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xfs: ioctl check for capabilities in the current user namespace

PATCH Superseded Dwight Engen 2 participants 2 messages Jul 17, 2013 – Jul 19, 2013

Subsystems (2)
XFS filesystem Capabilities

v4 of 8 Superseded Latest is v8 →

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Dwight Engen

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#0 lore raw

PATCH v4 3/7 xfs: ioctl check for capabilities in the current user namespace

Use inode_capable() to check if SUID|SGID bits should be cleared to match similar check in inode_change_ok().

The check for CAP_LINUX_IMMUTABLE was not modified since all other file systems also check against init_user_ns rather than current_user_ns.

Signed-off-by Dwight Engen <[email protected]>
---
 fs/xfs/xfs_ioctl.c  | 4 ++--
 kernel/capability.c | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)
fs/xfs/xfs_ioctl.c +2 -2
index 6e2bca5..8edc780 100644
@@ -981,7 +981,7 @@ xfs_ioctl_setattr(
 	 * to the file owner ID, except in cases where the
 	 * CAP_FSETID capability is applicable.
 	 */
-	if (current_fsuid() != ip->i_d.di_uid && !capable(CAP_FOWNER)) {
+	if (!inode_owner_or_capable(VFS_I(ip))) {
 		code = XFS_ERROR(EPERM);
 		goto error_return;
 	}

@@ -1103,7 +1103,7 @@ xfs_ioctl_setattr(
 		 * cleared upon successful return from chown()
 		 */
 		if ((ip->i_d.di_mode & (S_ISUID|S_ISGID)) &&
-		    !capable(CAP_FSETID))
+		    !inode_capable(VFS_I(ip), CAP_FSETID))
 			ip->i_d.di_mode &= ~(S_ISUID|S_ISGID);
 
 		/*
kernel/capability.c +1 -0
index f6c2ce5..a4b6744 100644
@@ -464,3 +464,4 @@ bool inode_capable(const struct inode *inode, int cap)
 
 	return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid);
 }
+EXPORT_SYMBOL(inode_capable);
Signature · 6 lines
1.8.1.4

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Reviewed-by on v4 3/7
#1 lore raw
Quoted 39 lines · Dwight Engen

Use inode_capable() to check if SUID|SGID bits should be cleared to match similar check in inode_change_ok().

The check for CAP_LINUX_IMMUTABLE was not modified since all other file systems also check against init_user_ns rather than current_user_ns.

Signed-off-by Dwight Engen <[email protected]>
---
 fs/xfs/xfs_ioctl.c  | 4 ++--
 kernel/capability.c | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)
fs/xfs/xfs_ioctl.c +2 -2
index 6e2bca5..8edc780 100644
@@ -981,7 +981,7 @@ xfs_ioctl_setattr(
 	 * to the file owner ID, except in cases where the
 	 * CAP_FSETID capability is applicable.
 	 */
-	if (current_fsuid() != ip->i_d.di_uid && !capable(CAP_FOWNER)) {
+	if (!inode_owner_or_capable(VFS_I(ip))) {
 		code = XFS_ERROR(EPERM);
 		goto error_return;
 	}

@@ -1103,7 +1103,7 @@ xfs_ioctl_setattr(
 		 * cleared upon successful return from chown()
 		 */
 		if ((ip->i_d.di_mode & (S_ISUID|S_ISGID)) &&
-		    !capable(CAP_FSETID))
+		    !inode_capable(VFS_I(ip), CAP_FSETID))
 			ip->i_d.di_mode &= ~(S_ISUID|S_ISGID);
 
 		/*
kernel/capability.c +0 -0
index f6c2ce5..a4b6744 100644

kernel/capability.c bool inode_capable(const struct inode *inode, int cap) · line 467

Quoted 4 lines
kernel/capability.c +1 -0
@@ -464,3 +464,4 @@ bool inode_capable(const struct inode *inode, int cap)
 
 	return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid);
 }
+EXPORT_SYMBOL(inode_capable);

Looks good. I'm surprised that no-one else has needed this exported; there are several non-core !capable(CAP_FSETID) checks that are similar to this one that weren't converted to inode_capable() checks, yet the core inode_change_ok()/setattr_copy() code was...

Regardless,

Reviewed-by Dave Chinner <[email protected]>

Cheers,

Dave.

Signature · 7 lines
Dave Chinner
[email protected]

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