0 May 1 21:25 dynamic_events -r--r----- 1 root tracing 0 May 1 21:25 dyn_ftrace_total_info -r--r----- 1 root tracing 0 May 1 21:25 enabled_functions Everything changed but the "current_tracer". Add a new link list that keeps track of all the tracefs_inodes which has the permission flags that tell if the file/dir should use the root inode's permission or not. Then on remount, clear all the flags so that the default behavior of using the root inode's permission is done for all files and directories.