From 71bf78844425d228de76db36c2f97e542c4c54fe Mon Sep 17 00:00:00 2001 From: KaiGai Kohei Date: Mon, 22 Oct 2007 10:30:19 +0200 Subject: [PATCH] mkswap: possible to crash with SELinux relabeling support When fgetfilecon() is failed with -ENODATA, this process does not exit. However, "oldcontext" is not initialized in this case, so context_new() will be called with uninitialized "oldcontext" at the next. Finally, it makes a segmentation fault, because context_new() have to refer an incorrect memory region. The attached patch fixes this matter using matchpathcon(). If we cannot obtain actual file context due to -ENODATA, a context which is returned by matchpathcon() is applied as oldcontext. Then, the type of the context is relabeled to "swapfile_t" explicitly. Signed-off-by: KaiGai Kohei Signed-off-by: Karel Zak --- disk-utils/mkswap.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/disk-utils/mkswap.c b/disk-utils/mkswap.c index 6af1ff7b..2394368b 100644 --- a/disk-utils/mkswap.c +++ b/disk-utils/mkswap.c @@ -738,12 +738,15 @@ the -f option to force it.\n"), security_context_t oldcontext; context_t newcontext; - if ((fgetfilecon(DEV, &oldcontext) < 0) && - (errno != ENODATA)) { - fprintf(stderr, _("%s: %s: unable to obtain selinux file label: %s\n"), - program_name, device_name, - strerror(errno)); - exit(1); + if (fgetfilecon(DEV, &oldcontext) < 0) { + if (errno != ENODATA) { + fprintf(stderr, _("%s: %s: unable to obtain selinux file label: %s\n"), + program_name, device_name, + strerror(errno)); + exit(1); + } + if (matchpathcon(device_name, statbuf.st_mode, &oldcontext)) + die(_("unable to matchpathcon()")); } if (!(newcontext = context_new(oldcontext))) die(_("unable to create new selinux context")); -- 2.39.5