From 4ec1405b3943fed9dff52930055b037cc7a40069 Mon Sep 17 00:00:00 2001 From: Kevin Lo Date: Wed, 20 Jun 2012 02:21:53 +0000 Subject: [PATCH] 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 --- bin/rm/rm.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/bin/rm/rm.c b/bin/rm/rm.c index 3c2ba61b3c54..1f81885d52cc 100644 --- a/bin/rm/rm.c +++ b/bin/rm/rm.c @@ -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 *sbp) 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);