git: 57093f9366b7 - main - vfs: Consistently validate AT_* flags in kern_* functions.

The branch main has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=57093f9366b7eeb48054ff2fa77b9d01d2b3cfc2

commit 57093f9366b7eeb48054ff2fa77b9d01d2b3cfc2
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2021-11-09 17:42:12 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2021-11-09 17:42:12 +0000

    vfs: Consistently validate AT_* flags in kern_* functions.
    
    Some syscalls checked for invalid AT_* flags in sys_* and others in
    kern_*.
    
    Reviewed by:    kib
    Obtained from:  CheriBSD
    Sponsored by:   The University of Cambridge, Google Inc.
    Differential Revision:  https://reviews.freebsd.org/D32864
---
 sys/kern/vfs_syscalls.c | 40 +++++++++++++++++++---------------------
 1 file changed, 19 insertions(+), 21 deletions(-)

diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 29a6b34d083a..cedadc55b87f 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -1524,15 +1524,9 @@ struct linkat_args {
 int
 sys_linkat(struct thread *td, struct linkat_args *uap)
 {
-	int flag;
-
-	flag = uap->flag;
-	if ((flag & ~(AT_SYMLINK_FOLLOW | AT_RESOLVE_BENEATH |
-	    AT_EMPTY_PATH)) != 0)
-		return (EINVAL);
 
 	return (kern_linkat(td, uap->fd1, uap->fd2, uap->path1, uap->path2,
-	    UIO_USERSPACE, flag));
+	    UIO_USERSPACE, uap->flag));
 }
 
 int hardlink_check_uid = 0;
@@ -1581,6 +1575,10 @@ kern_linkat(struct thread *td, int fd1, int fd2, const char *path1,
 	struct nameidata nd;
 	int error;
 
+	if ((flag & ~(AT_SYMLINK_FOLLOW | AT_RESOLVE_BENEATH |
+	    AT_EMPTY_PATH)) != 0)
+		return (EINVAL);
+
 	NDPREINIT(&nd);
 	do {
 		bwillwrite();
@@ -2758,10 +2756,6 @@ int
 sys_chflagsat(struct thread *td, struct chflagsat_args *uap)
 {
 
-	if ((uap->atflag & ~(AT_SYMLINK_NOFOLLOW | AT_RESOLVE_BENEATH |
-	    AT_EMPTY_PATH)) != 0)
-		return (EINVAL);
-
 	return (kern_chflagsat(td, uap->fd, uap->path, UIO_USERSPACE,
 	    uap->flags, uap->atflag));
 }
@@ -2790,6 +2784,10 @@ kern_chflagsat(struct thread *td, int fd, const char *path,
 	struct nameidata nd;
 	int error;
 
+	if ((atflag & ~(AT_SYMLINK_NOFOLLOW | AT_RESOLVE_BENEATH |
+	    AT_EMPTY_PATH)) != 0)
+		return (EINVAL);
+
 	AUDIT_ARG_FFLAGS(flags);
 	NDINIT_ATRIGHTS(&nd, LOOKUP, at2cnpflags(atflag, AT_SYMLINK_NOFOLLOW |
 	    AT_RESOLVE_BENEATH | AT_EMPTY_PATH) | AUDITVNODE1, pathseg, path,
@@ -2889,10 +2887,6 @@ int
 sys_fchmodat(struct thread *td, struct fchmodat_args *uap)
 {
 
-	if ((uap->flag & ~(AT_SYMLINK_NOFOLLOW | AT_RESOLVE_BENEATH |
-	    AT_EMPTY_PATH)) != 0)
-		return (EINVAL);
-
 	return (kern_fchmodat(td, uap->fd, uap->path, UIO_USERSPACE,
 	    uap->mode, uap->flag));
 }
@@ -2921,6 +2915,10 @@ kern_fchmodat(struct thread *td, int fd, const char *path,
 	struct nameidata nd;
 	int error;
 
+	if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_RESOLVE_BENEATH |
+	    AT_EMPTY_PATH)) != 0)
+		return (EINVAL);
+
 	AUDIT_ARG_MODE(mode);
 	NDINIT_ATRIGHTS(&nd, LOOKUP, at2cnpflags(flag, AT_SYMLINK_NOFOLLOW |
 	    AT_RESOLVE_BENEATH | AT_EMPTY_PATH) | AUDITVNODE1, pathseg, path,
@@ -3018,10 +3016,6 @@ int
 sys_fchownat(struct thread *td, struct fchownat_args *uap)
 {
 
-	if ((uap->flag & ~(AT_SYMLINK_NOFOLLOW | AT_RESOLVE_BENEATH |
-	    AT_EMPTY_PATH)) != 0)
-		return (EINVAL);
-
 	return (kern_fchownat(td, uap->fd, uap->path, UIO_USERSPACE, uap->uid,
 	    uap->gid, uap->flag));
 }
@@ -3033,6 +3027,10 @@ kern_fchownat(struct thread *td, int fd, const char *path,
 	struct nameidata nd;
 	int error;
 
+	if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_RESOLVE_BENEATH |
+	    AT_EMPTY_PATH)) != 0)
+		return (EINVAL);
+
 	AUDIT_ARG_OWNER(uid, gid);
 	NDINIT_ATRIGHTS(&nd, LOOKUP, at2cnpflags(flag, AT_SYMLINK_NOFOLLOW |
 	    AT_RESOLVE_BENEATH | AT_EMPTY_PATH) | AUDITVNODE1, pathseg, path,
@@ -4401,8 +4399,6 @@ int
 sys_getfhat(struct thread *td, struct getfhat_args *uap)
 {
 
-	if ((uap->flags & ~(AT_SYMLINK_NOFOLLOW | AT_RESOLVE_BENEATH)) != 0)
-		return (EINVAL);
 	return (kern_getfhat(td, uap->flags, uap->fd, uap->path, UIO_USERSPACE,
 	    uap->fhp, UIO_USERSPACE));
 }
@@ -4416,6 +4412,8 @@ kern_getfhat(struct thread *td, int flags, int fd, const char *path,
 	struct vnode *vp;
 	int error;
 
+	if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_RESOLVE_BENEATH)) != 0)
+		return (EINVAL);
 	error = priv_check(td, PRIV_VFS_GETFH);
 	if (error != 0)
 		return (error);