Date: Wed, 16 Oct 2019 13:21:02 +0000 (UTC) From: Andrew Turner <andrew@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r353640 - head/sys/kern Message-ID: <201910161321.x9GDL2ee021543@repo.freebsd.org>
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Author: andrew Date: Wed Oct 16 13:21:01 2019 New Revision: 353640 URL: https://svnweb.freebsd.org/changeset/base/353640 Log: Stop leaking information from the kernel through timespec The timespec struct holds a seconds value in a time_t and a nanoseconds value in a long. On most architectures these are the same size, however on 32-bit architectures other than i386 time_t is 8 bytes and long is 4 bytes. Most ABIs will then pad a struct holding an 8 byte and 4 byte value to 16 bytes with 4 bytes of padding. When copying one of these structs the compiler is free to copy the padding if it wishes. In this case the padding may contain kernel data that is then leaked to userspace. Fix this by copying the timespec elements rather than the entire struct. This doesn't affect Tier-1 architectures so no SA is expected. admbugs: 651 MFC after: 1 week Sponsored by: DARPA, AFRL Modified: head/sys/kern/vfs_vnops.c Modified: head/sys/kern/vfs_vnops.c ============================================================================== --- head/sys/kern/vfs_vnops.c Wed Oct 16 13:20:36 2019 (r353639) +++ head/sys/kern/vfs_vnops.c Wed Oct 16 13:21:01 2019 (r353640) @@ -1455,10 +1455,14 @@ vn_stat(struct vnode *vp, struct stat *sb, struct ucre if (vap->va_size > OFF_MAX) return (EOVERFLOW); sb->st_size = vap->va_size; - sb->st_atim = vap->va_atime; - sb->st_mtim = vap->va_mtime; - sb->st_ctim = vap->va_ctime; - sb->st_birthtim = vap->va_birthtime; + sb->st_atim.tv_sec = vap->va_atime.tv_sec; + sb->st_atim.tv_nsec = vap->va_atime.tv_nsec; + sb->st_mtim.tv_sec = vap->va_mtime.tv_sec; + sb->st_mtim.tv_nsec = vap->va_mtime.tv_nsec; + sb->st_ctim.tv_sec = vap->va_ctime.tv_sec; + sb->st_ctim.tv_nsec = vap->va_ctime.tv_nsec; + sb->st_birthtim.tv_sec = vap->va_birthtime.tv_sec; + sb->st_birthtim.tv_nsec = vap->va_birthtime.tv_nsec; /* * According to www.opengroup.org, the meaning of st_blksize is
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