CVE-2010-3904
Description
From CVE.org
The rds_page_copy_user function in net/rds/page.c in the Reliable Datagram Sockets (RDS) protocol implementation in the Linux kernel before 2.6.36 does not properly validate addresses obtained from user space, which allows local users to gain privileges via crafted use of the sendmsg and recvmsg system calls.
Statement
The Linux kernel as shipped with Red Hat Enterprise Linux 3, 4 and Red Hat Enterprise MRG did not include support for the RDS Protocol, and therefore are not affected by this issue. Updates for Red Hat Enterprise Linux 5 and 6 are available to address this flaw.
Mitigation
For users that do not run applications that use RDS, you can prevent the rds module from being loaded by adding the following entry to the end of the /etc/modprobe.d/blacklist file:
blacklist rds
This way, the rds module cannot be loaded accidentally, which may occur if an application that requires RDS is started. A reboot is not necessary for this change to take effect but do make sure the module is not loaded in the first place. You can verify that by running:
lsmod | grep rds
You may also consider removing the CAP_SYS_MODULE capability from the current global capability set to prevent kernel modules from being loaded or unloaded. The CAP_SYS_MODULE has a capability number of 16 (see linux/capability.h). The default value has all the bits set. To remove this capability, you have to clear the 16th bit of the default 32-bit value, e.g. 0xffffff ^ (1 << 16):
echo 0xFFFEFFFF > /proc/sys/kernel/cap-bound
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.2 | 7.2 | N/A |
| Attack Vector | Local | Local | N/A |
| Access Complexity | Low | Low | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | Complete | Complete | N/A |
| Integrity Impact | Complete | Complete | N/A |
| Availability Impact | Complete | Complete | N/A |
Vector
Red Hat: AV:L/AC:L/Au:N/C:C/I:C/A:C
NVD: AV:L/AC:L/Au:N/C:C/I:C/A:C
Acknowledgements
Red Hat would like to thank Dan Rosenberg (Virtual Security Research) for reporting this issue.
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