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authorDenys Vlasenko <vda.linux@googlemail.com>2019-04-29 17:59:08 +0200
committerDenys Vlasenko <vda.linux@googlemail.com>2019-04-29 17:59:08 +0200
commitf3a064f4956e113978e74486300dcd1e3e044efa (patch)
tree1a122c33fd15dce4563cd70e3c3e2c852578986b
parentfa8878bf1fe331df752395cce90da212e25e07b7 (diff)
downloadbusybox-f3a064f4956e113978e74486300dcd1e3e044efa.tar.gz
libbbb: find_mount_point() too eager to stat mounted devices
None of the below "devices" (first word on the line) are real. sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0 proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0 devtmpfs /dev devtmpfs rw,nosuid,size=7917900k,nr_inodes=1979475,mode=755 0 0 tmpfs /dev/shm tmpfs rw,nosuid,nodev 0 0 devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0 tmpfs /run tmpfs rw,nosuid,nodev,mode=755 0 0 pstore /sys/fs/pstore pstore rw,nosuid,nodev,noexec,relatime 0 0 configfs /sys/kernel/config configfs rw,relatime 0 0 tmpfs /tmp tmpfs rw,relatime 0 0 function old new delta find_mount_point 297 302 +5 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--libbb/find_mount_point.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/libbb/find_mount_point.c b/libbb/find_mount_point.c
index 94bbf1d4a..0e1be3820 100644
--- a/libbb/find_mount_point.c
+++ b/libbb/find_mount_point.c
@@ -56,11 +56,22 @@ struct mntent* FAST_FUNC find_mount_point(const char *name, int subdir_too)
continue;
/* Is device's dev_t == name's dev_t? */
- if (stat(mountEntry->mnt_fsname, &s) == 0 && s.st_rdev == devno_of_name)
+ if (mountEntry->mnt_fsname[0] == '/'
+ /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ * avoid stat'ing "sysfs", "proc", "none" and such,
+ * useless at best, can stat unrelated files at worst.
+ */
+ && stat(mountEntry->mnt_fsname, &s) == 0
+ && s.st_rdev == devno_of_name
+ ) {
break;
+ }
/* Match the directory's mount point. */
- if (stat(mountEntry->mnt_dir, &s) == 0 && s.st_dev == devno_of_name)
+ if (stat(mountEntry->mnt_dir, &s) == 0
+ && s.st_dev == devno_of_name
+ ) {
break;
+ }
}
endmntent(mtab_fp);