CVE-2022-49771
In the Linux kernel, the following vulnerability has been resolved: dm ioctl: fix misbehavior if list_versions races with module loading __list_versions will first estimate the required space using the "dm_target_iterate(list_version_get_needed,…
Does this matter?
Lower severity and a low EPSS score (0.15%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: dm ioctl: fix misbehavior if list_versions races with module loading __list_versions will first estimate the required space using the "dm_target_iterate(list_version_get_needed, &needed)" call and then will fill the space using the "dm_target_iterate(list_version_get_info, &iter_info)" call. Each of these calls locks the targets using the "down_read(&_lock)" and "up_read(&_lock)" calls, however between the first and second "dm_target_iterate" there is no lock held and the target modules can be loaded at this point, so the second "dm_target_iterate" call may need more space than what was the first "dm_target_iterate" returned. The code tries to handle this overflow (see the beginning of list_version_get_info), however this handling is incorrect. The code sets "param->data_size = param->data_start + needed" and "iter_info.end = (char *)vers+len" - "needed" is the size returned by the first dm_target_iterate call; "len" is the size of the buffer allocated by userspace. "len" may be greater than "needed"; in this case, the code will write up to "len" bytes into the buffer, however param->data_size is set to "needed", so it may write data past the param->data_size value. The ioctl interface copies only up to param->data_size into userspace, thus part of the result will be truncated. Fix this bug by setting "iter_info.end = (char *)vers + needed;" - this guarantees that the second "dm_target_iterate" call will write only up to the "needed" buffer and it will exit with "DM_BUFFER_FULL_FLAG" if it overflows the "needed" space - in this case, userspace will allocate a larger buffer and retry. Note that there is also a bug in list_version_get_needed - we need to add "strlen(tt->name) + 1" to the needed size, not "strlen(tt->name)".
- CVSS 3.1
- 4.7 MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.15% probability · 5th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-362
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0c8d4112df329bf3dfbf27693f918c3b08676538Patch
- https://git.kernel.org/stable/c/3a1c35d72dc0b34d1e746ed705790c0f630aa427Patch
- https://git.kernel.org/stable/c/4fe1ec995483737f3d2a14c3fe1d8fe634972979Patch
- https://git.kernel.org/stable/c/5398b8e275bf81a2517b327d216c0f37ac9ac5aePatch
- https://git.kernel.org/stable/c/6a818db0d5aecf80d4ba9e10ac153f60adc629caPatch
- https://git.kernel.org/stable/c/6ffce7a92ef5c68f7e5d6f4d722c2f96280c064bPatch
- https://git.kernel.org/stable/c/b545c0e1e4094d4de2bdfe9a3823f9154b0c0005Patch
- https://git.kernel.org/stable/c/f59f5a269ca5e43c567aca7f1f52500a0186e9b7Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.