CVE - CVE-2022-49771

CVE-ID
CVE-2022-49771	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
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)".
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/0c8d4112df329bf3dfbf27693f918c3b08676538 URL:https://git.kernel.org/stable/c/0c8d4112df329bf3dfbf27693f918c3b08676538 MISC:https://git.kernel.org/stable/c/3a1c35d72dc0b34d1e746ed705790c0f630aa427 URL:https://git.kernel.org/stable/c/3a1c35d72dc0b34d1e746ed705790c0f630aa427 MISC:https://git.kernel.org/stable/c/4fe1ec995483737f3d2a14c3fe1d8fe634972979 URL:https://git.kernel.org/stable/c/4fe1ec995483737f3d2a14c3fe1d8fe634972979 MISC:https://git.kernel.org/stable/c/5398b8e275bf81a2517b327d216c0f37ac9ac5ae URL:https://git.kernel.org/stable/c/5398b8e275bf81a2517b327d216c0f37ac9ac5ae MISC:https://git.kernel.org/stable/c/6a818db0d5aecf80d4ba9e10ac153f60adc629ca URL:https://git.kernel.org/stable/c/6a818db0d5aecf80d4ba9e10ac153f60adc629ca MISC:https://git.kernel.org/stable/c/6ffce7a92ef5c68f7e5d6f4d722c2f96280c064b URL:https://git.kernel.org/stable/c/6ffce7a92ef5c68f7e5d6f4d722c2f96280c064b MISC:https://git.kernel.org/stable/c/b545c0e1e4094d4de2bdfe9a3823f9154b0c0005 URL:https://git.kernel.org/stable/c/b545c0e1e4094d4de2bdfe9a3823f9154b0c0005 MISC:https://git.kernel.org/stable/c/f59f5a269ca5e43c567aca7f1f52500a0186e9b7 URL:https://git.kernel.org/stable/c/f59f5a269ca5e43c567aca7f1f52500a0186e9b7
Assigning CNA
kernel.org
Date Record Created
20250416	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250416)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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