[git commit] mount: -T OTHERTAB support
Denys Vlasenko
vda.linux at googlemail.com
Wed Mar 11 15:07:24 UTC 2015
commit: http://git.busybox.net/busybox/commit/?id=7b434a67dcaa88047095cf0196941c5456bb1c87
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
function old new delta
mount_main 1221 1241 +20
packed_usage 30616 30610 -6
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
Signed-off-by: Isaac Dunham <ibid.ag at gmail.com>
---
util-linux/Config.src | 88 -------------------------------------
util-linux/mount.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 108 insertions(+), 94 deletions(-)
diff --git a/util-linux/Config.src b/util-linux/Config.src
index c1cd6da..854b368 100644
--- a/util-linux/Config.src
+++ b/util-linux/Config.src
@@ -434,94 +434,6 @@ config MORE
you will probably find this utility very helpful. If you don't have
any need to reading text files, you can leave this disabled.
-config MOUNT
- bool "mount"
- default y
- select PLATFORM_LINUX
- help
- All files and filesystems in Unix are arranged into one big directory
- tree. The 'mount' utility is used to graft a filesystem onto a
- particular part of the tree. A filesystem can either live on a block
- device, or it can be accessible over the network, as is the case with
- NFS filesystems. Most people using BusyBox will also want to enable
- the 'mount' utility.
-
-config FEATURE_MOUNT_FAKE
- bool "Support option -f"
- default y
- depends on MOUNT
- help
- Enable support for faking a file system mount.
-
-config FEATURE_MOUNT_VERBOSE
- bool "Support option -v"
- default y
- depends on MOUNT
- help
- Enable multi-level -v[vv...] verbose messages. Useful if you
- debug mount problems and want to see what is exactly passed
- to the kernel.
-
-config FEATURE_MOUNT_HELPERS
- bool "Support mount helpers"
- default n
- depends on MOUNT
- help
- Enable mounting of virtual file systems via external helpers.
- E.g. "mount obexfs#-b00.11.22.33.44.55 /mnt" will in effect call
- "obexfs -b00.11.22.33.44.55 /mnt"
- Also "mount -t sometype [-o opts] fs /mnt" will try
- "sometype [-o opts] fs /mnt" if simple mount syscall fails.
- The idea is to use such virtual filesystems in /etc/fstab.
-
-config FEATURE_MOUNT_LABEL
- bool "Support specifying devices by label or UUID"
- default y
- depends on MOUNT
- select VOLUMEID
- help
- This allows for specifying a device by label or uuid, rather than by
- name. This feature utilizes the same functionality as blkid/findfs.
- This also enables label or uuid support for swapon.
-
-config FEATURE_MOUNT_NFS
- bool "Support mounting NFS file systems on Linux < 2.6.23"
- default n
- depends on MOUNT
- select FEATURE_HAVE_RPC
- select FEATURE_SYSLOG
- help
- Enable mounting of NFS file systems on Linux kernels prior
- to version 2.6.23. Note that in this case mounting of NFS
- over IPv6 will not be possible.
-
- Note that this option links in RPC support from libc,
- which is rather large (~10 kbytes on uclibc).
-
-config FEATURE_MOUNT_CIFS
- bool "Support mounting CIFS/SMB file systems"
- default y
- depends on MOUNT
- help
- Enable support for samba mounts.
-
-config FEATURE_MOUNT_FLAGS
- depends on MOUNT
- bool "Support lots of -o flags in mount"
- default y
- help
- Without this, mount only supports ro/rw/remount. With this, it
- supports nosuid, suid, dev, nodev, exec, noexec, sync, async, atime,
- noatime, diratime, nodiratime, loud, bind, move, shared, slave,
- private, unbindable, rshared, rslave, rprivate, and runbindable.
-
-config FEATURE_MOUNT_FSTAB
- depends on MOUNT
- bool "Support /etc/fstab and -a"
- default y
- help
- Support mount all and looking for files in /etc/fstab.
-
config PIVOT_ROOT
bool "pivot_root"
default y
diff --git a/util-linux/mount.c b/util-linux/mount.c
index 62fd41f..fbc89c8 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -17,8 +17,103 @@
// mount_it_now() does the actual mount.
//
+//config:config MOUNT
+//config: bool "mount"
+//config: default y
+//config: select PLATFORM_LINUX
+//config: help
+//config: All files and filesystems in Unix are arranged into one big directory
+//config: tree. The 'mount' utility is used to graft a filesystem onto a
+//config: particular part of the tree. A filesystem can either live on a block
+//config: device, or it can be accessible over the network, as is the case with
+//config: NFS filesystems. Most people using BusyBox will also want to enable
+//config: the 'mount' utility.
+//config:
+//config:config FEATURE_MOUNT_FAKE
+//config: bool "Support option -f"
+//config: default y
+//config: depends on MOUNT
+//config: help
+//config: Enable support for faking a file system mount.
+//config:
+//config:config FEATURE_MOUNT_VERBOSE
+//config: bool "Support option -v"
+//config: default y
+//config: depends on MOUNT
+//config: help
+//config: Enable multi-level -v[vv...] verbose messages. Useful if you
+//config: debug mount problems and want to see what is exactly passed
+//config: to the kernel.
+//config:
+//config:config FEATURE_MOUNT_HELPERS
+//config: bool "Support mount helpers"
+//config: default n
+//config: depends on MOUNT
+//config: help
+//config: Enable mounting of virtual file systems via external helpers.
+//config: E.g. "mount obexfs#-b00.11.22.33.44.55 /mnt" will in effect call
+//config: "obexfs -b00.11.22.33.44.55 /mnt"
+//config: Also "mount -t sometype [-o opts] fs /mnt" will try
+//config: "sometype [-o opts] fs /mnt" if simple mount syscall fails.
+//config: The idea is to use such virtual filesystems in /etc/fstab.
+//config:
+//config:config FEATURE_MOUNT_LABEL
+//config: bool "Support specifying devices by label or UUID"
+//config: default y
+//config: depends on MOUNT
+//config: select VOLUMEID
+//config: help
+//config: This allows for specifying a device by label or uuid, rather than by
+//config: name. This feature utilizes the same functionality as blkid/findfs.
+//config: This also enables label or uuid support for swapon.
+//config:
+//config:config FEATURE_MOUNT_NFS
+//config: bool "Support mounting NFS file systems on Linux < 2.6.23"
+//config: default n
+//config: depends on MOUNT
+//config: select FEATURE_HAVE_RPC
+//config: select FEATURE_SYSLOG
+//config: help
+//config: Enable mounting of NFS file systems on Linux kernels prior
+//config: to version 2.6.23. Note that in this case mounting of NFS
+//config: over IPv6 will not be possible.
+//config:
+//config: Note that this option links in RPC support from libc,
+//config: which is rather large (~10 kbytes on uclibc).
+//config:
+//config:config FEATURE_MOUNT_CIFS
+//config: bool "Support mounting CIFS/SMB file systems"
+//config: default y
+//config: depends on MOUNT
+//config: help
+//config: Enable support for samba mounts.
+//config:
+//config:config FEATURE_MOUNT_FLAGS
+//config: depends on MOUNT
+//config: bool "Support lots of -o flags in mount"
+//config: default y
+//config: help
+//config: Without this, mount only supports ro/rw/remount. With this, it
+//config: supports nosuid, suid, dev, nodev, exec, noexec, sync, async, atime,
+//config: noatime, diratime, nodiratime, loud, bind, move, shared, slave,
+//config: private, unbindable, rshared, rslave, rprivate, and runbindable.
+//config:
+//config:config FEATURE_MOUNT_FSTAB
+//config: depends on MOUNT
+//config: bool "Support /etc/fstab and -a"
+//config: default y
+//config: help
+//config: Support mount all and looking for files in /etc/fstab.
+//config:
+//config:config FEATURE_MOUNT_OTHERTAB
+//config: depends on FEATURE_MOUNT_FSTAB
+//config: bool "Support -T <alt_fstab>"
+//config: default y
+//config: help
+//config: Support mount -T (specifying an alternate fstab)
+
//usage:#define mount_trivial_usage
-//usage: "[OPTIONS] [-o OPTS] DEVICE NODE"
+//usage: "[OPTIONS] [-o OPT] DEVICE NODE"
//usage:#define mount_full_usage "\n\n"
//usage: "Mount a filesystem. Filesystem autodetection requires /proc.\n"
//usage: "\n -a Mount all filesystems in fstab"
@@ -41,8 +136,11 @@
//usage: )
////usage: "\n -s Sloppy (ignored)"
//usage: "\n -r Read-only mount"
-//usage: "\n -w Read-write mount (default)"
+////usage: "\n -w Read-write mount (default)"
//usage: "\n -t FSTYPE[,...] Filesystem type(s)"
+//usage: IF_FEATURE_MOUNT_OTHERTAB(
+//usage: "\n -T FILE Read FILE instead of /etc/fstab"
+//usage: )
//usage: "\n -O OPT Mount only filesystems with option OPT (-a only)"
//usage: "\n-o OPT:"
//usage: IF_FEATURE_MOUNT_LOOP(
@@ -64,7 +162,7 @@
//usage: "\n move Relocate an existing mount point"
//usage: )
//usage: "\n remount Remount a mounted filesystem, changing flags"
-//usage: "\n ro/rw Same as -r/-w"
+//usage: "\n ro Same as -r"
//usage: "\n"
//usage: "\nThere are filesystem-specific -o flags."
//usage:
@@ -167,7 +265,7 @@ enum {
};
-#define OPTION_STR "o:t:rwanfvsiO:"
+#define OPTION_STR "o:t:rwanfvsiO:" IF_FEATURE_MOUNT_OTHERTAB("T:")
enum {
OPT_o = (1 << 0),
OPT_t = (1 << 1),
@@ -180,6 +278,7 @@ enum {
OPT_s = (1 << 8),
OPT_i = (1 << 9),
OPT_O = (1 << 10),
+ OPT_T = (1 << 11),
};
#if ENABLE_FEATURE_MTAB_SUPPORT
@@ -2034,7 +2133,7 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
char *O_optmatch = NULL;
char *storage_path;
llist_t *lst_o = NULL;
- const char *fstabname;
+ const char *fstabname = "/etc/fstab";
FILE *fstab;
int i, j;
int rc = EXIT_SUCCESS;
@@ -2061,6 +2160,7 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
// Max 2 params; -o is a list, -v is a counter
opt_complementary = "?2o::" IF_FEATURE_MOUNT_VERBOSE("vv");
opt = getopt32(argv, OPTION_STR, &lst_o, &fstype, &O_optmatch
+ IF_FEATURE_MOUNT_OTHERTAB(, &fstabname)
IF_FEATURE_MOUNT_VERBOSE(, &verbose));
while (lst_o) append_mount_options(&cmdopts, llist_pop(&lst_o)); // -o
if (opt & OPT_r) append_mount_options(&cmdopts, "ro"); // -r
@@ -2128,8 +2228,10 @@ int mount_main(int argc UNUSED_PARAM, char **argv)
return rc;
}
+ // A malicious user could overmount /usr without this.
+ if (ENABLE_FEATURE_MOUNT_OTHERTAB && nonroot)
+ fstabname = "/etc/fstab";
// Open either fstab or mtab
- fstabname = "/etc/fstab";
if (cmdopt_flags & MS_REMOUNT) {
// WARNING. I am not sure this matches util-linux's
// behavior. It's possible util-linux does not
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