Commit 7ea66001 authored Dec 29, 2009 by Serge E. Hallyn Committed by Linus Torvalds Dec 30, 2009

generic_permission: MAY_OPEN is not write access



generic_permission was refusing CAP_DAC_READ_SEARCH-enabled
processes from opening DAC-protected files read-only, because
do_filp_open adds MAY_OPEN to the open mask.

Ignore MAY_OPEN.  After this patch, CAP_DAC_READ_SEARCH is
again sufficient to open(fname, O_RDONLY) on a file to which
DAC otherwise refuses us read permission.

Reported-by: Mike Kazantsev <mk.fraggod@gmail.com>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Mike Kazantsev <mk.fraggod@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 9a7262a0

fs/namei.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -232,6 +232,7 @@ int generic_permission(struct inode *inode, int mask,
		/*
		* Searching includes executable on directories, else just read.
		*/
		mask &= MAY_READ \| MAY_WRITE \| MAY_EXEC;
		if (mask == MAY_READ \|\| (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
		if (capable(CAP_DAC_READ_SEARCH))
		return 0;