Author: kib Date: Fri Feb 8 04:18:17 2019 New Revision: 343891 URL: https://svnweb.freebsd.org/changeset/base/343891
Log: Fix renameat(2) for CAPABILITIES kernels. When renameat(2) is used with: - absolute path for to; - tofd not set to AT_FDCWD; - the target exists kern_renameat() requires CAP_UNLINK capability on tofd, but corresponding namei ni_filecap is not initialized at all because the lookup is absolute. As result, the check was done against empty filecap and syscall fails erronously. Fix it by creating a return flags namei member and reporting if the lookup was absolute, then do not touch to.ni_filecaps at all. PR: 222258 Reviewed by: jilles, ngie Sponsored by: The FreeBSD Foundation MFC after: 1 week X-MFC-note: KBI breakage Differential revision: https://reviews.freebsd.org/D19096 Modified: head/sys/kern/vfs_lookup.c head/sys/kern/vfs_syscalls.c head/sys/sys/namei.h Modified: head/sys/kern/vfs_lookup.c ============================================================================== --- head/sys/kern/vfs_lookup.c Fri Feb 8 04:06:48 2019 (r343890) +++ head/sys/kern/vfs_lookup.c Fri Feb 8 04:18:17 2019 (r343891) @@ -410,6 +410,7 @@ namei(struct nameidata *ndp) dp = NULL; cnp->cn_nameptr = cnp->cn_pnbuf; if (cnp->cn_pnbuf[0] == '/') { + ndp->ni_resflags |= NIRES_ABS; error = namei_handle_root(ndp, &dp); } else { if (ndp->ni_startdir != NULL) { @@ -1302,6 +1303,7 @@ NDINIT_ALL(struct nameidata *ndp, u_long op, u_long fl ndp->ni_dirp = namep; ndp->ni_dirfd = dirfd; ndp->ni_startdir = startdir; + ndp->ni_resflags = 0; filecaps_init(&ndp->ni_filecaps); ndp->ni_cnd.cn_thread = td; if (rightsp != NULL) Modified: head/sys/kern/vfs_syscalls.c ============================================================================== --- head/sys/kern/vfs_syscalls.c Fri Feb 8 04:06:48 2019 (r343890) +++ head/sys/kern/vfs_syscalls.c Fri Feb 8 04:18:17 2019 (r343891) @@ -3544,10 +3544,10 @@ again: goto out; } #ifdef CAPABILITIES - if (newfd != AT_FDCWD) { + if (newfd != AT_FDCWD && (tond.ni_resflags & NIRES_ABS) == 0) { /* * If the target already exists we require CAP_UNLINKAT - * from 'newfd'. + * from 'newfd', when newfd was used for the lookup. */ error = cap_check(&tond.ni_filecaps.fc_rights, &cap_unlinkat_rights); Modified: head/sys/sys/namei.h ============================================================================== --- head/sys/sys/namei.h Fri Feb 8 04:06:48 2019 (r343890) +++ head/sys/sys/namei.h Fri Feb 8 04:18:17 2019 (r343891) @@ -88,6 +88,10 @@ struct nameidata { struct vnode *ni_vp; /* vnode of result */ struct vnode *ni_dvp; /* vnode of intermediate directory */ /* + * Results: flags returned from namei + */ + u_int ni_resflags; + /* * Shared between namei and lookup/commit routines. */ size_t ni_pathlen; /* remaining chars in path */ @@ -158,6 +162,11 @@ struct nameidata { #define TRAILINGSLASH 0x10000000 /* path ended in a slash */ #define NOCAPCHECK 0x20000000 /* do not perform capability checks */ #define PARAMASK 0x3ffffe00 /* mask of parameter descriptors */ + +/* + * Namei results flags + */ +#define NIRES_ABS 0x00000001 /* Path was absolute */ /* * Flags in ni_lcf, valid for the duration of the namei call. _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
