CVE-2022-49879

Summary

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

ext4: fix BUG_ON() when directory entry has invalid rec_len

The rec_len field in the directory entry has to be a multiple of 4. A corrupted filesystem image can be used to hit a BUG() in ext4_rec_len_to_disk(), called from make_indexed_dir().

————[ cut here ]———— kernel BUG at fs/ext4/ext4.h:2413! … RIP: 0010:make_indexed_dir+0x53f/0x5f0 … Call Trace: <TASK> ? add_dirent_to_buf+0x1b2/0x200 ext4_add_entry+0x36e/0x480 ext4_add_nondir+0x2b/0xc0 ext4_create+0x163/0x200 path_openat+0x635/0xe90 do_filp_open+0xb4/0x160 ? __create_object.isra.0+0x1de/0x3b0 ? _raw_spin_unlock+0x12/0x30 do_sys_openat2+0x91/0x150 __x64_sys_open+0x6c/0xa0 do_syscall_64+0x3c/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The fix simply adds a call to ext4_check_dir_entry() to validate the directory entry, returning -EFSCORRUPTED if the entry is invalid.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4 < 2fa24d0274fbf913b56ee31f15bc01168669d909affected
LinuxLinux3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4 < 156451a67b93986fb07c274ef6995ff40766c5adaffected
LinuxLinux3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4 < 999cff2b6ce3b45c08abf793bf55534777421327affected
LinuxLinux3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4 < ce1ee2c8827fb6493e91acbd50f664cf2a972c3daffected
LinuxLinux3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4 < 17a0bc9bd697f75cfdf9b378d5eb2d7409c91340affected
LinuxLinux2.6.30affected
LinuxLinux0 < 2.6.30unaffected
LinuxLinux5.4.224 <= 5.4.*unaffected
LinuxLinux5.10.154 <= 5.10.*unaffected
LinuxLinux5.15.78 <= 5.15.*unaffected
LinuxLinux6.0.8 <= 6.0.*unaffected
LinuxLinux6.1 <= *unaffected

Weaknesses

References