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[ Upstream commitce51c81700] The functions iscsi_if_set_param() and iscsi_if_set_host_param() convert an nlattr payload to type char* and then call C string handling functions like sscanf and kstrdup: char *data = (char*)ev + sizeof(*ev); ... sscanf(data, "%d", &value); However, since the nlattr is provided by the user-space program and the nlmsg skb is allocated with GFP_KERNEL instead of GFP_ZERO flag (see netlink_alloc_large_skb() in netlink_sendmsg()), dirty data on the heap can lead to an OOB access for those string handling functions. By investigating how the bug is introduced, we find it is really interesting as the old version parsing code starting from commitfd7255f51a("[SCSI] iscsi: add sysfs attrs for uspace sync up") treated the nlattr as integer bytes instead of string and had length check in iscsi_copy_param(): if (ev->u.set_param.len != sizeof(uint32_t)) BUG(); But, since the commita54a52caad("[SCSI] iscsi: fixup set/get param functions"), the code treated the nlattr as C string while forgetting to add any strlen checks(), opening the possibility of an OOB access. Fix the potential OOB by adding the strlen() check before accessing the buf. If the data passes this check, all low-level set_param handlers can safely treat this buf as legal C string. Fixes:fd7255f51a("[SCSI] iscsi: add sysfs attrs for uspace sync up") Fixes:1d9bf13a9c("[SCSI] iscsi class: add iscsi host set param event") Signed-off-by: Lin Ma <linma@zju.edu.cn> Link: https://lore.kernel.org/r/20230723075820.3713119-1-linma@zju.edu.cn Reviewed-by: Chris Leech <cleech@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.