Author: mjg
Date: Tue Aug 11 01:34:40 2020
New Revision: 364095
URL: https://svnweb.freebsd.org/changeset/base/364095
Log:
vfs: stricter validation for flags passed to namei in cn_flags
namei de facto expects that the naimeidata object is properly initialized,
but at the same time it mixes consumer-passable and internal flags, while
tolerating this part by explicitly clearing some of them.
Tighten the interface instead.
While here renumber the flags and denote the gap between the 2 variants.
Try to piggy back th renumber on the just bumped __FreeBSD_version.
Modified:
head/sys/kern/vfs_lookup.c
head/sys/sys/namei.h
Modified: head/sys/kern/vfs_lookup.c
==============================================================================
--- head/sys/kern/vfs_lookup.c Tue Aug 11 01:09:06 2020 (r364094)
+++ head/sys/kern/vfs_lookup.c Tue Aug 11 01:34:40 2020 (r364095)
@@ -61,6 +61,9 @@ __FBSDID("$FreeBSD$");
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
+#ifdef INVARIANTS
+#include <machine/_inttypes.h>
+#endif
#include <security/audit/audit.h>
#include <security/mac/mac_framework.h>
@@ -484,14 +487,14 @@ namei(struct nameidata *ndp)
("namei: nameiop contaminated with flags"));
KASSERT((cnp->cn_flags & OPMASK) == 0,
("namei: flags contaminated with nameiops"));
+ KASSERT((cnp->cn_flags & NAMEI_INTERNAL_FLAGS) == 0,
+ ("namei: unexpected flags: %" PRIx64 "\n",
+ cnp->cn_flags & NAMEI_INTERNAL_FLAGS));
if (cnp->cn_flags & NOCACHE)
KASSERT(cnp->cn_nameiop != LOOKUP,
("%s: NOCACHE passed with LOOKUP", __func__));
MPASS(ndp->ni_startdir == NULL || ndp->ni_startdir->v_type == VDIR ||
ndp->ni_startdir->v_type == VBAD);
-
- /* We will set this ourselves if we need it. */
- cnp->cn_flags &= ~TRAILINGSLASH;
ndp->ni_lcf = 0;
ndp->ni_vp = NULL;
Modified: head/sys/sys/namei.h
==============================================================================
--- head/sys/sys/namei.h Tue Aug 11 01:09:06 2020 (r364094)
+++ head/sys/sys/namei.h Tue Aug 11 01:34:40 2020 (r364095)
@@ -152,22 +152,31 @@ int cache_fplookup(struct nameidata *ndp, enum
cache_f
#define HASBUF 0x00000400 /* has allocated pathname buffer */
#define SAVENAME 0x00000800 /* save pathname buffer */
#define SAVESTART 0x00001000 /* save starting directory */
-#define ISDOTDOT 0x00002000 /* current component name is .. */
-#define MAKEENTRY 0x00004000 /* entry is to be added to name
cache */
-#define ISLASTCN 0x00008000 /* this is last component of
pathname */
-#define ISSYMLINK 0x00010000 /* symlink needs interpretation */
-#define ISWHITEOUT 0x00020000 /* found whiteout */
-#define DOWHITEOUT 0x00040000 /* do whiteouts */
-#define WILLBEDIR 0x00080000 /* new files will be dirs; allow
trailing / */
-#define ISOPEN 0x00200000 /* caller is opening; return a real
vnode. */
-#define NOCROSSMOUNT 0x00400000 /* do not cross mount points */
-#define NOMACCHECK 0x00800000 /* do not perform MAC checks */
-#define AUDITVNODE1 0x04000000 /* audit the looked up vnode
information */
-#define AUDITVNODE2 0x08000000 /* audit the looked up vnode
information */
-#define TRAILINGSLASH 0x10000000 /* path ended in a slash */
-#define NOCAPCHECK 0x20000000 /* do not perform capability checks
*/
-#define NOEXECCHECK 0x40000000 /* do not perform exec check on dir
*/
+#define ISWHITEOUT 0x00002000 /* found whiteout */
+#define DOWHITEOUT 0x00004000 /* do whiteouts */
+#define WILLBEDIR 0x00008000 /* new files will be dirs; allow
trailing / */
+#define ISOPEN 0x00010000 /* caller is opening; return a real
vnode. */
+#define NOCROSSMOUNT 0x00020000 /* do not cross mount points */
+#define NOMACCHECK 0x00040000 /* do not perform MAC checks */
+#define AUDITVNODE1 0x00080000 /* audit the looked up vnode
information */
+#define AUDITVNODE2 0x00100000 /* audit the looked up vnode
information */
+#define NOCAPCHECK 0x00200000 /* do not perform capability checks
*/
+/* UNUSED 0x00400000 */
+/* UNUSED 0x00800000 */
+/* UNUSED 0x01000000 */
+#define NOEXECCHECK 0x02000000 /* do not perform exec check on dir
*/
+#define MAKEENTRY 0x04000000 /* entry is to be added to name
cache */
+#define ISSYMLINK 0x08000000 /* symlink needs interpretation */
+#define ISLASTCN 0x10000000 /* this is last component of
pathname */
+#define ISDOTDOT 0x20000000 /* current component name is .. */
+#define TRAILINGSLASH 0x40000000 /* path ended in a slash */
#define PARAMASK 0x7ffffe00 /* mask of parameter descriptors */
+
+/*
+ * Flags which must not be passed in by callers.
+ */
+#define NAMEI_INTERNAL_FLAGS \
+ (NOEXECCHECK | MAKEENTRY | ISSYMLINK | ISLASTCN | ISDOTDOT |
TRAILINGSLASH)
/*
* Namei results flags
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