permission() bug?

[Andreas Gruenbacher <agruen@suse.de>]

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Hello Andrew,

the fix for permission() that makes it compliant with POSIX.1-2001
apparently was lost. Here is the patch I sent before. (The relevant
lines from the standard text are cited in
http://www.ussg.iu.edu/hypermail/linux/kernel/0310.2/0286.html. The fix
proposed in that posting did not handle directories without execute
permissions correctly.)

Could you please apply the attached patch to mainline? Thanks.


Regards,
-- 
Andreas Gruenbacher <agruen@suse.de>
SUSE Labs, SUSE LINUX AG

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Make permission check conform to POSIX.1-2001

The access(2) function does not conform to POSIX.1-2001: For root
and a file with no permissions, access(file, MAY_READ|MAY_EXEC)
returns 0 (it should return -1).

Index: linux-2.6.0+fix/fs/jfs/acl.c
===================================================================
--- linux-2.6.0+fix.orig/fs/jfs/acl.c	2003-12-18 03:58:07.000000000 +0100
+++ linux-2.6.0+fix/fs/jfs/acl.c	2003-12-27 02:01:56.000000000 +0100
@@ -191,7 +191,8 @@ check_capabilities:
 	 * Read/write DACs are always overridable.
 	 * Executable DACs are overridable if at least one exec bit is set.
 	 */
-	if ((mask & (MAY_READ|MAY_WRITE)) || (inode->i_mode & S_IXUGO))
+	if (!(mask & MAY_EXEC) ||
+	    (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
 		if (capable(CAP_DAC_OVERRIDE))
 			return 0;
 
Index: linux-2.6.0+fix/fs/xfs/xfs_inode.c
===================================================================
--- linux-2.6.0+fix.orig/fs/xfs/xfs_inode.c	2003-12-18 03:59:45.000000000 +0100
+++ linux-2.6.0+fix/fs/xfs/xfs_inode.c	2003-12-27 02:05:00.000000000 +0100
@@ -3722,7 +3722,8 @@ xfs_iaccess(
 	 * Read/write DACs are always overridable.
 	 * Executable DACs are overridable if at least one exec bit is set.
 	 */
-	if ((orgmode & (S_IRUSR|S_IWUSR)) || (inode->i_mode & S_IXUGO))
+	if (!(orgmode & S_IXUSR) || (inode->i_mode & S_IXUGO) ||
+	    (ip->i_d.di_mode & S_IFMT) == S_IFDIR)
 		if (capable_cred(cr, CAP_DAC_OVERRIDE))
 			return 0;
 
Index: linux-2.6.0+fix/fs/ext2/acl.c
===================================================================
--- linux-2.6.0+fix.orig/fs/ext2/acl.c	2003-12-18 03:59:18.000000000 +0100
+++ linux-2.6.0+fix/fs/ext2/acl.c	2003-12-27 02:05:46.000000000 +0100
@@ -322,7 +322,8 @@ check_groups:
 
 check_capabilities:
 	/* Allowed to override Discretionary Access Control? */
-	if ((mask & (MAY_READ|MAY_WRITE)) || (inode->i_mode & S_IXUGO))
+	if (!(mask & MAY_EXEC) ||
+	    (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
 		if (capable(CAP_DAC_OVERRIDE))
 			return 0;
 	/* Read and search granted if capable(CAP_DAC_READ_SEARCH) */
Index: linux-2.6.0+fix/fs/ext3/acl.c
===================================================================
--- linux-2.6.0+fix.orig/fs/ext3/acl.c	2003-12-18 03:58:39.000000000 +0100
+++ linux-2.6.0+fix/fs/ext3/acl.c	2003-12-27 02:07:02.000000000 +0100
@@ -327,7 +327,8 @@ check_groups:
 
 check_capabilities:
 	/* Allowed to override Discretionary Access Control? */
-	if ((mask & (MAY_READ|MAY_WRITE)) || (inode->i_mode & S_IXUGO))
+	if (!(mask & MAY_EXEC) ||
+	    (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
 		if (capable(CAP_DAC_OVERRIDE))
 			return 0;
 	/* Read and search granted if capable(CAP_DAC_READ_SEARCH) */
Index: linux-2.6.0+fix/fs/namei.c
===================================================================
--- linux-2.6.0+fix.orig/fs/namei.c	2003-12-18 03:58:40.000000000 +0100
+++ linux-2.6.0+fix/fs/namei.c	2003-12-27 01:58:23.000000000 +0100
@@ -190,7 +190,8 @@ int vfs_permission(struct inode * inode,
 	 * Read/write DACs are always overridable.
 	 * Executable DACs are overridable if at least one exec bit is set.
 	 */
-	if ((mask & (MAY_READ|MAY_WRITE)) || (inode->i_mode & S_IXUGO))
+	if (!(mask & MAY_EXEC) ||
+	    (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
 		if (capable(CAP_DAC_OVERRIDE))
 			return 0;