From: Serge E. Hallyn Date: Tue, 29 Dec 2009 20:50:19 +0000 (-0600) Subject: generic_permission: MAY_OPEN is not write access X-Git-Tag: firefly_0821_release~11625^2~386 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=84d330ec80dc467baf6cb393d9c1ee006d1c024a;p=firefly-linux-kernel-4.4.55.git generic_permission: MAY_OPEN is not write access commit 7ea6600148c265b1fd53e521022b1d7aec81d974 upstream. 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 Signed-off-by: Serge E. Hallyn Tested-by: Mike Kazantsev Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/namei.c b/fs/namei.c index d11f404667e9..a2b3c28a499d 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -234,6 +234,7 @@ 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;