Commit 76a67ec6 authored Mar 16, 2009 by J. Bruce Fields

nfsd: nfsd should drop CAP_MKNOD for non-root



Since creating a device node is normally an operation requiring special
privilege, Igor Zhbanov points out that it is surprising (to say the
least) that a client can, for example, create a device node on a
filesystem exported with root_squash.

So, make sure CAP_MKNOD is among the capabilities dropped when an nfsd
thread handles a request from a non-root user.

Reported-by: Igor Zhbanov <izh1979@gmail.com>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

parent 84f09f46

include/linux/capability.h

+4 −2

Original line number	Diff line number	Diff line
		@@ -393,7 +393,9 @@ struct cpu_vfs_cap_data {
		# define CAP_FULL_SET ((kernel_cap_t){{ ~0, ~0 }})
		# define CAP_INIT_EFF_SET ((kernel_cap_t){{ ~CAP_TO_MASK(CAP_SETPCAP), ~0 }})
		# define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0, CAP_FS_MASK_B1 } })
		# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0\|CAP_TO_MASK(CAP_SYS_RESOURCE), \
		# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
		\| CAP_TO_MASK(CAP_SYS_RESOURCE) \
		\| CAP_TO_MASK(CAP_MKNOD), \
		CAP_FS_MASK_B1 } })

		#endif /* _KERNEL_CAPABILITY_U32S != 2 */