Red Hat Bugzilla – Bug 647416
CVE-2010-3865 kernel: iovec integer overflow in net/rds/rdma.c
Last modified: 2015-02-16 10:46:57 EST
As reported by Thomas Pollet, the rdma page counting can overflow. We get the rdma sizes in 64-bit unsigned entities, but then limit it to UINT_MAX bytes and shift them down to pages (so with a possible "+1" for an unaligned address). So each individual page count fits comfortably in an 'unsigned int' (not even close to overflowing into signed), but as they are added up, they might end up resulting in a signed return value. Which would be wrong. Catch the case of tot_pages turning negative, and return the appropriate error code. http://www.spinics.net/lists/netdev/msg145359.html http://www.spinics.net/lists/netdev/msg145397.html Introduced in commit eff5f53bef75c0864a5da06bb688939092b848dc (v2.6.30-rc1) Acknowledgements: Red Hat would like to thank Thomas Pollet for reporting this issue.
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. Future kernel updates in Red Hat Enterprise Linux 5 may 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
Upstream commit: http://git.kernel.org/linus/1b1f693d7ad6d193862dcb1118540a030c5e761f
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Via RHSA-2011:0004 https://rhn.redhat.com/errata/RHSA-2011-0004.html
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2011:0007 https://rhn.redhat.com/errata/RHSA-2011-0007.html