Date: Wed, 20 Jun 2012 02:21:53 +0000 (UTC) From: Kevin Lo <kevlo@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r237284 - head/bin/rm Message-ID: <201206200221.q5K2LrXM012793@svn.freebsd.org>
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Author: kevlo Date: Wed Jun 20 02:21:53 2012 New Revision: 237284 URL: http://svn.freebsd.org/changeset/base/237284 Log: Fix potential symlink race condition in "rm -P" by adding a check that the file we have opened is the one we expected. Also open in non-blocking mode to avoid a potential hang with FIFOs. Obtained from: NetBSD via OpenBSD Modified: head/bin/rm/rm.c Modified: head/bin/rm/rm.c ============================================================================== --- head/bin/rm/rm.c Wed Jun 20 00:41:31 2012 (r237283) +++ head/bin/rm/rm.c Wed Jun 20 02:21:53 2012 (r237284) @@ -408,7 +408,7 @@ rm_file(char **argv) int rm_overwrite(char *file, struct stat *sbp) { - struct stat sb; + struct stat sb, sb2; struct statfs fsb; off_t len; int bsize, fd, wlen; @@ -427,8 +427,15 @@ rm_overwrite(char *file, struct stat *sb file, sbp->st_ino); return (0); } - if ((fd = open(file, O_WRONLY, 0)) == -1) + if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1) goto err; + if (fstat(fd, &sb2)) + goto err; + if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino || + !S_ISREG(sb2.st_mode)) { + errno = EPERM; + goto err; + } if (fstatfs(fd, &fsb) == -1) goto err; bsize = MAX(fsb.f_iosize, 1024);
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